A new lignan glycoside from Astragalus yunnanensis.

A new lignan glycoside, astrayunoside A (1), along with eight known compounds (2-9), were obtained from the methanol extract of roots of Astragalus yunnanensis. All the compounds were obtained from A. yunnanensis for the first time. Their structures were elucidated by extensive spectroscopic analysis (1D and 2D-NMR, MS, UV, CD, and IR). The weak antibacterial activities of the crude extracts of A. yunnanensis against Staphyloccocus aureus, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Shigella dysenteriae, Salmonella typhi H901, Candida albicans, Streptococcus mutans, and Actinomyces viscosus were observed.