Includes the study of traditional concepts or methods for distinguishing between various plant parts such as bark, leaves, seeds, tubers, etc. and indigenous ways of
distinction, if any, between the quality of such products from collections indifferent seasons or situations.
Most of the drug plants are wild and only a few of them have been cultivated. Studies of medicinal plants based on ancient literature and its investigation in the modern light is known as “ethnology”.
In India, the history of use of ayurvedic medicines is about 7000 years ago. The first evidences about ayurvedic medicines are present in “Rigveda (5000 B.C.). Thereare 67 plants mantioned in “Rigveda” which have medicinal importance.
InIndian system of medicine the old ancient literature like“Charak–Samhita” (700 B.C.) and “Sushruta–Samhita” (2000 B.C.) have knowledge of about 2370 plants of ayurvedic importance, some well known examples are Ocimum sanctum L. and Ficus religiosa L. etc.
Such information is not compiled in systematic manner and vast amount of information exists only in the folklore and has not been studied systematically. (Sharmaand Goswami, 1992).
India has rich biodiversity consisting of around 4000 medicinal plants. (Anonymous, 1972,Anonymous, 1986). A large number of these plants are utilized in the herbal drugs (Jain, 1987, Jain and Defellips, 1991). Medicinal plants have greatimportance in providing health care to about 80 percent of the population(Mehrotra, 1986).
It hasbeen realized all over the world that much valuable knowledge about uses of plants including medicinal uses is still endemic among many tribal or rural human societies. According to WHO report, several diseases of modern times are generally life style diseases. The ayurvedic system of medicine not only provides cure for a large number of general and chronic diseases but it also strengthens the inner body strength.
Although the use of allopathic medicines have quick results against diseases but these drugs have many side effects on our body.
Although several crude drugs have been reported from various elements but their correct identification and determination of pharmacognostical properties, biochemical nature, morphological, anotomical, physiological, molecular biological and biotechnological studies etc. are lacking. (Basu and Nath, 1936, Tiwari and Minocha, 1978).
Recently,great interest in the above given studies of herbal drugs and traditional remedies is indicated world wide and there has been an upsurge in the scientific investigations in this area. (Satyavati et al., 1976, Jain and Defellips, 1991).
Some information on the ethnobotanical aspect of medicinal plants has also been compiled. (Mitraand Jain, 1991). The bio-transformation studies could help in improving the yield potential.
There is a big trade in the herbal drugs. However, due to non–availability or scarce supply of some genuine important crude drugs, their substitutes or adulterants with a similar appearance have entered the market, but these material do not possess the desired medicinal properties.
Also,at times, different herbal drugs have the same drug has different names indifferent localities and regions of the country.
In order to detect spurious crude drugs and to avoid confusion in vernacular namesof medicinal plants, the area of pharmacognosy needs a thrust supported by adequate resources to investigate scientifically the large number of drugs in use in indigenous medicine. (Mehrotra, 1986).
Reviews on the pharmacognostical studies on Indian medicinal plants have appeared from time to time (Mitra and Jain, 1991).
As many as 3226 out of4752 communities in India representing 70% of the population are dependent on the traditional plant based medicines (Gadgil and Rao, 1993). The tribal communities use over 500 speciesof plants for medicinal purposes (Pushpagadan, 1994).
Rienacker in his article“The future of medicines” says a new type of medicinal scientist are appearing on the scene who no longer regard diseases mechanically as local phenomena but as symptoms resulting from a general state of disorganizations and disharmony(Weiss and Fintelmann, 2000).
Detailed investigation on pharmacognostical characterization of these crude drugs are needed to make their effective application possible (Mooss, 1953, Rastogi and Mehrotra, 1991).
Investigations in the field of pharmacognosy and pharmacology can supply valuable information onmedicinal plants with regard to their availability, botanical properties,methods of cultivation, collection, storage, commerce and therapeutic uses(Kumar, 1992).
In ayurvedic system of medicines a large number of plants are employed for the treatment of several diseases like cancer (Jain and Defellips, 1991; Sharma and Kumar, 2000), depression and other nervousdisorders (Mishra and Kumar, 2000),diabetes (Raghunathan and Mitra, 1982; Gupta and Kumar, 2002), rheumatism(Sanghi and Kumar, 2001), Leprosy (Sanghi and Kumar, 2002), skin disease(Saxena and Kumar, 2002) Urinary stone track disease (Mishra and Kumar, 2001)hepatic disease (Sharma and Kumar, 2001), disease of digestive system(Choudhary and Kumar, 2001), Malaria(Yadav and Kumar, 2002) paralysis (Sharmaand Kumar, 2001).
Aloe, a member of the Lilliaceae family is a tropicalto subtropical plant with more than 300 species known, mostly indigenous to Africa for which systematic information in relation to chemotaxonomy has also been attempted. It is one of the most popular natural sources for a range of home remedies in use today.
The major component of the leaf mass is the gel from the parenchymatous cells consisting mainly of polysaccharides, while theacetylated mannose sugar is the major bioactive component.
The species of Aloe have been used for centuries for their laxative, anti inflammatory, immunostimulant, antiseptic,wound and burn healing, anti-ulcer and anti-tumor activities. There are reportson the antidiabetic activity of Aloe extracts also.
Medicinalplants with anti-tumour potential are listed below:
Antitumour triterpenoidsderived from Celastrus hindsii.
Medicinal plants withanti-HIV potential
Acquiredimmunodeficiency syndrome (AIDS) has been a serious life-threatening healthproblem since 1981 and is the most quickly spreading disease of the century.
On account of recentreports of who and Unaids, at the end of 2001, an estimated 40 million people globally were living with HIV, out of them about 22million people had died.
Plants with anti-HIVpotential are listed below:
(1) Acer okomotoanum
(2) Artemisia annua
(3) Croton tiglium
(4) Curcuma longa
(5) Glycyrrhiza lepidata
(6) Polyalthia suberosa
(7) Phyllanthus myrtifolius.
Out of an estimated 250,000 higher plants, less than1% has been screened pharmacologically and very few in regards to AIDS.Therefore, it is prudent to look for options in herbal medicine for AIDS as well. It should be noted that many of the anti-HIV drugs currently used in chemotherapy either are derived directly from natural products or are synthetic based on natural product models. Natural product derived active compounds serve as important lead molecules as demonstrated in the case of the development of calanolides. The rapid evolution of new anti-HIV clades and drug resistant variants in AIDS patients, as well as resurgence of other infectious diseases,such as drug resistant tuberculosis and hepatitis requires the development of innovation but reproducible technology targeting the critical elements for drug discovery and development. The goals of medicine no matter to which group it belongs i.e. the welfare of the patient. One can look towards a future of integrated medicine and hope that research in alternative medicine will help to identify what is safe and effective rather than marginalizing, unorthodox medical claims and findings.
Himanshu Sharma and Ashwani Kumar (2011)Pharmacognostical studies on some selected medicinal plants: Plants for human health and welfare. Lambert Academic Publishers, Germany. pp 229