Two new sesquiterpenes and six norsesquiterpenes from the solid culture of the edible mushroom Flammulina velutipes

One new sesquiterpene with a novel carbon skeleton, flammulinol A (1), one new isolactarane sesquiterpene and six isolactarane-related norsesquiterpenes, flammulinolides A-G (2-8), as well as sterpuric acid, were isolated from the solid culture of Flammulina velutipes. The structures of the new compounds were elucidated by spectroscopic methods. The absolute configuration of C-3 in 1 was determined via the circular dichroism data analysis based on the octane rule of cyclopentenone, whereas the absolute configurations of compounds 2, and 5-8 were assigned using the circular dichroism data of the [Rh-2(OCOCF3)(4)] complex. Compounds 2, 3, and 7 showed strong cytotoxicity against KB cell line with the IC50 of 3.9, 3.6, and 4.7 mu M, respectively. Compound 4 showed strong cytotoxicity against Hela cell line with the IC50 of 3.0 mu M. The plausible biosynthetic pathway for 2-9 in F. velutipes was discussed. (C) 2012 Elsevier Ltd. All rights reserved.