13 These observations have spurred aggressive efforts to synthesize14 as well as isolate and identify α-glucosidase inhibitors from traditional medicinal plants15 for development of new therapeutics. Postprandial
hyperglycemia is also reported to induce oxidative stress by overt generation of free radicals16 XAV-939 datasheet that further aggravate diabetic complications17 Therefore, combination of α-glucosidase inhibitory and free radical scavenging properties in a therapy appears to become an exciting therapeutic strategy for the management of postprandial hyperglycemia as well as attenuation of resultant oxidative stress. In the course of our study on traditional medicinal plants, we have reported several phytochemicals possessing
these activities.18 In the course of our search for the modulators of dietary carbohydrates digestion for the management of postprandial hyperglycemia in diabetes, we encountered potent α-glucosidase inhibitory and free radical scavenging active compounds in P. tomentosa, which find wide usage in Indian medical system, Ayurveda. Herein, we are reporting the isolation and structural elucidation of phytochemicals as a potential α-glucosidase inhibition and free radical scavengers. ABT-199 chemical structure The whole plant material P. tomentosa were collected from the forest of Tirumala in Chitoor Dist. (Andhra Pradesh, India) in the month of January, 2005 and identification was made by Prof. Dr. K. Madhava Chetty, Department of Botany, Sri Venkateshwara University, Tirupathi. Voucher specimens (PT-01–05) of the plants are deposited at the herbarium of the S. V. University. Column chromatography was performed on silica gel (60–120 mesh). Melting points were recorded on Fisher Johns apparatus and were uncorrected. FABMS was
recorded on VG Auto spec-M instrument. IR spectra were recorded on Nicolet spectrometer. 1H NMR and 13C NMR spectra obtained on varian 200, 400 MHz and Bruker 300 MHz spectrometers using TMS as internal standard. HMBC, HSQC, NOSEY and DQCOSY experiments were done on Oxford 500 MHz spectrometer. The dried plant material (2 kg) was powdered and extracted with n-hexanes crotamiton in a Soxhlet apparatus for 24 h. The solvent was evaporated under reduced pressure in a rotary evaporator to obtain a residue (15 g). The residue was adsorbed on silica gel and subjected to column chromatography over silica gel and eluted with n-hexanes first followed by mixture containing increasing amounts of ethyl acetate. The fraction eluted at 2, 4, 6 & 10% were collected separately concentrated and rechromatographed using silica gel (60–120 mesh, 100 g) to obtain compound 6 & 7 (0.012 g & 0.02 g), compound 1 & 2 (0.026 g & 0.03) in pure form. After completing petroleum ether extract, powdered plant material was extracted with chloroform to obtain 20 g of residue.