Abstract
In an in vitro screening for anti-influenza agents from European polypores, the fruit body extract
of Gloeophyllum odoratum dose-dependently inhibited the cytopathic effect of the H3N2 influenza virus A/Hong
Kong/68 (HK/68) in Madin Darby canine kidney cells with a 50% inhibitory concentration
(IC50) of 15 µg/mL, a noncytotoxic concentration. After a chromatographic work-up, eight
lanostane triterpenes (1–8) were isolated and their structures were elucidated based on high-resolution electrospray
ionization mass spectrometry analyses, and one- and two-dimensional nuclear magnetic
resonance experiments. Constituents 1 (gloeophyllin K) and 2 (gloeophyllin L) are reported here for the first time, and compounds 5, 7, and 8 have not been described for the investigated fungal material so far. The highest
activity was determined for trametenolic acid B (3) against HK/68 and the 2009 pandemic H1N1 strain A/Jena/8178/09 with IC50 values of 14 and 11 µM, respectively. In a plaque reduction assay, this compound
was able to bind to cell-free viruses and to neutralize their infectivity.
Key words
Gloeophyllum odoratum
- Gloeophyllales - polypores - lanostane triterpenes - anti-influenza