HPLC - High Performance Liquid Chromatography What Is HPLC (High Performance Liquid Chromatography)? Brief History and Definition Liquid chromatography was defined in the early 1900s by the work of the Russian botanist, Mikhail S. Tswett. His pioneering studies focused on separating compounds [leaf pigments], extracted from plants using a solvent, in a column packed with particles. Tswett filled an open glass column with particles. Two specific materials that he found useful were powdered chalk [calcium carbonate] and alumina. He poured his sample [solvent extract of homogenized plant leaves] into the column and allowed it to pass into the particle bed. This was followed by pure solvent. As the sample passed down through the column by gravity, different colored bands could be seen separating because some components were moving faster than others. He related these separated, different-colored bands to the different compounds that were originally contained in the sample. He had created an analytical separation of these compounds based on the differing strength of each compound’s chemical attraction to the particles. The compounds that were more strongly attracted to the particles slowed down, while other compounds more strongly attracted to the solvent moved faster. This process can be described as follows: the compounds contained in the sample distribute, or partition differently between the moving solvent, called the mobile phase, and the particles, called the stationary phase. This causes each compound to move at a different speed, thus creating a separation of the compounds. Tswett coined the name chromatography [from the Greek words chroma, meaning color, and graph, meaning writing—literally, color writing] to describe his colorful experiment. [Curiously, the Russian name Tswett means color.] Today, liquid chromatography, in its various forms, has become one of the most powerful tools in analytical chemistry.
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HPLC - High Performance Liquid ChromatographyWhat Is HPLC (High Performance Liquid Chromatography)?
Brief History and Definition
Liquid chromatography was defined in the early 1900s by the work of the Russian botanist, Mikhail S.
Tswett. His pioneering studies focused on separating compounds [leaf pigments], extracted from
plants using a solvent, in a column packed with particles.
Tswett filled an open glass column with particles. Two specific materials that he found useful were
powdered chalk [calcium carbonate] and alumina. He poured his sample [solvent extract of
homogenized plant leaves] into the column and allowed it to pass into the particle bed. This was
followed by pure solvent. As the sample passed down through the column by gravity, different colored
bands could be seen separating because some components were moving faster than others. He
related these separated, different-colored bands to the different compounds that were originally
contained in the sample. He had created an analytical separation of these compounds based on the
differing strength of each compound’s chemical attraction to the particles. The compounds that were
more strongly attracted to the particles slowed down, while other compounds more strongly attracted
to the solvent moved faster. This process can be described as follows: the compounds contained in the
sample distribute, or partition differently between the moving solvent, called the mobile phase, and
the particles, called the stationary phase. This causes each compound to move at a different speed,
thus creating a separation of the compounds.
Tswett coined the name chromatography [from the Greek words chroma, meaning color, and graph,
meaning writing—literally, color writing] to describe his colorful experiment. [Curiously, the Russian
name Tswett means color.] Today, liquid chromatography, in its various forms, has become one of the
most powerful tools in analytical chemistry.
Figure A: Tswett's Experiment
Liquid Chromatography (LC) Techniques
Liquid chromatography can be performed using planar [Techniques 1 and 2] or column techniques
[Technique 3]. Column liquid chromatography is the most powerful and has the highest capacity for
sample. In all cases, the sample first must be dissolved in a liquid that is then transported either onto,
or into, the chromatographic device.
Technique 1. The sample is spotted onto, and then flows through, a thin layer of chromatographic
particles [stationary phase] fixed onto the surface of a glass plate [Figure B]. The bottom edge of the
plate is placed in a solvent. Flow is created by capillary action as the solvent [mobile phase] diffuses
into the dry particle layer and moves up the glass plate. This technique is called thin-layer
chromatography or TLC.
Figure B: Thin-layer Chromatography
Note that the black sample is a mixture of FD&C yellow, red and blue food dyes that has been
chromatographically separated.
Technique 2. In Figure C, samples are spotted onto paper [stationary phase]. Solvent [mobile phase]
is then added to the center of the spot to create an outward radial flow. This is a form of paper
chromatography. [Classic paper chromatography is performed in a manner similar to that of TLC with
linear flow.] In the upper image, the same black FD&C dye sample is applied to the paper.
Figure C: Paper Chromatography
Notice the difference in separation power for this particular paper when compared to the TLC plate.
The green ring indicates that the paper cannot separate the yellow and blue dyes from each other, but
it could separate those dyes from the red dyes. In the bottom image, a green sample, made up of the
same yellow and blue dyes, is applied to the paper. As you would predict, the paper cannot separate
the two dyes. In the middle, a purple sample, made up of red and blue dyes, was applied to the paper.
They are well separated.
Technique 3. In this, the most powerful approach, the sample passes through a column or a cartridge
device containing appropriate particles [stationary phase]. These particles are called the
chromatographic packing material. Solvent [mobile phase] flows through the device. In solid-phase
extraction [SPE], the sample is loaded onto the cartridge and the solvent stream carries the sample
through the device. As in Tswett’s experiment, the compounds in the sample are then separated by
traveling at different individual speeds through the device. Here the black sample is loaded onto a
cartridge. Different solvents are used in each step to create the separation.
acetone [a ketone], and, finally, methanol [an alcohol] at the strong end [see Figure R-1].
†W. Trappe, Biochem. Z. 305: 150 [1940]
††L. R. Snyder, Principles of Adsorption Chromatography, Marcel Dekker [1968], pp. 192-197
†††R. Neher in G.B. Marini-Bettòlo, ed., Thin-Layer Chromatography, Elsevier [1964] pp. 75-86.
Elute* [verb]
To chromatograph by elution chromatography. The process of elution may be stopped while all the
sample components are still on the chromatographic bed [planar thin-layer or paper chromatography]
or continued until the components have left the chromatographic bed [column chromatography].
Note: The term elute is preferred to develop [a term used in planar chromatography], to avoid
confusion with the practice of method development, whereby a separation system [the combination of
mobile and stationary phases] is optimized for a particular separation.
Elution Chromatography*
A procedure for chromatographic separation in which the mobile phase is continuously passed through
the chromatographic bed. In HPLC, once the detector baseline has stabilized and the separation
system has reached equilibrium, a finite slug of sample is introduced into the flowing mobile phase
stream. Elution continues until all analytes of interest have passed through the detector.
Elution Strength
A measure of the affinity of a solvent relative to that of the analyte for the stationary phase. A weak
solvent cannot displace the analyte, causing it to be strongly retained on the stationary phase. A
strong solvent may totally displace all the analyte molecules and carry them through the column
unretained. To achieve a proper balance of effective separation and reasonable elution volume,
solvents are often blended to set up an appropriate competition between the phases, thereby
optimizing both selectivity and
separation time for a given set of analytes [see Selectivity].
