Isolation and biological evaluation of demethylcassiarin B from Senna siamea Lam.

In search of potential natural products for the amelioration of obesity, phytochemical investigation of leaves of Senna siamea Lam. was carried out. It led to the isolation of demethycassiarin B (1), 6,8-dihydroxy-3-methyl-1H isochromenone (2), and 6-hydroxymellein (3). The structures were elucidated by a detailed analysis of spectral data. Compound 1 was found to possess a similar structural skeleton as that of cassiarin B except for a methoxyl substitution. Detailed HPLC and HPTLC analysis of methanolic extract for the presence of compound 1 and cassiarin B were performed. Cassiarin B was not detected in extract. Compounds 2 and 3 have been reported for the first time from the genus Senna. The isolated compounds were evaluated for their antiadipogenic activity in murine 3T3L1 cells.

Isointricatinol, a new antioxidant homoisoflavonoid from the roots of Caesalpinia digyna Rottler.

A new homoisoflavonoid, isointricatinol (1), together with eight known homoisoflavonoids, three flavonoids, bergenin and 11-O-galloylbergenin were isolated from the EtOAc fraction of MeOH extract of Caesalpinia digyna roots and evaluated for the antioxidant activity against DPPH and ABTS free radicals. The structure of 1 was elucidated by various spectroscopic techniques and found to be a Z-isomer of 7,8-dihydroxy-3-(4'-methoxybenzyl)chroman-4-one. Compound 1 was found to exhibit mild to moderate free radical scavenging effect against DPPH (IC(50), 85.50 µM) and ABTS (IC(50), 44.13 µM) radicals.

Simultaneous determination of hydrazinocurcumin and phenol red in samples from rat intestinal permeability studies: HPLC method development and validation.

Hydrazinocurcumin (HZC) is a patented multiactivity compound and is a potent derivative of curcumin which is not yet explored for further development as formulation and requires the determination of biopharmaceutical suitability of the molecule. Intestinal permeability and logP of a compound are two vital biopharmaceutical properties by which, any "hit" molecule proceeds towards NCE (new chemical entity) and govern formulation design of bioactive molecules. In this report, a simple, precise and accurate isocratic reverse phase (RP) liquid chromatography method for simultaneous analysis of HZC and phenol red, for the application in rat in situ single-pass intestinal perfusion (SPIP) was developed and validated using FDA bioanalytical guidelines. RP-HPLC method was developed on C-18 column with UV detection at 332 nm for both the compounds. Isocratic run with the mobile phase consisting of organic phase (methanol:acetonitrile:: 50:20 v/v) and water in the ratio of 80:20 v/v provided a short run time of 7 min with resolution of more then two without interference of blank matrix. The working/expected concentration range for HZC and phenol red were 0.5-50 and 2-200 microg/ml. LOQs for HZC and phenol red of the method was found to be 0.167 and 0.271 microg/ml respectively. The validation parameters indicate that method was suitable for the intended purpose. Permeability, considering water flux with the help of non-permeable marker phenol red was calculated to be 0.34 x 10(-4)cm/s. Along with other descriptors, logP (1.78) and MW (<500) of HZC makes it a potential candidate for oral formulation.

Electronic effects in migratory groups. [1,4]-versus[1,2]-rearrangement in rhodium carbenoid generated bicyclic oxonium ylides.

The variety of alpha-diazo beta-keto esters (3a-f, 8a-f) with varying substituents (ED/EW) on the phenyl ring of the O-benzyl group were prepared. The rhodium(II) acetate catalyzed decomposition of diazo compounds in benzene reflux conditions. The ratio of 1,4 versus 1,2 migration product was determined. It was found that an increase in electron density on the benzylic carbon of the migrating group prefers 1,4 migration products (4, 9) while a decrease in electron density leads to a preponderance of 1,2 migration products (5, 10). The results obtained were correlated to the mechanistic aspect of the product selectivity. The intermediacy of the intramolecular oxonium ylide formation was demonstrated by crossover experiments. The preference for the formation of 2,3 sigmatropic rearrangement product over 1,2 and 1,4 was demonstrated by performing the reaction with alpha-diazo beta-keto esters (13a, 13b) with O-allyl and O-propargyl at C3. The effect of solvent, temperature, and mole percentage of rhodium(II) acetate was also studied.

Antiinflammatory activity of extracts of Biophytum sensitivum in carrageenin-induced rat paw oedema.

The antiinflammatory activity of aqueous and methanol extracts of aerial parts, an aqueous extract of roots as well as ultrafiltration fractions of a methanol extract of roots of Biophytum sensitivum were evaluated in the carrageenin induced rat paw oedema model. All the extracts except the methanol extract of aerial parts exhibited antiinflammatory activity, but inhibition of oedema was found to be maximum with aqueous extracts.

Amentoflavone from Biophytum sensitivum and its effect on COX-1/COX-2 catalysed prostaglandin biosynthesis.

Amentoflavone (I3', II8-biapigenin) was isolated from the roots of Biophytum sensitivum DC. (Oxalidaceae) and proved to be a selective inhibitor of cyclooxygenase (COX)-1 catalysed prostaglandin biosynthesis when tested in vitro with an IC (50) value of 12.4 microM (standard: indomethacin, IC (50) = 1.1 microM). Doses of up to 37 microM showed only a slight inhibition in the corresponding COX-2 assay. Quantification of amentoflavone was carried out by reversed phase HPLC in methanolic and aqueous extracts of the roots, stems and leaves. Highest amounts of amentoflavone were detected in methanolic extracts of roots and stems (0.26-0.35%), while considerably lower amounts were detected in the corresponding water extracts.