Chemical Composition and Antitumor Activities from Givotia madagascariensis

Two new erythroxylane diterpenes, named givotin A (1) and givotin B (2) were isolated from the bark of Givotia madagascariensis. Their structures have been established as 3a,12a-dihydroxy-4(19),15-erythroxyladiene (1) and3a-hydroxy-4(19),15-erythroxyladiene (2), respectively, on the basis of one and two-dimensional NMR spectroscopic studies ( 1 H, 1 3 C, COSY, HMQC, HMBC, NOESY, NOE difference spectra) as well as on mass spectral analysis. In addition six known compounds (3-8) have been isolated and identified. Cleistanthol (3), spruceanol (4) and 1,2-dihydroheudelotinol (5) demonstrated significant antitumor activities against three tumor cell lines (HM02, Hep G2, MCF7).