Antihyperglycemic and Antidyslipidemic Agents
Obesity, insulin resistance (Diabetes) and dyslipidemia are generally found as a part of a complex mixture of metabolic abnormalities collectively known as the metabolic syndrome. As a part of our natural products program we identified few lead molecules from Indian medicinal plants for metabolic disorder diseases for example Aegeline, an alkaloidal amide isolated from the leaves of Aegle marmelos (bael), exhibits the potent lipid lowering activity and mild antihyperglycemic activity; 4-hydroxyisoleucine an unusual amino acid from Trigonella foenum graecum (methi seeds) exhibits dual activity (antidyslipidemic and antihyperglycemic). terpenoid derivatives (a-amyrin and lupeol) exhibits antihyperglycemic activity. Modified furanoflavonoids (pseudosemiglabrin and semiglabrin) isolated from Indigofera tinctoria showed good lipid lowering activity.

Antihyperglycemic and Antidyslipidemic Agents
The protozoan parasite Leishmania cause a broad spectrum of diseases ranging from cutaneous healing skin lesions caused by L. major to a fatal visceral form called kala azar caused by L. donovani. We identified an orally active antileishmnaial agent i. e., Peganine from the seeds of Peganum harmala. It induces apoptosis- like cell death in L. donovani. The binding interactions between peganine and DNA topoisomerase I in molecular modeling studies (docking) and experimental studies suggested that the apoptosis like cell death appears to be due to L. donovani’s topoisomerase I inhibition. We also obtained few natural chromenodihydrochalcones, which exhibits antileishmanial activity in in-vitro studies. We synthesized several analogues of these chalcones and studied their in-vitro and in-vivo antileishmanial activity.

Anticancer taxanes
In continuation of our drug discovery program on anticancer agents we isolated 2-deacetoxytaxinine J (2-DAT-J) in reasonably good yield (0.1%) from the Indian T. baccata (ssp. wallichiana). It has effects on the Ca2+ induced microtubule depolymerization. 2-DAT-J is a powerful inhibitor of P-glycoprotein (P-gp) activity, acting as efficient reversing agent in multi-drug resistant (MDR) cancer cells.

Anti HIV coumarins
Recently we initiated research work on the calanolide class of compounds, which are known for their HIV reverse transcriptase inhibiting activity. We isolated few coumarins from Calophyllum inophyllum to develop anti HIV and anti TB compounds.

We also isolate novel compounds from natural sources and identify their complex chemical structures using modern NMR tools. For example we isolated few novel limonoids from
Xylocarpus molluccensis,a triterpene from Peganum harmala and bisuracil derivative from marine sea hare (Dolabella auricularia).