Three novel quinoline alkaloids from Tetradium glabrifolium and their antibacterial activities

Three novel quinoline alkaloids, tetradiunitiside A (1), tetradiunitiside B (2), glycohaplopine‐6‐O‐α‐L‐rhamnopyranoside (3), along with eight known ones (4‐11) were isolated from the fruits of Tetradium glabrifolium. Their structures were inferred by IR, 1D NMR and 2D NMR and HR‐ESI‐MS spectra. All the isolated compounds were evaluated for the antibacterial activities. Compounds 1‐11 had potential antibacterial activities against Bacillus gasoformans, Bacillus subtilis, Pseudomonas solanacearum and Pseudomonas aeruginosa, with MIC values ranging from 100~3.125 μg/mL. Among them, compound 6 showed the most significant antibacterial activity against four strains bacteria. These findings elucidated the pharmacological substance basis for the antibacterial activity of T. glabrifolium to some extent.