从白背叶[Mallotus aplta(Lour.)Muell.-Arg.]的根得到5个化合物,经化学和波谱分析鉴定结晶 A 为 erythordiol-3-acetate,结晶 B 为β-sitosterol,结晶 D 为3β,29-di-hydro-xylupane,结晶 E 为 ursolic acid acetate 及结晶 F(待鉴定)。以上鉴定的4个成分均系首次从白背叶根中分得的已知化合物。抑菌试验表明结晶 A,B,D,E 和 F 对金黄色葡萄球菌,枯草杆菌、大肠杆菌、绿脓杆菌均有不同程度的抑制作用。 Five compounds were obtained from the root of white back leaf [Mallotus aplta (Lour.) Muell.-Arg.]. Chemical and spectral analyses identified that crystal A was erythordiol-3-acetate, crystal B was β-sitosterol, and crystal D was 3β. 29-di-hydro-xylupane, crystalline E is ursolic acid acetate and crystalline F (to be identified). The four components identified above were all known compounds that were first isolated from the roots of white back lobes. Antibacterial tests showed that crystals A, B, D, E, and F all had different degrees of inhibition on Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa.