ent-kaurane diterpenoids from Isodon japonicus

Abstract

Five ent-kaurane diterpenoids, 6 beta,7 beta, 14 beta-trihydroxy-1 alpha,19-diacetoxy-7 alpha,20-epoxy-ent-kaur-16-en-15-one (1), 1 alpha,6 beta,7 beta-trihydroxy-11 alpha,19-diacetoxy-7 alpha,20-epoxy-ent-kaur-16-en-15-one (2), 6-hydroxy-1 alpha,19-diacetoxy-6,7-seco-ent-kaur-16en-15-one-7,20-olide (3), 19-hydroxy-1 alpha,6-diacetoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide (4), and 6-aldehyde-1 alpha,19-diacetoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide (5), along with 10 known ent-kaurane diterpenoids, pseurata C (6), longikaurin C (7), effusanin C (8), longikaurin B (9), longikaurin D (10), effusanin D (11), excisanin B (12), lasiokaurin (13), megathyrin A (14), and loxothyrin A (15), were isolated from the aerial parts of Isodon japonicus. Their structures were determined on the basis of spectroscopic (1D-, 2D-NMR and MS) and chemical evidence. The isolates were evaluated for their inhibitory effects on LPS-induced production of nitric oxide in murine macrophage RAW264.7 cells.