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.