Antifungal, antioxidant and larvicidal activities of compounds isolated from the heartwood of Mansonia gagei

Eleven compounds isolated from the heartwood of Mansonia gagei were tested for their antifungal activities against Cladosporium cucumerinum and Candida albicans, as well as for their larvicidal activities against Aedes aegypti and radical scavenging properties in a DPPH assay. Mansonone C (4) was found to be the most interesting compound with antifungal activities against Cladosporium cucumerinum and Candida albicans as well as for its larvicidal properties against Aedes aegypti. Mansonone E (5) was active against Cladosporium cucumerinum and Candida albicans. Two coumarin derivatives, mansorin A (1) and mansorin B (2) were also found to be active against Cladosporium cucumerinum, while mansonone N (9) was the only isolated product to show radical scavenging properties. Copyright (C) 2003 John Wiley Sons, Ltd

Four new sesquiterpenoid derivatives from the heartwood of Mansonia gage.

Four new sesquiterpenoid derivatives named mansonones N (1), O (2), P (3), and Q (4) were isolated from a dichloromethane extract of the heartwood of Mansonia gagei, a plant used in folk medicine in Thailand. Their structures were resolved on the basis of spectrometric data interpretation and the single-crystal X-ray analysis of 1 and 2

Cyclic tetrapeptides from marine bacteria associated with the seaweed Diginea sp.and the sponge Halisarca ectofibrosa

A Pseudomonas sp. was cultured which was associated with the Japanese seaweed Diginea sp. Crude extracts prepared from this bacterial culture were found to inhibit the growth of other marine bacterial strains. From this bacterial culture, two new peptides cyclo-[phenylalanyl-prolyl-leucyl-prolyl] (3) and cyclo-[isoleucyl-prolyl-leucyl-alanyl] (4) have been isolated together with two known peptides (1) and (2). The crude extract from a culture of Pseudoalteromonas sp. associated with the Thai sponge Halisarca ectofibrosa was found to inhibit the growth of Bacillus subtilis and Vibrio anguillarum. Isolation studies yielded a fraction containing two peptides that were identified as cyclo-[phenylalanyl-leucyl] (5) and cyclo-[leucyl-isoleucyl] (6) by means of LC-MS and 2D NMR data. Absolute stereochemistry was confirmed by the synthesis of cyclo-[l-phenylalanyl-l-leucyl]. Peptides (1)-(3) were also isolated from this bacterial strain. None of the individual peptides isolated in this study showed antibiotic activity