Dipole moment, dielectric constant, hydrogen bonding, molecular size and shape, and surface tension
may give some indication of elution strength. Elution strength is also determined by the separation
mode. An eluotropic series of solvents may be ordered by increasing strength in one direction under
adsorption or normal-phase conditions; that order may be nearly opposite under reversed-phase
partition conditions [see Figure R-1].
Fluorescence Detector
Fluorescence detectors excite a sample with a specified wavelength of light. This causes certain
compounds to fluoresce and emit light at a higher wavelength. A sensor, set to a specific emission
wavelength and masked so as not to be blinded by the excitation source, collects only the emitted
light. Often analytes that do not natively fluoresce may be derivatized to take advantage of the high
sensitivity and selectivity of this form of detection, e.g., AccQ•Tag™ derivatization of amino acids.
Flow Rate*
The volume of mobile phase passing through the column in unit time. In HPLC systems, the flow rate is
set by the controller for the solvent delivery system [pump]. Flow rate accuracy can be checked by
timed collection and measurement of the effluent at the column outlet. Since a solvent’s density varies
with temperature, any calibration or flow rate measurement must take this variable into account. Most
accurate determinations are made, when possible, by weight, not volume.
Uniformity [precision] and reproducibility of flow rate is important to many LC techniques, especially in
separations where retention times are key to analyte identification, or in gel-permeation
chromatography where calibration and correlation of retention times are critical to accurate molecular-
weight-distribution measurements of polymers.
Often, separation conditions are compared by means of linear velocity, not flow rate. The linear
velocity is calculated by dividing the flow rate by the cross-sectional area of the column. While flow
rate is expressed in volume/time [e.g., mL/min], linear velocity is measured in length/time [e.g.,
mm/sec].
Gel-Permeation Chromatography*
Separation based mainly upon exclusion effects due to differences in molecular size and/or shape.
Gelpermeation chromatography and gel filtration chromatography describe the process when the
stationary phase is a swollen gel. Both are forms of size-exclusion chromatography. Porath and Flodin
first described gel-filtration using dextran gels and aqueous mobile phases for the size-based
separation of biomolecules.† Moore applied similar principles to the separation of organic polymers by
size in solution using
organic-solvent mobile phases on porous polystyrene-divinylbenzene polymer gels.††
†J. Porath, P. Flodin, Nature 183: 1657-1659 [1959]
††J.C. Moore, U.S. Patent 3,326,875 [filed Jan. 1963; issued June 1967]
Gradient
The change over time in the relative concentrations of two [or more] miscible solvent components that
form a mobile phase of increasing elution strength. A step gradient is typically used in solid-phase
extraction; in each step, the eluent composition is changed abruptly from a weaker mobile phase to a
stronger mobile phase. It is even possible, by drying the SPE sorbent bed in between steps, to change
from one solvent to another immiscible solvent.
A continuous gradient is typically generated by a low- or high-pressure mixing system [see Figures J-2
and J-3] according to a pre-determined curve [linear or non-linear] representing the concentration of
the stronger solvent B in the initial solvent A over a fixed time period. A hold at a fixed isocratic
solvent composition can be programmed at any time point within a continuous gradient. At the end of
a separation, the gradient program can also be set to return to the initial mobile phase composition to
re-equilibrate the column in preparation for the injection of the next sample. Sophisticated HPLC
systems can blend as many as four or more solvents [or solvent mixtures] into a continuous gradient.
Injector [Autosampler, Sample Manager]
A mechanism for accurately and precisely introducing [injecting] a discrete, predetermined volume of
a sample solution into the flowing mobile phase stream. The injector can be a simple manual device, or
a sophisticated autosampler that can be programmed for unattended injections of many samples from
an array of individual vials or wells in a predetermined sequence. Sample compartments in these
systems may even be temperature controlled to maintain sample integrity over many hours of
operation.
Most modern injectors incorporate some form of syringe-filled sample loop that can be switched on- or
offline by means of a multi-port valve. A well-designed, minimal-internal-volume injection system is
situated as close to the column inlet as possible and minimizes the spreading of the sample band.
Between sample injections, it is also capable of being flushed to waste by mobile phase, or a wash
solvent, to prevent carryover [contamination of the present sample by a previous one].
Samples are best prepared for injection, if possible, by dissolving them in the mobile phase into which
they will be injected; this may prevent issues with separation and/or detection. If another solvent must
be used, it is desirable that its elution strength be equal to or less than that of the mobile phase. It is
often wise to mix a bit of a sample solution with the mobile phase offline to test for precipitation or
miscibility issues that might compromise a successful separation.
Inlet
The end of the column bed where the mobile phase stream and sample enter. A porous, inert frit
retains the packing material and protects the sorbent bed inlet from particulate contamination. Good
HPLC practice dictates that samples and mobile phases should be particulate-free; this becomes
imperative for small-particle columns whose inlets are much more easily plugged. If the column bed
inlet becomes clogged and exhibits higher-than-normal backpressure, sometimes, reversing the flow
direction while directing the effluent to waste may dislodge and flush out sample debris that sits atop
the frit. If the
debris has penetrated the frit and is lodged in the inlet end of the bed itself, then the column has most
likely reached the end of its useful life.
Ion-Exchange Chromatography* [see section: Separations Based on Charge]
This separation mode is based mainly on differences in the ion-exchange affinities of the sample
components. Separation of primarily inorganic ionic species in water or buffered aqueous mobile
phases on small particle, superficially porous, high-efficiency, ion-exchange columns followed by
conductometric or electrochemical detection is referred to as ion chromatography [IC].
Isocratic Elution*
A procedure in which the composition of the mobile phase remains constant during the elution
process.
Liquid Chromatography* [LC]
A separation technique in which the mobile phase is a liquid. Liquid chromatography can be carried out
either in a column or on a plane [TLC or paper chromatography]. Modern liquid chromatography
utilizing smaller particles and higher inlet pressure was termed high-performance (or high-pressure)
liquid chromatography [HPLC] in 1970. In 2004, ultra-performance liquid chromatography dramatically
raised the performance of LC to a new plateau [see UPLC Technology].
Mobile Phase* [see Eluate, Eluent]
A fluid that percolates, in a definite direction, through the length of the stationary-phase sorbent bed.
