A new bibenzyl and 9,10-dihydrophenanthrene derivative from aerial parts of crowberry (Empetrum nigrum L.)

Abstract

• A new methoxylated bibenzyl and 9,10-phenanthrene were isolated from the shoots of Empetrum nigrum . • Structures of the isolated compounds were elucidated by spectroscopic methods. • The first time 1-(3-hydroxyphenyl)-2-(3-hydroxy-4,5-dimethoxyphenyl)ethane was shown to be contained in E. nigrum . Two new natural products - 1 and 2 , together with four known compounds ( 3-6 ) were isolated from aerial parts of crowberry ( Empetrum nigrum L.). All structures were elucidated by extensive 1D and 2D NMR experiments and HR-ESIMS data along with comparison of their spectroscopic data with those reported in the literature. Compound 1 (1-(3,5-dihydroxy-4-methoxyphenyl)-2-phenylethane) is a bibenzyl (dihydrostilbene) derivative. Compound 2 was found to be 6-hydroxy-2,3,4-trimethoxy-9,10-dihydrophenantrene. Compounds 3 and 4 were established as 4,7-dihydroxy-2,3-dimethoxy-9,10-dihydrophenantrene (ephemeranthol-A) and 1-(3-hydroxyphenyl)-2-(3-hydroxy-4,5-dimethoxyphenyl)ethane, respectively. Compounds 5 and 6 were identified as 4′-hydroxy-2′-methoxydihydrochalcone and 2′,4′-dihydroxychalcone, respectively.