This Ph.D thesis comprises of three parts. Part A deals with the phytochemical studies of Withania somnifera (L. Dunal), part B describes the phytochemical investigation on physalis minima Linn., while part C focuses on the biotransformation of physalin H, a bioactive plant metabolite.
Part A the phytochemical studies on the chloroform extract of withania somnifera (L. Dunal), have afforded two new and three known withanolides. The cholinesterase inhibiting activity of these compounds was evaluated by one of our colleagues, Dr. Sarfraz Ahmad Nawaz, in the enzyme inhibition laboratory of the H.E. J. Research institute of Chemistry, and all compounds were found to possess varying degree of cholinesterase inhibitory potential in a concentration â€“ dependent manner.
New withanolides isolated from withania somnifera
Chem, pharm. Bull., 52 (11), 1358 (2004).
Known withanolides Isolated from withania somnifera
Part B of the thesis contains details of the isolation of six new and three known antieishmanial physalins from the chloroform extracts of physalins minima Linn. (var. indica). The antileishmanial activity of these compounds were evaluated by Ms. Samreen in the Bioassay section of the H.E. J. Research Institute.
New Compound Isolated from Physalis minima
Chemistry and Biodiversity, 2, 1164 (2005).
Natural Product Research, 2006 (Accepted).
Known Compounds Isolated from Physalis minima
All compounds were founds to possess significant antileishmanial activities with the IC50 values between 0.92 to 38.9 ug / ml, by using amphotericin as the standered drug (IC50=0.12 ug / ml ).
Part C focuses on the biotransformation of physalin H (isolated during the phytochemical investigation on physalis minima) by inculbation with Rhizopus stolonifer and cunninghamella elegans, results in two new (95 and 96) and one known metabolite 84. These metabolites were screened for their antileishmanial activities.
Chem. Pharm. Bull., 52 (11), 1358 (2006).
The structures of compounds, isolated from the withania somnifera and physalis minima together with transformed metabolites, were elucidated through spectroscopic methods such as UV, IR, 1H â€“ and 13C-NMR and 2D-NMR techniques (COSY, NOESY, NOE, HMBC, HMQC).