Tetranorditerpene lactones, potent antifungal antibiotics for human pathogenic yeasts, from a unique species of Oidiodendron.

The culture filtrate of a fungus isolated from decaying Picea glauca wood and tentatively identified as Oidiodendron cf. truncatum showed strong antibiotic activity against the pathogenic yeast, Candida albicans. Four new tetranorditerpenoids, oidiodendrolides A (3), B (4), and C (5) and oidiodendronic acid (7) were isolated along with three known tetranorditerpenoids, LL-Z1271 alpha (= PR1387) (1), PR1388 (2), and acrostalidic acid (6), from rice fermented by the above fungus. The structures of oidiodendrolides A (3), B (4), and C (5) and oidiodendronic acid (7) were established on the basis of spectroscopic and chemical investigations. The antifungal activity of the above tetranorditerpenoids against the pathogenic yeasts, Candida albicans and Cryptococcus neoformans is discussed.