泡果荠属(十字花科)五新种

Haec species proxima H．changhuaensi Y. H．Zhang，a qua racemis longioribtus，laxioribus，siliculis longe obovoideis，stylis longlogioribus sub fructu c． 2 mm longis，seminibus superificie tuberculis minoribus dense munitis recedit．

THE CONSTITUENTS OF C21-STEROIDS FROM DREGEA SINENSIS VAR. CORRUGATA

Drevogenin, a new aglycone was isolated from Dregea sinensis var. corrugata(Asclepiadaceae). On the basis of spcctroscopic analysis and chemi- cal reactions, the structure was established as C/D cis 5α-H、3β、8β、14β、17β8 tetrahydroxy1-12β-O-isovalery1-20-acetyl-pregmame. The molecular formula of C28 H46O8 (M+ at m/z 510) anal. Calcd. for C28 H48O8 (%): C 65.88. H 9.02; Found: C 66.22, H 9.20 The mass spectrum suggests the presence of an isovaleryl and acetyl. Alkali hydrolysis of (I ) with 5% methanolic potassium hydroxide yields dcacyldrevogenin (II) and two acids, i. e. isovaleric and acetic acid. These two acids were estcrified with methanol-surfuric acid to obtain methyl-isovalerate and methyl--acetate. By GLC comparison with authentic specimen relative reten-tion time is the same. In addition, a know compound -β-sitostcrol-β-D-glucoside was isolated from the plant.