Antibacterial Activity of Flavans from Crinum distichum

Abstract

The phytochemical study of the ethanol extract from Crinum distichum Herb. was carried out using reversed phase high performance liquid chromatography and afforded a new natural flavan (1), along with (2S)-4'-hydroxy-7-methoxyflavan (2), (2R)-4'-hydroxy-5,7-dimethoxyflavan (3), hippadine (4) and hippacine(5). The structure of the new compound was elucidated using a combination of NMR and HRESI-MS analysis while the structures of the known compounds were established by comparison of their spectroscopic data with those of similar reported compounds. Compounds 2–5 also had moderate activity (32> MIC> 16 μg/mL) against methicillin resistant (MRSA) and methicillin sensitive (MSSA) Staphylococcus aureus (both Gram-positive bacteria), whilst compound 1 was inactive against these two bacterial strains (MIC>128μg/mL). None of the compounds was active against the Gram-negative bacterial strains Escherichia coli and Klesbesiella pneumoniae. The research described herein confirms once more that, plants of the Crinum genus continue to be a rich and underexploited source of new small molecules that could lead to the discovery of new bioactive compounds.