The mobile phase may be a liquid [liquid chromatography] or a gas [gas chromatography] or a
supercritical fluid [supercritical-fluid chromatography]. In gas chromatography the expression carrier
gas may be used for the mobile phase. In elution chromatography, the mobile phase may also be
called the eluent, while the word eluate is defined as the portion of the mobile phase that has passed
through the sorbent bed and contains the compounds of interest in solution.
Normal-Phase Chromatography*
An elution procedure in which the stationary phase is more polar than the mobile phase. This term is
used in liquid chromatography to emphasize the contrast to reversed-phase chromatography.
Peak* [see Plate Number]
The portion of a differential chromatogram recording the detector response while a single component
is eluted from the column. If separation is incomplete, two or more components may be eluted as one
unresolved peak. Peaks eluted under optimal conditions from a well-packed, efficient column, operated
in a system that minimizes bandspreading, approach the shape of a Gaussian distribution. Quantitation
is usually done by measuring the peak area [enclosed by the baseline and the peak curve]. Less often,
peak height [the distance measured from the peak apex to the baseline] may be used for quantitation.
This procedure requires that both the peak width and the peak shape remain constant.
Plate Number* [N, see Efficiency]
A number indicative of column performance [mechanical separation power or efficiency, also called
plate count, number of theoretical plates, or theoretical plate number]. It relates the magnitude of a
peak’s retention to its width [variance or bandspread]. In order to calculate a plate count, it is assumed
that a peak can be represented by a Gaussian distribution [a statistical bell curve]. At the inflection
points [60.7% of peak height], the width of a Gaussian curve is twice the standard deviation [σ] about
its mean [located at the peak apex]. As shown in Figure U, a Gaussian curve’s peak width measured at
other fractions of peak height can be expressed in precisely defined multiples of σ. Peak retention
[retention volume, VR, or retention time, tR] and peak width must be expressed in the same units,
because method of calculating N is aN is a dimensionless number. Note that the 5 sigma more
stringent measure of column homogeneity and performance, as it is more severely affected by peak
asymmetry. Computer data stations can automatically delineate each resolved peak and calculate its
corresponding plate number.
Preparative Chromatography
The process of using liquid chromatography to isolate a compound in a quantity and at a purity level
sufficient for further experiments or uses. For pharmaceutical or biotechnological purification
processes, columns several feet in diameter can be used for multiple kilograms of material. For
isolating just a few micrograms of a valuable natural product, an analytical HPLC column is sufficient.
Both are preparative chromatographic approaches, differing only in scale [see section on HPLC Scale
and Table A].
Resolution* [Rs, see Selectivity]
The separation of two peaks, expressed as the difference in their corresponding retention times,
divided by their average peak width at the baseline. Rs = 1.25 indicates that two peaks of equal width
are just separated at the baseline. When Rs = 0.6, the only visual indication of the presence of two
peaks on a chromatogram is a small notch near the peak apex. Higher efficiency columns produce
narrower peaks and improve resolution for difficult separations; however, resolution increases by only
the square root of N. The most powerful method of increasing resolution is to increase selectivity by
altering the mobile/stationary phase combination used for the chromatographic separation [see
section on Chemical Separation Power].
Retention Factor* [k]
A measure of the time the sample component resides in the stationary phase relative to the time it
resides in the mobile phase; it expresses how much longer a sample component is retarded by the
stationary phase than it would take to travel through the column with the velocity of the mobile phase.
Mathematically, it is the ratio of the adjusted retention time [volume] and the hold-up time [volume]: k
= tR'/tM [see Retention Time and Selectivity].
Note: In the past, this term has also been expressed as partition ratio, capacity ratio, capacity factor,
or mass distribution ratio and symbolized by k'.
Retention Time* [tR]
The time between the start of elution [typically, in HPLC, the moment of injection or sample
introduction] and the emergence of the peak maximum. The adjusted retention time, tR', is calculated
by subtracting from tR the hold-up time [tM, the time from injection to the elution of the peak
maximum of a totally unretained analyte].
Reversed-Phase Chromatography*
An elution procedure used in liquid chromatography in which the mobile phase is significantly more
polar than the stationary phase, e.g. a microporous silica-based material with alkyl chains chemically
bonded to its accessible surface. Note: Avoid the incorrect term reverse phase. [See Reference 4 for
some novel ideas on the mechanism of reversed-phase separations.]
Selectivity [Separation Factor, σ]
A term used to describe the magnitude of the difference between the relative thermodynamic affinities
of a pair of analytes for the specified mobile and stationary phases that comprise the separation
system. The proper term is separation factor [σ]. It equals the ratio of retention factors, k2/k1 = 1,
then bothis always ≥ 1. If σ [see Retention Factor]; by definition, σ peaks co-elute, and no
separation is obtained. It is important in preparative chromatography to maximize α for highest sample
loadability and throughput. [see section on Chemical Separation Power]
Sensitivity* [S]
The signal output per unit concentration or unit mass of a substance in the mobile phase entering the
detector, e.g., the slope of a linear calibration curve [see Detector]. For concentration-sensitive
detectors [e.g., UV/VIS absorbance], sensitivity is the ratio of peak height to analyte concentration in
the peak. For mass-flow-sensitive detectors, it is the ratio of peak height to unit mass. If sensitivity is
to be a unique performance characteristic, it must depend only on the chemical measurement process,
not upon scale factors.
The ability to detect [qualify] or measure [quantify] an analyte is governed by many instrumental and
chemical factors. Well-resolved peaks [maximum selectivity] eluting from high efficiency columns
[narrow peak width with good symmetry for maximum peak height] as well as good detector
sensitivity and specificity are ideal. Both the separation system interference and electronic component
noise should also be minimized to achieve maximum sensitivity.
Solid-Phase Extraction [SPE]
A sample preparation technique that uses LC principles to isolate, enrich, and/or purify analytes from a
complex matrix applied to a miniature chromatographic bed. Offline SPE is done [manually or via
automation] with larger particles in individual plastic cartridges or in micro-elution plate wells, using
low positive pressure or vacuum to assist flow. Online SPE is done with smaller particles in miniature
HPLC columns using higher pressures and a valve to switch the SPE column online with the primary
HPLC column, or offline to waste, as appropriate.
SPE methods use step gradients [see Gradient] to accomplish bed conditioning, sample loading,
washing, and elution steps. Samples are loaded typically under conditions where the k of important
analytes is as high as possible, so that they are fully retained during loading and washing steps.
Elution is then done by switching to a much stronger solvent mixture [see Elution Strength]. The goal
is to remove matrix interferences and to isolate the analyte in a solution, and at a concentration,
suitable for subsequent analysis.
