Medicinal Plants – Source of New Pharmacophore for Drug Discovery and Development

Modern drug development is a lengthy and expensive process, which requires an investment of over $1.8 – 2.0 billion, a large interdisciplinary team, and years of studies. Unfortunately this situation has out-resourced and out-numbered the pharmaceutical R&D and academic institutions of developing nations. As a result, several diseases, affecting the lives of poor population remain untreated. This situation demands a major search of natural products using the indigenous knowledge. During this presentation, results of our studies on discovery natural products as potential drug candidates at low cost will be presented.

Urolithiasis is the most common disease of urinary tract affecting up to 15% of world population. To explore the possible antiurolithic effect of natural products, we have evaluated the ethanolic extract Bryophyllum pinnatum and its constituent (caffeic acid) for in vitro calcium oxalate crystallization and in vivo ethylene glycol induced urolithiasis rat modal. The results were analyzed by histopathological examination and checking the expression of kidney stone related genes i.e. prothrombin fragment-1, osteopontin, Tamm Horsfall, and bikunin from kidney tissues and 24h urine samples of experimental rats by RT and real time PCR. Results of these studies showed the preventive as well as curative effect of B. pinnatum and caffeic acid.

Similarly due to high prevalence of candidiasis and leishmaniasis in our region and associated morbidity, we have carried out a systemic study based on our indigenous knowledge. We have isolated anticandidiasis and antileishmanial agents from natural origin and conducted in vitro and in vivo studies on Physalis minima and Trachyspermum ammi. The in vivo results showed no cytotoxicity and healing of lesions. We have also conducted clinical trials on 110 leishmaniasis patients by applying new ointment based formulations of P. minima topically. The results unambiguously established the safety, efficacy, and cost effectiveness of the P. minima extracts-based topical gel against cutaneous leishmaniasis.