Lentinoids A-D, New Natural Products Isolated from Lentinus strigellus.

Four novel lentinoids (1-4), along with the known compounds striguellone A (5), isopanepoxydone (6) and panepoxydone (7), were isolated as part of our studies on Lentinus strigellus. The structures of 1-4 have been established by 1D- and 2D-NMR and MS analysis. Compounds (1-3) and (5-7) were tested against Listeria monocytogenes, Enterococcus faecalis, Pseudomonas aeruginosa and Klebsiella pneumoniae. These compounds showed inhibition diameters ranging from 7.5-9.5 mm, however, when the minimum inhibitory concentration (MIC) was determined, only compound 1 showed a significant activity of 200 μg/mL. Intermediates for the biosynthesis of the oxygenated cyclohexenyl derivatives isolated from lentinoid fungi (genera Lentinus and Panus) are proposed.