Two new ent-atisane diterpenes from Sapium sebiferum.

Two new ent-atisane diterpenes, sebiferumnins K and L (1 and 2), were isolated from the branches of Sapium sebiferum, together with four known compounds, ent-3-oxoatis-16α, 17-acetonide (3), ent-l6α, 17-dihydroxyatisan-3-one (4), ent-atisane-3ß, 16α, 17-triol (5), ent-3α-hydroxyatis-16α,17-acetonide (6). The structures of these two ent-atisane diterpenes were elucidated by extensive analyses of the spectroscopic data. [Formula: see text].

Antibacterial and antioxidant properties of crude extract, fractions and compounds from the stem bark of Polyscias fulva Hiern (Araliaceae).

BACKGROUND: In our previous work, the dichloromethane-methanol (1:1 v/v) extract, fractions and isolated compounds from Polyscias fulva stem bark showed interesting antifungal activity. As a continuity of that work, this study aimed to bring out complementary informations about the antimicrobial properties of P. fulva stem bark that may be useful in the standardization of phytomedicine from this plant. METHODS: The antibacterial activities of the crude extract, fractions (n-hexane, ethyl acetate, n-butanol and residual) and isolated compounds from Polyscias fulva stem bark were assayed by broth microdilution techniques. Their antioxidant activity were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), pyrogallol (superoxide anion) and ß-carotene - linoleic acid assays. RESULTS: The crude extract presented antibacterial activities against S. typhi (ATCC 6539), E. aerogenes (ATCC 13045), P. aeruginosa (PA01) and E. coli (ATCC 10536) with MIC values of 2000 to 8000 µg/ml. The fractionation led the ethyle acetate and n-butanol fractions relatively more active (MIC = 500 to 1000 µg/ml) as compared to the crude extract. ß-sitosterol and 3-O-α-L- arabinopyranosyl-hederagenin were the most active compounds on the tested bacteria with MIC values ranging from 6.25 to 100 µg/ml. The most sensitive was P. aeruginosa (PA01) on which all the tested compounds were active with MICs ranging from 6.25 to 400 µg/ml. Among all the tested substances, the crude extract (RSa50 = 84.86 µg/ml) and the methyl atrarate (RSa50 = 14.77 µg/ml), showed the highest scavenging activities against DPPH free radicals and those arising from the oxidation of the linoleic acid respectively. CONCLUSION: From this study, the results obtained reveal that the stem bark of P. fulva possesses antibacterial and antioxidant activities. It may then be useful in the development of an antimicrobial phytomedicine with a large spectrum of actvity endowed with antioxidant properties which can be standardised based on the isolated compounds.

New antimicrobial pregnane glycosides from the stem of Ecdysanthera rosea.

Phytochemical investigation on the stem of Ecdysanthera rosea led to the isolation of eight new C-21 pregnane glycoside ecdysosides A-H (1-8), together with one known pregnane glycoside ecdysantheroside A (9). Their structures were elucidated based on extensive spectroscopic data (MS, IR, 1D and 2D NMR) analysis, as well as comparison with the reported literature data. Antimicrobial activities of all the compounds were evaluated against bacteria and yeasts. Compounds 1, 9, 3 and 5 exhibited moderate antibacterial activities against respective Enterococcus faecalis and Providensia smartii, with MIC value of 12.5 µg/mL. Compound 8 showed significant anti-yeast activity against Cryptococcus neoformans with MIC value of 12.5 µg/mL.