Abstract
Labdane-type diterpenes 1 a, 2 a and 3 a were previously isolated from Metasequoia glyptostro-boides in our laboratory. These compounds were found to inhibit the spore germination of Pyricularia oryzae. The antifungal properties of 1 a, 2 a and 3 a, and their nine derivatives were examined to investigate the relationship between structure and antifungal activity.
The results suggested that the carboxyl group at the side chain and hydroxyl group at C-3 position were related to strong antifungal activity, and that the conjugated double bond and exomethylene group had little effect on the activity.