Speed [see Efficiency, Flow Rate, Resolution]
A benefit of operating LC separations at higher linear velocities using smaller-volume, smaller-particle
analytical columns, or larger-volume, larger-particle preparative columns. Order-of-magnitude
advances in LC speed came in 1972 [with the use of 10 μm particles and pumps capable of delivering
accurate mobile-phase flow at 6000 psi], in 1976 [with 75-μm preparative columns operated at a flow
rate of 500 mL/min], and in 2004 [with the introduction of UPLC technology—1.7 μm-particle columns
operated at 15,000 psi].†
High-speed analytical LC systems must not only accommodate higher pressures throughout the
fluidics; injector cycle time must be short; gradient mixers must be capable of rapid turnaround
between samples; detector sensors must rapidly respond to tiny changes in eluate composition; and
data systems must collect the dozens of points each second required to plot and to quantitate narrow
peaks accurately.
Together, higher resolution, higher speed, and higher efficiency typically deliver higher throughput.
More samples can be analyzed in a workday. Larger quantities of compound can be purified per run or
per process period.
†See #3 on list of References for Further Reading above.
Stationary Phase*
One of the two phases forming a chromatographic system. It may be a solid, a gel, or a liquid. If a
liquid, it may be distributed on a solid. This solid may or may not contribute to the separation process.
The liquid may also be chemically bonded to the solid [bonded phase] or immobilized onto it
[immobilized phase].
The expression chromatographic bed or sorbent may be used as a general term to denote any of the
different forms in which the stationary phase is used.
The use of the term liquid phase to denote the mobile phase in LC is discouraged. This avoids
confusion with gas chromatography where the stationary phase is called a liquid phase [most often a
liquid coated on a solid support].
Open-column liquid-liquid partition chromatography [LLC] did not translate well to HPLC. It was
supplanted by the use of bonded-phase packings. LLC proved incompatible with modern detectors
because of problems with bleed of the stationary-phase-liquid coating off its solid support, thereby
contaminating the immiscible liquid mobile phase.
UPLC® Technology
The use of a high-efficiency LC system holistically designed to accommodate sub-2 μm particles and
very high operating pressure is termed ultra-performance liquid chromatography [UPLC technology].†
The major benefits of this technology are significant improvements in resolution over HPLC, and/or
faster run times while maintaining the resolution seen in an existing HPLC separation.
The growth of pharmaceutical industry is based on continuing success in producing new products whether they are used as therapeutic or prophylactic agents. The role of R&D is pivotal in this endeavor.
Pharmaceutical research is aimed at meeting the medical needs of the population for whom appropriate therapeutic remedies are not available or at those that are available are unsafe for prophylactic use for various disorders. While meeting medical needs, research also has to ensure that market needs for such exist and that the product will command sales and profits proportionate to investments. In cases where there are mismatches between these two, the products suffer the status of orphan drugs. The selection of an appropriate R&D portfolio is a strategic management exercise for a company, which should take into account apart from medical needs, innovative potential for success and available resources.
WHO Guidelines for Quality Standardized Herbal Formulations
a.Quality control of crude drugs material, plant preparations and finished products.
b.Stability assessment and shelf life.
c.Safety assessment; documentation of safety based on experience or toxicological studies.
d. Assessment of efficacy by ethnomedical informations and biological activity evaluations.
The bioactive extract should be standardized on the basis of active principles or major compounds along with the chromatographic fingerprints (TLC, HPTLC, HPLC and GC). The standardization of crude drug materials include the following steps:
1.Authentication (Stage of collection, parts of the plant collected, regional status, botanical identity like phytomorphology, microscopical and histological analysis, taxonomical identity, etc.)
2.Foreign matter (herbs collected should be free from soil, insect parts or animal excreta, etc.)
3.Organoleptic evaluation (sensory characters – taste, appearance, odor, feel of the drug, etc.)
4.Tissues of diagnostic importance present in the drug powder.
5. Ash values and extractive values.
6.Volatile matter
7.Moisture content determination
8.Chromatographic and spectroscopic evaluation. TLC, HPTLC, HPLC methods will provide qualitative and semi quantitative information about the main active constituents present in the crude drug as chemical markers in the TLC fingerprint evaluation of herbals (FEH). The quality of the drug can also be assessed on the basis of the chromatographic fingerprint.
9.Determination of heavy metals – e.g. cadmium, lead, arsenic, etc.
10.Pesticide residue – WHO and FAO (Food and Agricultural Organization) set limits of pesticides, which are usually present in the herbs. These pesticides are mixed with the herbs during the time of cultivation. Mainly pesticides like DDT, BHC, toxaphene, aldrin cause serious side-effects in human beings if the crude drugs are mixed with these agents.
11.Microbial contamination – usually medicinal plants containing bacteria and molds are coming from soil and atmosphere. Analysis of the limits of E. coli and molds clearly throws light towards the harvesting and production practices. The substance known as afflatoxins will produce serious side-effects if consumed along with the crude drugs.
Limits for Microbial Contamination
Microorganism Finished product Raw materials
E. coli 101 104
Salmonella - -
Total aerobic bacteria 105 -
Enterobacteria 103 -
Afflatoxins should be completely removed or should not be present.
12.Radioactive contamination – Microbial growth in herbals are usually avoided by irradiation. This process may sterilize the plant material but the radioactivity hazard should be taken into account. The radioactivity of the plant samples should be checked accordingly to the guidelines of International Atomic Energy (IAE) in Vienna and that of WHO.
In order to obtain quality oriented herbal products care should be taken right from the proper identification of plants; season and area of collection, extraction, isolation and verification process.
Chemical and instrumental analyses are routinely used for analyzing synthetic drugs to confirm its authenticity. In the case of herbal drugs, however the scene is different especially for polyherbal formulation, as there is no chemical or analytical methods available. Therefore biological-screening methods can be adopted for routine checkup of herbal drugs and formulations. In the case of herbal drugs, the quality of raw materials and products can be furnished by regular pharmacognostic identifications and phytochemical analysis. The herbal formulations in general can be standardized schematically as to formulate the medicament using raw materials collected from different localities and a comparative chemical efficacy of different batches of formulation are to be observed. The preparation with better clinical efficacy are to be selected. After all the routine physical, chemical and pharmacological parameters are to be checked for all the batches to select the final finished product and to validate the whole manufacturing process.
The stability parameters for the herbal formulations which includes physical parameters, chemical parameters, and microbiological parameters.
Physical parameters include color, appearance, odor, clarity, viscosity, moisture content, pH, disintegration time, friability, hardness, flowability, flocculation, sedimentation, settling rate and ash values.
Chemical parameters includes limit tests, extractive values, chemical assays, etc.
