Chemical constituents from leaves of Rhodomyrtus tomentosa / 中草药

ABSTRACT

Objective: To study the chemical constituents from the leaves of Rhodomyrtus tomentosa and its antibacterial activities. Methods: The compounds were isolated and purified by various column chromatographies. Their structures were elucidated by means of spectral analyses (MS and NMR). The antibacterial activity of the compounds was tested by micro dilution method Results: A total of 21 compounds were isolated from the 95% ethanol extract in the leaves of R. tomentosa and identified as (2R,4'R,8'R)-α-tocopherol (1), (2R,4'R,8'R)-β-tocopherol (2), α-tocopherol-quinone (3), α-tocopherol A (4), (-)-a-tocospirone (5), rhodomyrtosone F (6), rhodomyrtosone C (7), watsonianone A (8), rhodomyrtone (9), verimol K (10), methyl cinnamate (11), naringenin (12), quercetin (13), myricetin (14), 3,7,3'-trimethoxy-5,4',5'-trihydroxy flavone (15), 5,7,3',5'- tetrahydroxyflavanone (16), blumeatin (17), dihydroquercetin-7,4'-dimethylether (18), dihydroquercetin-4'-dimethoxy (19), 2,4,7,8,9,10-hexahydroxy-3-methoxyanthracene-6-O-β-L-rhamnopyranoside (20), and 4,8,9,10-tetrahydroxy-2,3,7-trimethoxyanthracene-6-O-β-D-glucopyranoside (21). Conclusion: Compound 6 is a new natural product and compounds 2-5, 10-13, and 15-19 are isolated from the plants of Rhodomyrtus (DC.) Reich for the first time. Compounds 3 and 6-9 exhibit the antibacterial activities.