Antifungal activity against Colletotrichum acutatum and Colletotrichum gloeosporioides of the major constituents from wood sawdust of Platymiscium gracile Benth

The tree tomato (Solanum betaceum Cay., Solanaceae) anthracnose, caused by the fungi Colletotrichum acutatum and Colletotrichum gloeosporioides, is the most important disease of this crop in Colombia for its wide distribution and the losses it causes. In the present work, the in vitro antifungal activity of the soluble fractions in n-hexane, dichloromethane, and ethyl acetate, and their major constituents from the sawdust of timber specie Platymiscium gracile Benth. (Fabaceae) against both fungi was evaluated. The n-hexane soluble fraction exhibited the greatest inhibitory effect. The metabolites homopterocarpin (a pterocarpan, 0.39% dry weight), calycosin (an isoflavone, 2.01%) and scoparone (a coumarin, 1.48%) were isolated for the first time from wood sawdust of P. gracile. The structure of these compounds was determined by H-1 and C-13 NMR analyses. The three compounds tested showed significant antifungal activity.