Chromatographic analysis of herbals can be done using TLC, HPLC, HPTLC and GC, UV, Fluorimetry, GC-MS, etc.
Microbiological parameters include total viable content, total mold count, total enterobacterial and their count. Limiters can be utilized as a quantitative or semiquantitative tool to ascertain and control the amount of impurities like the reagents used during abstraction of various herbs, impurities coming directly from the manufacturing vessels, impurities from the solvents, etc.
Chemical decomposition of substances present in the formulation also produces several toxic or impure compounds during storage in undesirable conditions. Contaminants may come directly from the atmosphere also. This include mainly dust, sulfur dioxide, H2S, CO2, Arsenic, moisture, etc.
The guidelines set by WHO can be summarized as follows:
a.Reference to the identity of the drug. Botanical evaluation – sensory characters, foreign organic matter, microscopical, histological, histochemical evaluation, quantitative measurements, etc.
b.Reference to the physiochemical character of the drug. Chromatographic profiles, ash values, extractive values, refractive index, polarimetric readings, moisture content, volatile oil content, etc.
c.Reference to the pharmacological parameters. Biological activity profiles, bitterness values, haemolytic index, astringency, swelling factor, foaming index, etc.
d.Toxicity details – heavy metals like cadmium, lead, arsenic, mercury, etc. Pesticide residues.
Maximum residue limits =
Acceptable daily index x body weight x extraction factor
--------------------------------------------------------------- x Therapeutic doses
Mean daily intake of drug x safety factor x 100
e.Microbial contamination – Total viable aerobic count, pathogenic bacteria like enterobacteria, E. coli, salmonella, Pseudomonous aeruginosa, Staphylococcus aureus, etc. and presence of afflatoxins etc.
f. Radioactive contamination.
Modern herbal ayurvedic monographs
In the modern herbal ayurvedic monographs the standardization parameters are discussed in a comprehensive way. According to the modern ayurvedic monograph the quality control protocols include the following:
Title, synonyms, publications related to that plant, constituents present, analytical methods.
Descriptive evaluation: Description of the drug, phytomorphological, microscopical, organoleptic evaluations, foreign matter, foreign minerals, etc.
Physicochemical parameters
Identity: Physical and chemical identity, chromatographic finger prints, ash values, extractive values, moisture content.
Strength: Ethanol and water extractive values, volatile oil and alkaloidal assays, quantitative estimation protocols, etc.
Biological Activity Evaluation
Bitterness values, astringency, swelling factor, form index, hemolytic index, etc.
Toxicological evaluation
Pesticide residues, heavy metals, microbial contamination like total viable aerobic count, pathogens like E. coli, Salmonella, P. aeruginosa, S. aureus, Enterobacteria, etc.
Aflatoxins
The presence of aflatoxins can be determined by chromatographic methods using standard aflatoxins B1, B2, G1, G2 mixtures. Aflatoxin is a product of the microbial strain Aspergillus flavus.
Radioactive Contaminants
Therapeutic Evaluation
Classical Evaluation as per Ayurvedic Literatures
Classical therapeutical attributes like Rasna, Guna, Virya, Vipaka and Karma classical formulations, doses, storage conditions.
The quality of the raw materials can be tested according to the following format:
Name of the drug (English, Regional names, Exact botanical nomenclature)
Part of the plant used
Area of collection
Distribution details
Season of Crop
Time and year of collection
Pesticide and insecticides
Condition of the drug (fresh or dry)
Form of the drug (powdered or intact or cuttings like etc.)
CONCLUSION
The subject of herbal drug standardization is massively wide and deep. There is so much to know and so much seemingly contradictory theories on the subject of herbal medicines and its relationship with human physiology and mental function.
For the purpose of research work on standardization of herbal formulations and neutraceuticals a profound knowledge of the important herbs found in India and widely used in Ayurvedic formulation is of utmost importance.
India can emerge as the major country and play the lead role in production of standardized, therapeutically effective ayurvedic formulation. India needs to explore the medicinally important plants. This can be achieved only if the herbal products are evaluated and analyzed using
sophisticated modern techniques of standardization such as UV-visible, TLC, HPLC, HPTLC, GC-MS, spectrofluorimetric and other methods.
Herbal Drug Standardization and Evaluation:- In recent years, there has been great demand for
plant derived products in developed countries. These products are increasingly being sought out as
medicinal products, nutraceuticals and cosmetics. (1) There are around 6000 herbal manufacturers in
India. More than 4000 units are producing Ayurveda medicines. Due to lack of infrastructures, skilled
manpower reliable methods and stringent regulatory laws most of these manufacturers produce their
product on very tentative basis. (2)
In order to have a good coordination between the quality of raw materials, in process materials and
the final products, it has become essential to develop reliable, specific and sensitive quality control
methods using a combination of classical and modern instrumental method of analysis.
Standardization is an essential measurement for ensuring the quality control of the herbal drugs. (3)
"Standardization" expression is used to describe all measures, which are taken during the
manufacturing process and quality control leading to a reproducible quality. It also encompasses the
entire field of study from birth of a plant to its clinical application. It also means adjusting the herbal
drug preparation to a defined content of a constituent or a group of substances with known
therapeutic activity respectively by adding excipients or by mixing herbal drugs or herbal drug
preparations.(4) "Evaluation" of a drug means confirmation of its identity and determination of its
quality and purity and detection of its nature of adulteration.(5)
Standardization of herbal drugs is not an easy task as numerous factors influence the bio efficacy
and reproducible therapeutic effect. In order to obtain quality oriented herbal products, care should be
taken right from the proper identification of plants, season and area of collection and their extraction
and purification process and rationalizing the combination in case of polyherbal drugs.(3)
The Standardization of crude drug materials includes the following steps:-
1. Authentication: - Each and every step has to be authenticated.
a) Stage of collection.
b) Parts of the plant collected.
c) Regional status.
d) Botanical identity like phytomorphology, microscopical and histological analysis
Ayurveda (Sanskrit: आयु�र्वे�द; Āyurveda, "the knowledge for long life"; /ˌaɪ.ərˈveɪdə/[1]) or ayurvedic medicine is a system of traditional medicine native to India and a form of alternative medicine.[2][3] The earliest literature on Indian medical practice appeared during the Vedic period in India,[3] i.e., in the mid-second millennium BCE. The Suśruta Saṃhitā and the Charaka Saṃhitā, encyclopedias of medicine compiled from various sources from the mid-first millennium BCE to about 500 CE,[4] are among the foundational works of Ayurveda. Over the following centuries, ayurvedic practitioners developed a number of medicinal preparations and
surgical procedures for the treatment of various ailments.[5] Current practices derived (or reportedly derived) from Ayurvedic medicine are regarded as part of complementary and alternative medicine.[6]
Safety concerns have been raised about Ayurveda, with two U.S. studies finding about 20% of Ayurvedic treatments contained toxic levels of heavy metals such as lead, mercury and arsenic. Other concerns include the use of herbs containing toxic compounds and the lack of quality control in Ayurvedic facilities.[7][8]
The three doṣas and the 5 elements from which they are composed.
