A new fungicidal lactone from Xylocarpus granatum (Meliaceae).

A new lactone was isolated from the leaves of Xylocarpus granatum, along with three known compounds: triacontanol, beta-sitosterol and kaempferol-3-O-beta-D-glucoside. Its structure was elucidated as 3-(1-hydroxyethyl)-4,4-dimethyl-4-butyrolactone (1) by infrared, (1)H and (13)C NMR and ESI-MS data. At a concentration of 20 microg mL(-1), the new lactone gave a 67.4% inhibition rate against wheat powdery mildew.