PHARMACOGNOSTICAL STUDY The microscopic method allows more detailed examination of a drug which can be used to identify the organized drugs by their known histological characters. It is mostly used for qualitative evaluation of organized crude drugs in the entire and powdered form of the drugs.
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PHARMACOGNOSTICAL STUDY
The microscopic method allows more detailed examination of a drug which can be used to identify the organized drugs by their known histological characters. It is mostly used for qualitative evaluation of organized crude drugs in the entire and powdered form of the drugs.
Chapter 4 Pharmacognostical Study
Pharmacognostical and pharmacological evaluation of some medicinal plants Page 36
CHAPTER 4
PHARMACOGNOSY: MORPHOLOGICAL, ANATOMICAL AND
PROXIMATE ANALYSIS OF LEAF AND STEM OF
AEGLE MARMELOS CORREA, MORINGA OLEIFERA LAM, PAEDERIA FOETIDA LINN
AND MELASTOMA MALABATHRICUM LINN
4.1 Introduction
The microscopic method allows more detailed examination of a drug which can be used to identify the
organized drugs by their known histological characters. It is mostly used for qualitative evaluation of
organized crude drugs in the entire and powdered form of the drugs. Ash values and extractive values
are used for the study of physical properties.
Arrangement of plant in groups and subgroups is commonly spoken as classification. The
foundation of taxonomy is mainly laid down by the International Code of Botanical Nomenclature,
binomial nomenclature mainly deals with designing a plant in terms of its genus and species name.
A large number of plant families have certain distinguishing characteristics that permits crude
drug from these families to be studied at one time. It is a scientific way of naming, describing and
arranging the plants in an orderly manner.
4.2 Pharmacognostical studies of Aegle marmelos (Corr.)
4.2.1 Materials and methods
Material and method procedure for the Aegle marmelos (Corr.), Moringa oleifera (Lam.), Paederia
foetida (Linn.) and Melastoma malabathricum (Linn.).
4.2.2 Collection of plant material
Aegle marmelos (Corr.) and Moringa oleifera (Lam.) were collected from Herbal garden, Department of
pharmaceutical sciences, Faculty of Health Sciences, SHIATS, Allahabad. Paederia foetida (Linn.) and
Melastoma malabathricum (Linn.) were collected from the Herbal garden, Department of Life Sciences,
Dibrugarh University, Dibrugarh, Assam.
4.2.3 Authentication of the plant materials
Aegle marmelos (Corr.) (SIP/HD/054/17) and Moringa oleifera (Lam.) (SIP/HD/054/18) were
authenticated by Dr. Imran kazmi, Pharmacognosit, Siddhartha Institute of Pharmacy, Dehradun, India
and a specimen voucher has been deposited in the herbarium of the department for further reference.
Paederia foetida (Linn.) and Melastoma malabathricum (Linn.) were collected from the Herbal garden,
Department of Life Sciences, Dibrugarh university, Dibrugarh, Assam and authenticated by Botanical
survey of India, Shillong, India and a specimen voucher was submitted has been deposited in the
department for further references.
Chapter 4 Pharmacognostical Study
Pharmacognostical and pharmacological evaluation of some medicinal plants Page 37
4.2.4 Evaluation of drugs
Evaluation means of confirmation of the purity and identify the quality. The main basis of evaluation of
drugs is to identify quality and determine the purity. The identity of the drug is established by actual
collection of the drugs from a plant or animal which has been correctly identified for which “drug
gardens” are often established for the authenticity of the plants. Another method of identification is to
compare the drug sample with a published description of drug and with authentic drug sample (Mitra et
al., 2004).
The evaluation of drugs includes the following methods:
1. Organoleptic
2. Microscopic
3. Biological
4. Chemical
5. Physical
4.2.4.1 Macroscopic/ Organoleptic Evaluation of the drugs
4.2.4.1.1 Organoleptic studies
Organoleptic (i. e., impression on the organs) refers to evaluation by means of the organs of sense and
includes the microscopic appearance and the odor, taste etc. of the drugs. The macroscopic
characteristics of the drug include,
Size and shapes,
Colour and external marking,
Fracture and internal colour,
Odour and taste.
4.2.4.1.2 Microscopic Studies
The uses of the microscope in the Pharmacognosy have been made since 1847. The microscope is not
only essential in the study of adulterants in powdered plants and animal drugs, but it is also
indispensable in the identification of pure powder drug.
Organoleptic studies of the many drug plants, the microscopic characters are very prominent. In
order to study these characters (also in order to differentiate it from the common adulterants) a good
laboratory technique is essential. Arrangement must be made to prepare the drug for section cutting.
Dried drugs must be softened by exposing them in moist atmosphere or by soaking or boiling them in
water. The following aims should be kept in mind:
The determination of the size, shape and relative position of the different cells and tissues.
