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Seven new isoflavones, named euchrenones b 10 –b 16 were isolated from the roots of Euchresta japonica . By means of spectral data, the inuctures were determined to be 5,5′-dihydroxy-2′-methoxy-8-γ,γ-dimethylallyl-[6″,6″-dimethylpyrano(2″,3″:7,6)]-[6″“,6″”-dimethylpyrano(2″“,3″”:4′,3′)]-, 5,5′-dihydroxy-2′methoxy-6-γ,γ-dimethylallyl[6″,6″-dimethylpyrano(2″,3″:7,8)]-[6″“,6″”-dimethylpyrano-(2″“,3″”:4′,3′)]-, 5,4′-dihydroxy-′-methoxy-8,3′-di(γ,γ-dimethylallyl)-[6″,6″-dimethylpyrano(2″,3″:7,6)]-, 5,4′-dihydroxy-2′-methoxy-6,3′-di(γ,γ-dimethylallyl)-6″,6″-dimethylpyrano(2″,3″:7,8)]-, 5,7,4′-trihydroxy-2′-methoxy-6,8,3-tri-(γ,γ-dimethylallyl)-, 5,7,4′-trihydroxy-2′-methoxy-6,8-di(γ,γ-dimethylallyl)- and 5,2′,4′-trihydroxy-6,3′-di(γ,γ-dimethylallyl)-[6″,6″-dimethylpyrano(2″,3″:7,8)]isoflavone, respectively.

In addition to eight known compounds [euchrenones a 6 , a 11 and a 12 , glabrol, euchretins AC, and lespedezaflavanone C], three new coumaronochromones were isolated from the roots of Euchresta japonica . By means of spectroscopic analysis, the structures of new compounds were characterized as 5,7,4′,5′-tetrahydroxy-6,8-di(γ,γ-dimethylallyl)-, 5,4′,5′-trihydroxy-6-γ,γ-dimethylallyl-[6″,6″-dimethylpyrano(2″,3″:7,8)]-, and 5,7,5′-trihydroxy-8-γ,γ-dimethylallyl-[6″′,6″′-dimethylpyrano(2″′3,3″′:4′,3′)]-coumaronochromone, and were named euchretins F, G and H, respectively.

Two new prenylflavanones, named euchrestaflavanone B and C were isolated from the roots of Euchresta japonica . Their structures have been confirmed

Three new prenylflavanones, euchrenone a 1 – a 3 , were isolated from the roots of Euchresta japonica . Their structures were established by s

Nine known lupin alkaloids, (+)-matrine, (+)-matrine N-oxide, (+)-sophoranol, (+)-sophoranol N-oxide, (-)-sophoridine (1), (-)-cytisine, (-)-N-methylcytisine, (-)-N-formylcytisine, (-)-baptifoline, and (-)-sophoridine N-oxide (2a), were isolated from the aerial parts of Euchresta japonica BENTH., in addition to two alkaloids, (+)-5, 17-dehydromatrine N-oxide and (-)-12-cytisineacetic acid, reported previously. 2a was one of the two diastereoisomeric sophoridine N-oxides with different configurations of N-oxide nitrogen. Seasonal variations of the alkaloid contents in the aerial and ground parts of E. japonica were also examined. The N-oxidation of sophoridine with m-chloroperbenzoic acid gave two N-oxides in a ratio of ca. 1 : 5. The minor N-oxide was identical with 2a. The major N-oxide (2b) was characterized as the other diastereomer of sophoridine N-oxide by MS spectroscopy and deoxygenation to sophoridine. The stereochemical assignments of the two isomers were carried out by analysis of their 1H- and 13C-NMR spectra.

Three new prenylisoflavones, designated euchrenones b 1 , b 2 and b 3 , were isolated from the roots of Euchresta japonica . The structures were established on the basis of spectroscopic methods and chemical evidence.

A new lupin alkaloid, (+)-5,17-dehydromatrine N -oxide, was isolated from the fresh aerial parts of Euchresta japonica . Its structure was confirmed by spectrometric data and by direct comparison with a synthetic sample, prepared from (+)-sophoranol ((+)-5-hydroxymatrine). It was also concluded that (+)-5,17-dehydromatrine N -oxide and (+)-matrine N -oxide possess the same configuration with respect to the asymmetric nitrogen by NMR spectra.

A new lupin alkaloid, methyl 12-cytisineacetate 1, was isolated from the MeOH extract of Euchresta japonica . Its structure was confirmed by spectrometric data and by direct comparison with a synthetic sample. However, 1 is an artifact product and 12-cytisineacetic acid (2) is assumed to be the principal source of 1.

Three new flavonoids isolated from the roots of Euchresta japonica, designated as euchrenones a4, b4 and b5, were identified as 5, 7-dihydroxy-6, 8-di(γ, γ-dimethylallyl)-[6'''', 6''''-dimethylpyrano(2'''', 3'''' : 4', 3')]flavanone, 5, 7-dihydroxy-2'-methyoxy-4', 5'-methylenedioxy-6, 8-di(γ, γ-dimethylallyl)isoflavone and 5, 7, 2'-trihydroxy-4', 5'-methylene-dioxy-6, 8-di(γ, γ-dimethylallyl)isoflavone by means of spectral analysis.