New antifungal pyranoisoflavone from Ficus tikoua Bur.

Considering the undesirable attributes of synthetic fungicides and the availability of Ficus species in China, the stem of Ficus tikoua Bur. was investigated. One new antifungal pyranoisoflavone, 5,3',4'-trihydroxy-2″,2″-dimethylpyrano (5″,6″:7,8) isoflavone (1), together with two known isoflavones, wighteone (2) and lupiwighteone (3) (with previously reported antifungal activities), were isolated from ethyl acetate extract by bioassay-guided fractionation. Their structures were determined by spectroscopic analysis, such as NMR ((1)H-(1)H COSY, HMQC, HMBC and NOESY), IR, UV and HRMS, as well as ESI-MS(n) analyses. The antifungal activities of 1-3 against Phytophthora infestans were evaluated by direct spore germination assay, and the IC(50) values were 262.442, 198.153 and 90.365 μg·mL(-1), respectively.