At an early period, Ayurveda adopted the physics of the "five elements" (Devanāgarī: [महा] पञ्चभू�त); Pṛthvī (earth), Jala(water), Agni (fire), Vāyu (air) and Ākāśa (Sky)) — that compose the universe, including the human body.[2] Chyle or plasma (called rasa dhātu), blood (rakta
dhātu), flesh (māṃsa dhātu), fat (medha dhātu), bone (asthi dhātu), marrow (majja dhātu), and semen or female reproductive tissue (śukra dhātu) are held to be the seven primary constituent elements – saptadhātu (Devanāgarī: सप्तधात�) of the body.[9] Ayurvedic literature deals elaborately with measures of healthful living during the entire span of life and its various phases. Ayurveda stresses a balance of three elemental energies or humors: Vāyu vāta (air & space – "wind"), pitta (fire & water – "bile") and kapha (water & earth – "phlegm"). According to ayurvedic medical theory, these three substances — doṣas (literally that which deteriorates – Devanāgarī: द�ष)—are important for health, because when they exist in equal quantities, the body will be healthy, and when they are not in equal amounts, the body will be unhealthy in various ways. One ayurvedic theory asserts that each human possesses a unique combination of doṣas that define that person's temperament and characteristics. Another view, also present in the ancient literature, asserts that humoral equality is identical to health, and that persons with preponderances of humours are proportionately unhealthy, and that this is not their natural temperament. In ayurveda, unlike the Sāṅkhya philosophical system, there are 20 fundamental qualities, guṇa (Devanāgarī: गु�ण, meaning qualities) inherent in all substances.[10] Surgery and surgical instruments were employed from a very early period,[10] Ayurvedic theory asserts that building a healthy metabolic system, attaining good digestion, and proper excretion leads to vitality.[10] Ayurveda also focuses on exercise, yoga, and meditation [11]
The practice of panchakarma (Devanāgarī: प�चकम� ) is a therapeutic way of eliminating toxic elements from the body.[12]
As early as the Mahābhārata, ayurveda was called "the science of eight components" (Skt. aṣṭāṅga, Devanāgarī: अष्टां�गु), a classification that became canonical for ayurveda. They are:[13]
Internal medicine (Kāya-cikitsā) Paediatrics (Kaumārabhṛtyam) Surgery (Śalya-cikitsā) Eye and ENT (Śālākya tantra) Bhūta vidyā has been called psychiatry.[3]
Toxicology (Agadatantram) Prevention of diseases and improving immunity and rejuvenation (rasayana) Aphrodisiacs and improving health of progeny (Vajikaranam)
In Hindu mythology, the origin of ayurvedic medicine is attributed to Dhanvantari, the physician of the gods.[14]
Several philosophers in India combined religion and traditional medicine—notable examples being
that of Hinduism and ayurveda. Shown in the image is the philosopher Nagarjuna—known chiefly for
his doctrine of the Madhyamaka (middle path)—who wrote medical works The Hundred Prescriptions
and The Precious Collection, among others.[15]
[edit] Balance
Hinduism and Buddhism have been an influence on the development of many of ayurveda's central ideas — particularly its fascination with balance, known in Buddhism as Madhyamaka (Devanāgarī: मध्युत्मि�मक).[16] Balance is emphasized; suppressing natural urges is seen to be unhealthy, and doing so claimed to lead to illness.[16] However, people are cautioned to stay within the limits of reasonable balance and measure.[16] For example, emphasis is placed on moderation of food intake,[2] sleep, sexual intercourse.[16]
[edit] Diagnosis
The Charaka Samhita recommends a tenfold examination of the patient.[17]
In addition, Chopra (2003) identifies five influential criteria for diagnosis:[17]
origin of the disease prodrominal (precursory) symptoms typical symptoms of the fully developed disease observing the effect of therapeutic procedures the pathological process'
Ayurvedic practitioners approach diagnosis by using all five senses.[17] Hearing is used to observe the condition of breathing and speech.[9] The study of the lethal points or marman marma is of special importance.[10] Ayurvedic doctors regard physical and mental existence together with personality as a unit, each element having the capacity to influence the others. One of the fundamental aspects of ayurvedic medicine is to take this into account during diagnosis and therapy.
[edit] Hygiene
Hygiene is an Indian cultural value and a central practice of ayurvedic medicine. Hygienic living involves regular bathing, cleansing of teeth, skin care, and eye washing. Daily anointing of the body with oil is also prescribed.[9]
Ayurveda stresses the use of plant-based medicines and treatments. Hundreds of plant-based medicines are employed, including cardamom and cinnamon. Some animal products may also be used, for example milk, bones, and gallstones. In addition, fats are used both for consumption and for external use. Minerals, including sulfur, arsenic, lead, copper sulfate and gold are also consumed as prescribed.[9] This practice of adding minerals to herbal medicine is known as rasa shastra.
