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A continuous phytochemical study on the roots of Marsdenia tenacissima led to the isolation and identification of 13 new polyoxypregnane glycosides named marstenacissides B10-B17 (1, 2,4,7,8,11,12, and 14) and marstenacissides A8-A12 (3, 9,10,13, and 15) in addition to two known polyoxypregnane glycosides marsdenosides M and L (5 and 6). Their structures were established by spectroscopic techniques and by comparison with the reported data in the literature. Moreover, the anti-HIV activities of these isolates and the previous isolated marstenacissides A1-A7 and B1-B9 were assessed, some of which exhibited slight or negligible effects against HIV-1. [ABSTRACT FROM AUTHOR]

The present paper is devoted to preparation and characterization of catalyst for oxygen reduction reactrion (ORR) based on pyrolyzed metal-poly(ethyleneimine)(namely M-PEI, M=Co, Fe, Ce). Template method was applied to obtain catalyst with high surface area and porosity. Results of electrochemical characterization, which was performed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) employing a rotating disk electrode (RDE), with emphasis on the activity of the catalyst are presented. The catalytic activity was found to depend strongly on the kind of transition metal and anion species. The relation of eletrocatalytic activity varies as follows: Co > Fe > Ce for transition metals and, nitrate > sulfate for anion species. Co-PEI, with onset potential at 0.1V, half-wave potential at 0V and average transferred electron number at 3.3, was found to show the highest ORR activity among the catalysts studied.