Yatendra Kumar’s research while affiliated with I.T.S. Pharmacy College and other places

The present investigation is to evaluate the antioxidant activity of various extracts of root and leaf of F. strobilifera using different in vitro methods and its phytochemical analysis. The antioxidant activity was studied by DPPH radical scavenging method, nitric oxide radical inhibition assay and scavenging of hydroxyl radical by p-NDA method. Methanolic extract of root and leaf of F. strobilifera showed a very good DPPH radical scavenging activity with low IC50 values of 11.4 μg/ml and 38.0 μg/ml respectively. Butanolic extract of F. strobilifera root showed good nitric oxide radical inhibition activity with IC50 of 150.0 μg/ml in a dose-dependent manner. The methanolic extract of root showed hydroxyl radical scavenging by p-NDA method with IC50 value of 378.33 μg/ml. Subsequent quantification showed the presence of 13.75 and 8.84 % w/w phenolics (calculated as gallic acid), 2.14 and 3.26 % w/w of flavonol in methanol extract of root and leaf of F. strobilifera respectively. The high amount of flavonols and phenolics prompted us to evaluate its antioxidant activity. This study revealed that methanolic extract of F. strobilifera comprise effective potential source of natural antioxidant, which might be helpful in preventing the progress of various oxidative stresses.

The Sweet Herb of Paraguay, Stevia rebaudiana (Bert.) Bertoni is fast becoming a major source of high potency sweetener which produces sweet taste but has no calorific value. Many research activities on its chemical and biological properties have been done in recent past. Several countries including India have started its commercial cultivation. The published literature on this crop is quite scattered. Therefore an effort to compile the literature and review the current status of research and development including cultivation practices has been done in this paper.

A new isoflavone (1) isolated from the roots of Flemingia strobilifera (L) R. Br. was identified as 5,7,4'-trihydroxy 8,2',5'-tri(3-methylbut-2-enyl)isoflavone along with the known phytoconstituents: 5,7,2',4'-tetrahydroxyisoflavone (2), 5,7,4'-trihydroxyisoflavone (3) and beta-sitosterol (4). Structure assignments were performed on the basis of spectroscopic data including homo- and heteronuclear 1D and 2D NMR (COSY, HMBC and DEPT) and MS studies. The compounds were tested in vitro for antimicrobial activity and antioxidant activity and compounds (1-3) proved to be moderately active.

A new phenolic glucoside, (rel)-2-(4',6' -dibenzoyl-beta-glucopyranosyloxy)-7-(1alpha-hydroxy-2alpha-ethoxy-6alpha-acetyloxy-3-oxocyclohex-4-enoyl)-benzyl alcohol (Flacourticin) (1) and the known, 2-(4',6'-dibenzoyl-beta-glucopyranosyl)-5-hydroxy benzyl alcohol (4'-benzoylpoliothrysoside) (2) together with the new, (2E)-heptyl-3-(3,4-dihydroxyphenyl) acrylate (3), (+)-catechin (4) and sitosterol-beta-D-glucoside were isolated from Flacourtia indica. Their structures were assigned on the basis of 1D, 2D-NMR and as well by analysis of the LC-ESIMS data. The isolated compounds (1-4) were evaluated for alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical scavenging activity, and 3 was found to be two-fold less potent, with an IC50 = 12.01 microg/mL, compared to the positive control, Rutin, (IC50 = 5.83 microg/mL).

Purpose: To carry out a bioactivity guided fractionation and isolation of the antimicrobial constituent(s) of the roots of Flemingia strobilifera against some bacteria and fungi. Methods: The root of F. strobilifera was extracted with methanol, butanol and dichloromethane. Antimicrobial activity of the extracts was determined against both bacteria and fungi while the isolation and characterization of compounds of the extracts was done by column chromatography,2D spectroscopic studies and spectral data (U.V, I.R, NMR and MS). Results: Flemingia flavanone (8, 3'-diprenyl-5, 7, 4'-trihydroxy flavanone), Genistin (5, 4 'dihydroxy isoflavone 7-O-glucoside) and β - sitosterol-D glucoside were isolated from the extracts. Flemingia flavanone showed significant antimicrobial activity against Gram-positive (S. aureus, S. epidermidis, MRSA), Gram-negative bacteria (Ps. aeruginosa, E. coli) and fungi (C. albicans). Genistin showed moderate activity against Gram-positive, Gram-negative bacteria and fungi. Conclusions: The isolation and antimicrobial activity of presence of Flemingia flavanone is being reported for the first time.

A simple and sensitive spectrophotometric method has been developed for the quantitative estimation of Rosuvastatin Calcium (RC) in bulk and its tablets. RC shows maximum absorbance at about 242 nm and obeys Beer's law in the concentration range of 4 to 24 g/ml. The method is found to be simple, precise and accurate and can be applied for the routine estimination of Rosuvastatin Calcium in dosage form.