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This study was conducted to provide basic information for conservation and restoration through investigation of vegetation structure on the Euchresta japonica Hook. f. ex Regel (Korean endangered species) in Mt. Halla in Jeju Island. Very few individuals were discontinuously distributed and restricted at 220 m above sea level, very steep slope (40-50°), rocky area of north face of Donneko Valley. For investigation of environmental condition, we established 10 × 20 m quadrat and one control 20 × 20 m quadrat in the habitats. Thirty three species were found at habitat under 10-16 m Castanopsis sieboldii tree layer (70-80%). The principal causes of threat which were investigated in this study are competition among companies, very steep slopes, artificial management of valley. For restoration and conservation of habitats, it is needed to suitable plans.

We isolated 13 microsatellite loci from Euchresta japonica, an endangered shrub species that grows in warm-temperate forests in East Asia. Of these 13 loci, only one was codominant and polymorphic with five alleles. Cross-species amplification in a related species, E. formosana, detected nine of these loci, all of which were codominant and polymorphic with 2 to 9 alleles. These markers will facilitate further studies on the genetic characteristics of these two Euchresta species.

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

The taxonomic position ofEuchresta trifoliolata is discussed, and it is concluded that it is identical withE. japonica. Consequently,E. japonica can be considered to be discontinuously distributed between SW. Japan and S. China and represents a unique pattern of distribution, which has not been known for the flora of Japan and China.E. japonica is also considered to represent a relic distribution pattern.

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.

A new isoprene substituted flavanone ( 1), named cudraflavanone A, was isolated from the root bark of CUDRANIA TRICUSPIDATA (Carr.) Bur. together with three known flavonoids, cycloartocarpesin ( 2), populnin ( 3), and quercimeritrin ( 4). The structure of 1 was determined on the basis of the spectral evidence and the total synthesis. The structure of euchrestaflavanone C ( 5) which had been isolated from EUCHRESTA JAPONICA Hook, f. ex Regel was also determined on the basis of the total synthesis.

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.

The structure of a novel highly substituted coumaronochrome, designated as euchretin A, from the stems of Euchresta japonica was established by spectral evidences. Its antibacterial activity is also described