PUB - Publikationen an der Universität Bielefeld

Two new 24-nor-ursane-type triterpenoids, 2 alpha, 3 beta, 19 alpha-trihydroxy-24-norurs-4(23), 12-dien-28-oic acid (1) and 3 beta-acetoxy-2 alpha, 19 alpha-dihydroxy-24-norurs-4(23), 12-dien-28-oic acid (2), along with 15 known compounds were isolated from the methanol extract of the twigs of Mostuea hirsuta. While 2-hydroxymethylbenzamide (13) was isolated for the first time from the natural source, compounds 3-12 are reported here for the first time from the genus Mostuea. Their structures were elucidated by means of spectroscopic analyses including 1D- and 2D-NMR spectroscopy, high-resolution mass spectrometric data as well as comparison with data from the literature. Compounds 1, 2, 4-9 and 13 were tested against bacteria, fungi and plant pathogen oomycetes by the paper disk agar diffusion assay resulting in missing to low activities corresponding with minimum inhibitory concentrations (MICs) > 1 mg mL(-1). However, the respective compounds 1, 2, 8, 9 and 13 exhibited moderate cytotoxic activity against the human Caucasian prostate adenocarcinoma cell line PC-3, with IC50 10.6-16.5 mu m compared to the standard doxorubicin with IC50 0.9 mu m.