Bioassay-directed fractionation of a methanolic extract from the seeds of Draba nemorosa (Brassicaceae) led to isolation of a new flavonol glycoside, drabanemoroside (5, kaempferol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranose) along with four known flavonoid derivatives (1-4), four cardenolide glycosides (6-9). Kaempferol glycosides 2 and 5 showed strong cytotoxicity against human small lung cancer cell line A549 and melanoma SK-Mel-2 with an IC(50) of 0.5 microg/mL and 1.9 microg/mL, respectively. Cardenolide glycosides 6-9 showed potent cytotoxicity (A549) in the range of 0.01-0.032 microg/mL. Their structures were characterized based on spectroscopic data (2D NMR, HRTOFMS, IR, and UV) and comparison of literature values. The carbohydrate units were also confirmed by comparing the hydrolysate of 5 with authentic monosaccharides.

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Kinetics and mechanism of the free-radical polymerization of methyl acrylate (MA), using potassium peroxomonosulfate (PMS) as a water-soluble initiator in the presence of benzyltributylammonium chloride (BTBAC) as a phase-transfer catalyst (PTC), were studied. The polymerization reactions were carried out under inert and unstirred conditions at a constant temperature of 60 AE 1 C in ethyl acetate= water biphasic medium. The rate of polymerization (R p ) increased with an increase in the concentrations of MA, BTBAC and PMS. The order with respect to the monomer, initiator, and PTC was found to be 1.0, 0.5, and 0.5 respectively. R p was independent of the ionic strength and pH of the medium. Based on the kinetic evidences a suitable mechanism is proposed.