The determination of the chemical nature of the cell walls.
Chapter 4 Pharmacognostical Study
Pharmacognostical and pharmacological evaluation of some medicinal plants Page 38
The determination of the form and chemical nature of the cell walls.
In the general idea of distribution of tissues can be obtained by the examination of transverse, radial and
tangential longitudinal sections. First, sections should be mounted in water or dilute glycerin. Then the
section should be cleaned by chloral hydrate or 50% KOH (either aqueous or alcoholic) which dissolve
starch, proteins, chlorophylls, resins, volatile oils etc and causes shrunken cells to expand. After
cleaning, defatting or bleaching, the sections are stained with suitable reagents.
4.2.5 Anatomical studies of plant materials
4.2.5.1 Specimens preparation
Leaves and stem of the Aegle marmelos (Corr.), Moringa oleifera (Lam.), Paederia foetida (Linn.) and
Melastoma malabathricum (Linn.) obtained from a living specimen of the plant were fixed in FAE
(1:1:18) (formalin – 5ml + Acetic acid -5ml + 70% ethyl alcohol-90 ml) for 48-72 h. The specimens of
the plant material were dehydrated with a graded series of tertiary butyl alcohol (Sass JE, 1940).
Infiltration of the specimens was carried by gradual addition of paraffin wax (melting point 58°- 60°C)
until TBA solution attains super saturation. The specimens were cast into paraffin blocks.
4.2.5.2 Sectioning
All types of plant material can be sectioned by hand with the use of the correct razor. Hand sectioning is
a quick method of obtaining a few sections or for identification of specimens (Purvis et al., 1969). A
wedge shaped or planoconcave razor is required to cut hand sections of timber and these sections must
consist only of a very small portion of the surface. The material should be held firmly between the
fingers and thumbs of one hand, with the end of material supported by the fourth finger. The stem of the
razor should be held between the thumb and the first two fingers, with the handle at right angles to the
blade, gripped between the second and third fingers. In this way both the material and the razor are held
firmly. When cutting sections of any types of material, both the specimen and the razor must be kept
wet. If cutting preserved material, the razor must be kept flooded with 70% alcohol, but if cutting fresh
material water is substituted. On no account should the specimen be allowed to dry out. The sections can
be removed from the razor with a finger or a soft brush and placed in either 70% alcohol or water. Pin
dishes and specimen tubes containing 70% alcohol are useful for holding and storing sections. Soft
haired brushes, size 3 and 5, or section lifters are useful to transfer sections from one liquid to another.
4.2.5.3 Photomicrographs
Microscopic descriptions of tissues are supplemented with micrographs wherever necessary.
Photographs of different magnifications were taken with Canon Power shot digital camera (S-80) and
Leica microscope (Photographic Attachment). For normal observations bright field was used. For the
study of crystals, starch grains and lignified cells, polarized light was employed. Since these structures
Chapter 4 Pharmacognostical Study
Pharmacognostical and pharmacological evaluation of some medicinal plants Page 39
have bi-refringent property, under polarized light they appear bright against a dark background.
Magnifications of the figures are indicated by the scale- bars. Descriptive terms of the anatomical
features are as given in the standard plant anatomy textbooks.
4.2.6 Determination of proximate analysis
The purpose of standardization of medicinal plant products is to ensure therapeutic efficacy.
Standardization is essentially a measure for ensuring the quality control of the herbal drugs. Quantitative
standards are a number of standards numerical in nature, which can be applied to the evaluation of crude
drugs either in the whole or the powdered conditions. These are standards for identity, purity and quality
of drugs. Purity depends upon the absence of foreign matter, while quality refers essentially to the
concentration of the active constituents in the drugs that make it valuable to medicine.
4.2.6.1 Determination of ash value
The residue remaining after incineration of the crude drug at 450oC is designated as ash. The residue
obtained after the incineration of crude drug is following types. One is physiological type which is
obtained directly from the plant and other one non physiological obtained from the sand, silica and
extraporeneous matters. It may also include inorganic matter added for the purpose of adulteration.
Hence, an ash value determination furnishes the basis for judging the identity and cleanliness of any
drug and gives information relative to its adulteration/contamination with inorganic matter, thus ash
values are helpful in determining the quality and purity of the drug. The ash remaining following
ignition of medicinal plant materials is determined as total ash, acid insoluble ash, water soluble ash and
sulphated ash.
4.2.6.2 Determination of total ash
Accurately weighed 2g of plant powder was incinerated in crucible at a temperature not exceeding
450oC in a muffle furnace, until ash free from carbon was obtained. It was then cooled in desiccators,
weighed and percentage of ash was calculated with reference to the air-dried drug (Trease and Evans,