What are the new compounds isolated from the roots of Stemona tuberosa, and what are their structures?

The study investigates the chemical composition of Stemona tuberosa, a plant traditionally used in Asia for its antitussive and insecticidal properties. Previous studies have reported various alkaloids, stilbenoids, phenanthrene, and dehydrotocopherol derivatives from this plant. The current study aims to isolate and characterize new compounds from the roots of Stemona tuberosa. The study successfully identified and characterized new compounds from Stemona tuberosa, contributing to the understanding of its chemical constituents.

The study isolated a new compound, 9,10-dihydro-5-methoxy-8-methyl-2,7-phenanthrenediol (1), and two new optically active compounds, (2S,4'R,8'R)-3,4-δ-dehydrotocopherol (2) and (2R,4'R,8'R)-3,4-δ-dehydrotocopherol (3). The structures of these compounds were determined using spectroscopic data analysis. Compound 1 is a 9,10-dihydrophenanthrene derivative with methoxy and methyl groups at specific positions. Compounds 2 and 3 are stereoisomers of 3,4-δ-dehydrotocopherol, with absolute configurations at C-2 determined by Circular Dichroism (CD) experiments.