In some cases, alcohol was used as a narcotic for the patient undergoing an operation. The advent of Islam introduced opium as a narcotic.[13] Both oil and tar were used to stop bleeding.[9] Traumatic bleeding was said to be stopped by four different methods ligation of the blood vessel; cauterisation by heat; using different herbal or animal preparations locally which could facilitate clotting; and different medical preparations which could constrict the bleeding or oozing vessels. Various oils could be used in a number of ways, including regular consumption as a part of food, anointing, smearing, head massage, and prescribed application to infected areas.[18][page needed]
[edit] Srotas
Ensuring the proper functions of channels (srotas) that transport fluids from one point to another is a vital goal of ayurvedic medicine, because the lack of healthy srotas is thought to cause rheumatism, epilepsy, autism, paralysis, convulsions, and insanity. Practitioners induce sweating and prescribe steam-based treatments as a means to open up the channels and dilute the doshas that cause the blockages and lead to disease.[19]
[edit] History
The mantra Om mani padme hum written on rocks. Chanting mantras has been a feature of ayurveda
since the Atharvaveda, the vedic spiritual text, was compiled.[20]
One view of the early history of ayurveda asserts that around 1500 BC, ayurveda's fundamental and applied principles got organized and enunciated. In this historical construction, Ayurveda traces its origins to the Vedas, Atharvaveda in particular, and is connected to Hindu religion. Atharvaveda (one of the four most ancient books of Indian knowledge, wisdom and culture) contains 114 hymns or formulations for the treatment of diseases. Ayurveda originated in and developed from these hymns. In this sense, ayurveda is considered by some to have divine
origin. Indian medicine has a long history, and is one of the oldest organised systems of medicine. Its earliest concepts are set out in the sacred writings called the Vedas, especially in the metrical passages of the Atharvaveda, which may possibly date as far back as the 2nd millennium BC. According to a later writer, the system of medicine was received by Dhanvantari from Brahma, and Dhanvantari was deified as the god of medicine. In later times his status was gradually reduced, until he was credited with having been an earthly king[9] named Divodasa.[21]
Cataract in human eye – magnified view seen on examination with a slit lamp. Cataract surgery was
known to the physician Sushruta in the early centuries of the first millennium AD, and was performed
with a special tool called the jabamukhi salaka, a curved needle used to loosen the obstructing
phlegm and push it out of the field of vision. The eye would later be soaked with warm butter and
then bandaged.[22]
Underwood & Rhodes (2008) hold that this early phase of traditional Indian medicine identified "fever (takman), cough, consumption, diarrhea, dropsy, abscesses, seizures, tumours, and skin diseases (including leprosy)".[9] Treatment of complex ailments, including angina pectoris, diabetes, hypertension, and stones, also ensued during this period.[5][23] Plastic surgery, couching (a form of cataract surgery), puncturing to release fluids in the abdomen, extraction of foreign elements, treatment of anal fistulas, treating fractures, amputations, cesarean sections, and stitching of wounds were known.[9] The use of herbs and surgical instruments became widespread.[9] The Charaka Samhita text is arguably the principal classic reference. It gives emphasis to the triune nature of each person: body care, mental regulation, and spiritual/consciousness refinement.
Other early works of ayurveda include the Charaka Samhita, attributed to Charaka.[9] The earliest surviving excavated written material which contains references to the works of Sushruta is the Bower Manuscript, dated to the 6th century AD. The Bower manuscript is of special interest to historians due to the presence of Indian medicine and its concepts in Central Asia.[24] Vagbhata, the son of a senior doctor by the name of Simhagupta,[25] also compiled his works on traditional medicine.[9] Early ayurveda had a school of physicians and a school of surgeons.[3] Tradition holds that the text Agnivesh tantra, written by the sage Agnivesh, a student of the sage Bharadwaja, influenced the writings of ayurveda.[26]
The Chinese pilgrim Fa Hsien (ca. 337–422 AD) wrote about the health care system of the Gupta empire (320–550) and described the institutional approach of Indian medicine, also visible in the works of Charaka, who mentions a clinic and how it should be equipped.[27] Madhava (fl. 700), Sarngadhara (fl. 1300), and Bhavamisra (fl. 1500) compiled works on Indian medicine.[24] The medical works of both Sushruta and Charaka were translated into the Arabic language during the Abbasid Caliphate (ca. 750).[28] These Arabic works made their way into Europe via intermediaries.[28] In Italy, the Branca family of Sicily and Gaspare Tagliacozzi (Bologna) became familiar with the techniques of Sushruta.[28]
British physicians traveled to India to see rhinoplasty being performed by native methods.[29] Reports on Indian rhinoplasty were published in the Gentleman's Magazine in 1794.[29] Joseph Constantine Carpue spent 20 years in India studying local plastic surgery methods.[29] Carpue was able to perform the first major surgery in the western world in 1815.[30] Instruments described in the Sushruta Samhita were further modified in the Western World.[30]
[edit] Current status
A typical ayurvedic Pharmacy, Rishikesh.
[edit] India
Up to 80% of people in India use either Ayurveda or other traditional medicines.[31]
In 1970, the Indian Medical Central Council Act which aims to standardize qualifications for ayurveda and provide accredited institutions for its study and research was passed by the Parliament of India.[32] In India, over 100 colleges offer degrees in traditional ayurvedic medicine.[11] The Indian government supports research and teaching in ayurveda through many channels at both the national and state levels, and helps institutionalize traditional medicine so that it can be studied in major towns and cities.[33] The state-sponsored Central Council for Research in Ayurvedic Sciences (CCRAS) has been set up to research the subject.[34] To fight biopiracy and unethical patents, the Government of India, in 2001, set up the Traditional Knowledge Digital Library as repository of 1200 formulations of various systems of Indian medicine, such as ayurveda, unani and siddha.[35][36] The library also has 50 traditional ayurveda books digitized and available online.[37]
Central Council of Indian Medicine (CCIM) a statutory body established in 1971, under Department of Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homoeopathy (AYUSH), Ministry of Health and Family Welfare, Government of India, monitors higher education in ayurveda.[38] Many clinics in urban and rural areas are run by professionals who qualify from these institutes.[32]
[edit] Sri Lanka
The Sri Lankan tradition of Ayurveda is very similar to the Indian tradition. Practitioners of Ayurveda in Sri Lanka refer to texts on the subject written in Sanskrit, which are common to both countries. However, they do differ in some aspects, particularly in the herbs used.
The Sri Lankan government has established a Ministry of Indigenous Medicine (established in 1980) to revive and regulate the practice of this indigenous medical science within the country [39]
The Institute of Indigenous Medicine (affiliated to the University of Colombo currently offers undergraduate, postgraduate, and MD degrees in the practice of Ayurveda Medicine and Surgery, and similar degrees in unani medicine. [40]
There are currently 62 Ayurvedic Hospitals and 208 central dispensaries in the public system, and they served almost 3 million people (approximately 11% of Sri Lanka's total population) in 2010. In total there are currently approximately 20,000 registered practitioners of Ayurveda in the country.[41][42]
Many Sri Lankan hotels and resorts offer Ayurveda themed packages, where guests are treated to a wide array of Ayurveda treatments during their stay.
