Studies on the Constituents of Adelostemma gracillimum.

The glycone portion of the glycoside of ADELOSTEMMA GRACILLIMUM Hook. f. (Asclepiadaceae) was investigated. Three known polyoxypregnane ester-type aglycones, penupogenin ( 1) (1, 2), kidjoranine ( 2) (1, 3), and gagamine ( 3) (4, 5), and one new compound named gracigenin ( 4) were isolated and their structures were characterized on the basis of spectroscopic evidence, and that of ( 4) was determined by X-ray crystallography. It was found to possess an unprecedented 8,14- SECO-polyoxypregnane ester-type skeleton, and 4 is the first compound with this C (21)-steroid type skeleton to be found in nature.

[Study on glycosidal constituents from Epigynum auritum].

A known compound and a new glycoside, epigeoside, were isolated from the rhizomes of Epigynum auritum (Schneid.) Tsiang et P. T. Li (Apocynaceae). The structure of known compound was identified as daucosterol (beta-sitosterol-beta-D-glucopyranoside). The structure of epigeoside has been deduced on the basis of spectral analysis and chemical reactions as catechin-3-O-alpha-L-rhamnopyranosyl-(1----4)-beta-D-glucopyranosyl-(1-- --6) -beta-D-glucopyranoside. Partial hydrolysis of II with 0.2 mol/L HCl afforded compound IIa and rhamnose. Acid hydrolysis of IIa with 2 mol/L HCl afforded an aglycone which was identified by comparison with catechin, and glucose.

New Furans from Cirsium chlorolepis.

From the roots of CIRSIUM CHLOROLEPIS (Compositae) two known compounds, 5-hydroxymethyl-2-furancarboxaldehyde, and 5-methoxymethyl-2-furan-carboxaldehyde, and two new compounds, cirsiumal-dehyde ( 2), and cirsiumoside ( 3), were isolated. Their structures have been elucidated by means of UV, IR, (1)H-NMR, (13)C-NMR spectroscopy, and chemical reactions.

[Studies on the structure of diglycoside from Dregea sinensis var. corrugata].

A new diglycoside, named dregeoside, was isolated from the rhizomes of Dregea sinensis var corrugata (Asclepiadaceae). The structure of dregeoside was deduced on the basis of chemical and spectral evidence as 12, 20-di-O-isovaleryl tomentogenin-3-O-alpha-L-oleandropyranosyl-(1----4)- alpha-L-oleandropyranoside.

[The constituents of C21-steroids from Dregea sinensis var. corrugata].

Drevogenin I, II, two new aglycones, were isolated from Dregea sinensis var. corrugata(Asclepiadaceae). The mass spectrum suggests the presence of two isovaleryl groups. Alkaline hydrolysis of compound I with 5% methanolic potassium hydroxide yielded deacyldrevogenin Ia and isovaleric acid. The acid was esterified with methanol--surfuric acid to afford methyl-isovalerate. By GLC comparison with authentic sample, relative retention time was the same, 1H-NMR shift (delta ppm) and coupling constant were the same, too. On the basis of spectroscopic analysis and chemical reactions, given above the structure of aglycone I was established as C/D cis 5 alpha-H, 3 beta, 8 beta, 14 beta, 17 beta tetrahydroxy-12 beta-O-isovalery1-20-O-isovalerylpregnane. MS molecular weight 552 and elementary analysis were compatible with C31H52O8. The structure of aglycone II was established as C/D cis 5 alpha-H, 3 beta, 14 beta, 17 beta trihydroxy-12 beta-O-acetyl-20-O-benzoyl-pregnane. The mass spectrum suggests the presence of benzoyl and acetylgroups. Alkaline hydrolysis of II with 5% methanolic potassium hydroxide yielded tomentogenin IIa and an acetic acid. Partial alkaline hydrolysis of II with 8% K2CO3--MeOH--H2O absorbed a 12-hydroxy-20-O-benzoyl-pregnane.

Two new antiepilepsy compounds--otophyllosides A and B.

Two new C21 steroidal constituents, named otophylloside A(IV) and otophylloside B(V), have been isolated from the roots of Cynanchum otophyllum Schneid, whose structures have been analysed in this paper by using X-ray crystallography and spectrometric data (UV, IR, 1H- and 13C-NMR, MS) and chemical reaction. They were found to be active against epilepsy, IV and V can protect rats from audiogenic seizures (AS) and its ED50 = 10.20 mg/kg.