IDENTIFICATION OF RAW DRUGS
Dr. Prashant Kumar Jha
Head, Quality Control Laboratories,
ALN Rao Memorial Ayurvedic Medical College, Koppa
Prof. (Dr.) T. N. Pandya
Head, Department of Dravyaguna,
IPGT & RA, Gujarat Ayurved University, Jamnagar
A substance used for medicine and still not processed or subjected to analysis is raw drug. This substance may be of inorganic or organic origin. The major portion of drugs used in Ayurveda is covered by those of organic origin and especially of plant origin from them. The drugs of organic origin are categorized in organized and unorganized based on presence or absence of cellular structure respectively. Further those of herbal drugs are classified in cryptogamous and phanerogamous by means of source of origin. Cryptogamous covers algae, fungi, lichens, bryophytes and pteridophytes; they inclusively cover around 10% of total consumption of herbal drugs. The remaining 90% is shared by angiosperm and gymnosperm being 89% and 1% respectively.
According to an estimate, out of over 2,50,000 plant species, 35,000 are used medicinally. India alone is using over 6,000 plants for medicinal purpose and out of this around 2,400 plants are used in various indigenous systems of medicines. The major portion is encompassed by Ayurveda using around 1,550 plants. According to various sources roughly 1,000 plants are having trade for various medicinal purposes. The total trade in European countries alone reaches above 6 million dollars. Root and rhizomes share the biggest portion of this trade followed by fruits, whole plants, stems, leaves etc. As the drug has both commercial and medicinal aspects involved with health of general beings, true identification for standard drugs automatically becomes important.
Need of Identification: Identification is process of recognition or genuine entity of individuals; even they may be the plants or herbal drugs or any living organism. Identification turns important when commercial aspects are postulated. Knowingly or unknowingly, adulteration has been part of herbal trading. Some of these admixing are totally different from genuine by means of compositions and medicinal effects too. Malva rotundifolia and Merremia species were found selling by name of Brahmi (Bacopa monnieri). The leaves of these adulterants are only similar to officially allowed substitute of Brahmi i.e., Centella asiatica. Cyperus stoloniferus is found being sold in Mumbai market by name of Jatamansi, the genuine one being Nardostachys jatamansi. Similarly various adulterants are in market for different plant drugs. Once identification of each drug is set in form of monograph, adulteration can be easily judged by buyers. Even exhausted drugs of essential oil containing drugs like clove with less volatile oil, can also be checked.
Techniques of Identification: Techniques for identification of raw drugs are well mentioned and found Pharmacopoeia of any nation and WHO (World Health Organization) guidelines under following headlines as:
1. Organoleptic evaluation
2. Macroscopic evaluation
3. Microscopic evaluation
4. Chemical evaluation
Organoleptic evaluation: It involves the application of sensory organs. In these tests the shape and size, external colour and markings, fracture, texture or feel, internal colour and marking, odour, and taste are noted like:
Fracture : Short, fibrous, granular, splintery, laminated, mealy etc.
Odour : Aromatic, camphoraceous etc.
Taste : Better, sweet, pungent, numbing etc.
Macroscopic evaluation: It involves the comparison of exo-morphological characters that are visible with the naked eye or under low magnification microscope with descriptions of the plant or botanical drug in floras or standard monographs of drugs in pharmacopoeia as presence of marks, lenticels, ridges, gyri etc.
Microscopic evaluation: It is carried out in following steps:
1. Detailed tissue structure by means of various ways of sectionings like TS, LS etc.
2. Localization of metabolites,
3. Powder characters.