[edit] Outside South Asia
Due to different laws and medical regulations in the rest of the world, the unregulated practice and commercialization of ayurvedic medicine has raised ethical and legal issues; in some cases, this damages the reputation of ayurvedic medicine outside India.[43][44][45]
[edit] Journals
There are two PubMed-indexed journals focusing on Ayurveda, the Journal of Ayurveda and Integrative Medicine (JAIM),[46] and The International Journal for Ayurveda Research (IJAR)[47]
In studies in mice, the leaves of Terminalia arjuna have been shown to have analgesic and anti-
inflammatory properties.[48]
As a traditional medicine, many ayurveda products have not been tested in rigorous scientific studies and clinical trials. In India, research in ayurveda is largely undertaken by the statutory body of the Central Government, the Central Council for Research in Ayurveda and Siddha (CCRAS), through a national network of research institutes.[49] A systematic review of ayurveda treatments for rheumatoid arthritis concluded that there was insufficient evidence, as most of the trials were not done properly, and the one high-quality trial showed no benefits.[50] A review of ayurveda and cardiovascular disease concluded that the evidence for ayurveda was not convincing, though some herbs seemed promising.[51]
Two varieties of Salvia have been tested in small trials; one trial provided evidence that Salvia lavandulifolia (Spanish sage) may improve word recall in young adults,[52] and another provided evidence that Salvia officinalis (Common sage) may improve symptoms in Alzheimer's patients.[53] Many plants used as rasayana (rejuvenation) medications are potent antioxidants.[54] Neem appears to have beneficial pharmacological properties.[55]
[edit] Safety
Rasa shastra, the practice of adding metals, minerals or gems to herbs, is a source of toxic heavy metals such as lead, mercury and arsenic.[7] Adverse reactions to herbs due to their pharmacology are described in traditional ayurvedic texts, but ayurvedic practitioners are reluctant to admit that herbs could be toxic and the reliable information on herbal toxicity is not readily available.[56]
According to a 1990 study on ayurvedic medicines in India, 41% of the products tested contained arsenic, and 64% contained lead and mercury.[31] A 2004 study found toxic levels of heavy metals in 20% of ayurvedic preparations made in South Asia and sold in the Boston area, and concluded that ayurvedic products posed serious health risks and should be tested for heavy-metal contamination.[57] A 2008 study of more than 230 products found that approximately 20%
of remedies (and 40% of rasa shastra medicines) purchased over the Internet from both US and Indian suppliers contained lead, mercury or arsenic.[7][58][59]
Ayruvedic proponents believe that the toxicity of these materials is reduced through purification processes such as samskaras or shodhanas (for metals), similar to the Chinese pao zhi, although the ayurvedic technique is more complex and may involve prayers as well as physical pharmacy techniques. However, these products have nonetheless caused severe lead poisoning and other toxic effects.[7][58]
Due to these concerns, the Government of India ruled that ayurvedic products must specify their metallic content directly on the labels of the product,[8] but, writing on the subject for Current Science, a publication of the Indian Academy of Sciences, M. S. Valiathan noted that "the absence of post-market surveillance and the paucity of test laboratory facilities [in India] make the quality control of Ayurvedic medicines exceedingly difficult at this time.[8]
Indian herbal market to grow by 20%ASHOK B SHARMA
Posted: Friday, Apr 04, 2008 at 1834 hrs ISTTags:
New Delhi, April 4:: Indian herbal market is registering an extremely significant growth and is likely to reach Rs.14,500 crore (Rs 145,000 million) by 2012 and exports to Rs.9,000 crore (Rs 90,000 million) with a CAGR of 20% and 25% respectively, according to findings of the Associated Chambers of Commerce and Industry of India (Assocham).
In a Chamber Study on `Herbal Industry Biz Potential' has revealed that currently, the Indian herbal market size is estimated at Rs.7000 crore (Rs 70000 mn) and over Rs.3600 crore (Rs 36000 mn ) of herbal raw materials and medicines are exported by India.
Assocham has organized an International Herbal Expo in Delhi on Friday in which 50 international buyers are participating
The reasons cited for the herbal industry experimental growth comprises setting up of Herbal farm clusters by the government for improving quality of drugs and promotion of exports, doubling the cultivation of medicinal plants by converting existing farmland, continuous focus for R&D on product and process development and effective marketing of herbal products, the study said.
The study also revealed that out of 700 plant species commonly used in India, only 20% were earlier being cultivated on commercial scale and 90% of medicinal plant used by the industries are collected from the wild.
On the whole, India is stated to have 45,000 plant species (nearly 20% of the global species) occurs in the Indian sub-continent. Out of these, about 4,500 species of both higher and lower plant groups are of medicinal value.
The study, however, said that the major hurdle for cultivating medicinal and aromatic plants as a sustainable agricultural profession were the lack of organized and regulated markets in India. The regulated production on
scientific lines, effective enforcement of licensing system and setting up of Export Promotion Zones (EPZ) in select states will push up exports of herbal material and medicines.
Apart from that, the Indian herbal drug exporters face the stringent quality norms imposed by the EU through the Traditional Herbal Medicinal Products Directive (THMPD), Food Supplement Directive (FSD) and these directives also encouraged the high quality products and subsequently the unorganized sectors sub-standard products are rejected by them.
India followed by China is the largest producer of medicinal plants, having more than 40% of global diversity. The states which are major producer of herbal plants having the highest medicinal value include Gujarat, Rajasthan, Haryana, Tamil Nadu, Andhra and the Himalayan Range.
According to Assocham estimates, over 70% of the plant collections involve destructive harvesting because of the use of parts like roots, bark, wood, stem and the whole plant in case of herbs. This poses a definite threat to the genetic stocks and to the diversity of medicinal plants if biodiversity is not sustainably used.
Around 70% of India's medicinal plants are found in tropical areas mostly in the various forest types spread across the Western and Eastern ghats, the Vindhyas, Chotta Nagpur plateau, Aravalis and Himalayas. Although less than 30% of the medicinal plants are found in the temperate and alpine areas and higher altitudes they include species of high medicinal value. Macro studies show that a larger percentage of the known medicinal plant occur in the dry and moist deciduous vegetation as compared to the evergreen or temperate habitats.
"This will be particularly so because in the identified countries, urge for swadeshi (indigenous) herbal medicines has been rising due to their quality ingredients, availability factor and price competitiveness with virtually little side effects. Secondly, swadeshi (indigenous) herbs and medicines meet all the WHO prescribed standards and norms and thus encounter no restrictions in overseas markets to have instant acceptability from its takers", the study said.
The medicines that have established export demand in economies of scale and produced with international quality norms include psyllium husk, sema leaves & pods, sandalwood chips and dust, Jojoba seeds, psyllium seeds, pyrethrum, basil, hyasop, rosemary safe, svory, galangal rhizonmes and roots. The application of these medicines is multifaceted and cure even serious aliments with little precautions and that's why are in great demand. India's share in medicinal plant export in global trade is just about 2.5% against 13% of China.
The paper highlights that India has 15 Agroclimatic zones, 4700 different plant species and 15000 medicinal plants The Indian Systems of Medicine have identified 1500 medicinal plants, of which 500 species are mostly used in the preparation of drugs.