A new anti-hypoxia sesquiterpene from the rhizome of Petasites japonicas.

A new sesquiterpene, bakkenolide-Ⅵa (1), was isolated from the rhizome of Petasites japonicas (Sieb. et Zucc.) Maxim. The structure was characterized on the basis of various NMR ((1)H, (13)C, (1)H-(1)H COSY, HMQC, HMBC and NOESY) and mass spectrometry data. Bakkenolide-Ⅵa showed potent cerebral hypoxia- ischemia protective activity in mice subjected to decapitation through prolonging the survival time and gasping time. It also exhibited a protective activity against hypoxia injury in PC12 cells in anaerobic culture by inhibition of lactate dehydrogenase (LDH) release.