Brine Shrimp Lethality Test Active Constituents and New Highly Oxygenated Seco-prezizaane-Type Sesquiterpenes from Illicium merrillianum

Abstract

In the study of bioactive substances in Illicium plants, the methanol extract of I. merrillianum showed brine shrimp lethality test (BST) activity at 200 µg/ml. Bioassay-guided fractionation of the BST active fractions resulted in the isolation of 4-O-methyleudesm-11-en-4α-ol, eudesmol-11-en-4α-ol and (−)-hinokinin as potent BST active compounds. On the other hand, four new highly oxygenated seco-prezizaane-type sesquiterpenes, merrilliortholactone (1), 2α-hydroxycycloparvifloralone (2), 2α-hydroxycycloparviflorolide (3), and 2α-hydroxyanisatin (4) were isolated from the BST-inactive polar fractions. The structures of new compounds were elucidated by extensive analyses of spectral data. Furthermore, the absolute configuration of 3 was established by the modified Mosher's method. Compounds 1—4 showed neither BST activity at 100 µg/ml nor neurite outgrowth-promoting activity.