A new meroterpenoid asperdemin (1) and two known compounds, viz., diorcinol (2) and viridicatol (3), were isolated from the marine fungus Aspergillus versicolor. The structures of these compounds were established by NMR spectroscopy and high resolution mass spectrome try. The absolute stereochemistry of 1 was determined by modified Mosher's method. The antimicrobial activity of the total extract from A. versicolor was attributed to diorcinol (2). Asperdemin exhibits weak cytostatic and membranolytic activities in developing embryos of the sea urchin Strongylocentrotus nudus.

Ten secondary metabolites including flavonoids (1-8), caffeic (9) and chlorogenic (10) acids were structurally identified from the extract of Sakhalin bilberry Vaccinium smallii leaves and studied in vitro as potential cancer-preventive agents. The results showed that compounds 1-10 inhibited EGF-induced neoplastic transformation of mouse JB6 Cl 41 P+ cells in soft agar with an inhibition concentration (INCC50) of 20-80 µm. Moreover, all these natural products were non-toxic against JB6 Cl 41 P+ cells up to a concentration of 200 µm.

No abstract

No abstract

19-Norspongia-13(16),14-diene-3-one (1) was isolated for the first time from a natural source, along with a series of known spongiane diterpenoids (2-11) and sesquiterpene (12) from two unidentified species belonging to the genus Spongia. The effects of 1, 4, 5, 8-12 on biosynthesis of nucleic acids and embryonic development of the sea urchin Strongylocentrotus intermedius have been studied. All the compounds inhibit sea urchin embryo development at concentration of 20  g/mL and above and DNA biosynthesis at the dose of 10  g/mL. The inhibitory effect of diterpenoids at least partly may be explained by the inhibition of thymidine kinase activity.