Bioactive metabolites from the mycelia of the basidiomycete Hericium erinaceum

Seven known compounds, three diketopiperazine alkaloids, 12 beta-hydroxyverruculogen TR-2 (1), fumitremorgin C (2) and methylthiogliotoxin (5), two hetero-spirocyclic gamma-lactam alkaloids, pseurotin A (3) and FD-838 (4), and cerevisterol (6) and herierin IV (7), were isolated from the mycelia of the basidiomycete Hericium erinaceum and identified by spectroscopic analyses. The antioxidant and antifungal activities of compounds 1-6 were evaluated. The results indicated that compounds 1, 3 and 6 exhibited potential antioxidant activity against DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical with their IC50 data of ca. 12 mu M, compared with positive control tertiary butylhydroquinone. In addition, compound 4 significantly inhibited the growth of two plant fungal pathogens Botrytis cinerea and Glomerella cingulata with an minimum inhibitory concentration of 6.25 mu M for each, similar to that of the positive fungicide, carbendazim. Compounds 1-5 were isolated from the genus Hericium for the first time.