Importance of Plant Conservation for Future Drug Discoveries

Text & Photos by Dr. Pankaj Chetia


Human civilization is still dependent on plant resources for combating different ailments..


Houttuynia cordata


“All plants are medicinal”. Well, these are not my words! This was the version of great ancient Indian saint cum physician Sushruta who once listed around 700 medicinal plants and their usage in curing around 1120 ailments. The statement which was put forwarded centuries ago is still relevant. Human civilization is still dependent on plant resources for combating different ailments. Different plants are reservoirs of different phytochemicals. These phytochemicals may be highly medicinal or sometimes even toxic or allergenic. Structures of some of these phytochemicals may be really new to us and these may have tremendous medicinal importance. These phytochemicals may lead to the discovery of novel and effective drugs against different diseases.


As we all know, north east India is highly rich in biodiversity, ethnic diversity and so is rich in medicinal Plants. Different ethnic communities have their indigenous medicinal knowledge which is mainly plant based. Although modern healthcare system is gradually replacing the indigenous systems, medicinal plant based healthcare systems are still prevalent in most of the remote areas and the entire region as a whole. Natural product researchers are engaged in identification and isolation of bioactive principles from these traditionally used medicinal plants. If we see the origin of several lifesaving drugs like Artemisinin, Taxol, Quinine etc., the most important fact is that all these are of plant origin. Although many of these plant derived compounds can be synthesized in the laboratory, a section of these can’t be synthesized and can only be extracted from the plant itself.


Rauvolfia serpentina


Taxol is one such anticancer drug, which can’t be synthesized in the laboratory so far and is extracted only from the bark of Taxus baccata L., Taxus wallichiana Zucc. and other Taxus spp. Because of this, these Taxus plants are being overexploited and being smuggled which has become a major threat. This is just an example. Assam, and the entire north east India as a whole, is rich in medicinal plants. Many of these plants are overexploited for different purposes in an unsustainable manner. Because of overexploitation and also because of our negligence, many of these important medicinal plants are getting disappeared day by day.


In Assam, we find many medicinal plants of tremendous importance in our backyard itself. Rauvolfia serpentina (L.) Benth. ex Kurz, a prioritised medicinal plant of National Medicinal Plant Board, Govt. of India grows naturally in our soil. Many important phytochemicals viz. Reserpine, Rauvolfine, Rauvolfinine, Serpentine, Serpentinine, Ajmalicine etc. are extracted from this plant.


Andrographis paniculata (Burm.f.) Nees is another very important medicinal plant which is known for its extreme bitter taste and is commonly known as “Kalmegh”. It is known for its traditional usage as analgesic, antidiabetic, hepatoprotective, immunostimulant, antimalarial, antimicrobial, antidiarrhoeal, antioedema and anticancer activities. Many phytochemicals such Andrographolide, Andrgraphine, Neoandrographolide, Panicoline etc. have been reported from this plant.


Thunbergia alata


In addition, many important medicinal plants such as Houttuynia cordata Thunb. , Tinospora sinensis (Lour.) Merr., Boerhavia diffusa L., Peperomia pellucida (L.) Kunth, Vitex negundo L., Cheilocostus speciosus (J.Koenig) C. D. Specht, Scoparia dulcis L., Azadirachta indica A.Juss., Alternanthera sessilis (L.) R. Br. ex DC., Justicia adhatoda L., Phlogacanthus thyrsiflorus Nees, Ocimum spp. etc. are very common and are widely used for different ailments.


Although these medicinal plants are used traditionally in raw form or as decoction or in other formulations, the phytochemicals extracted from these plants are of tremendous medicinal value for modern medicine system. Considering their medicinal potential, many of these plants are nowadays being widely cultivated. Curcumin which is a known anti-inflammatory, anti-tumor and antioxidant molecule is extracted from Curcuma longa L. Initially this plant was cultivated only for preparing haldi (a spice or colouring agent). However, this plant is nowadays widely cultivated for Curcumin extraction also.


Considering the importance of these medicinal plants and phytochemicals in drug discovery researches, several digital databases have been created. Dr. Duke’s Phytochemical and Ethnobotanical Database is one such example which stores the ethnobotanical usages of different medicinal plants and phytochemicals reported from these plants. If we see the plant based medicines, around 40% of all drugs are occupied by them only. Many phytochemicals are used as drug in their native form, however many others are used as source molecule to produce derivatives with better therapeutic potentials. These phytochemicals are active components of many allopathic medicines.


Although some of these plants are cultivated for extraction of different phytochemicals, many plants are still being collected from their natural habitat itself for the same purpose. The overexploitation of these plants in natural habitat has posed a threat of their extinction. Moreover, ex situ conservation of these plant resources may not be successful always. Therefore it’s high time to conserve the medicinal plant resources.


About the Author:



Dr. Pankaj Chetia is Assistant Professor in the Department of Life Sciences, Dibrugarh University.

You can reach him at chetiapankaj@gmail.com




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