Three Novel Quinoline Alkaloids From Tetradium glabrifolium and Their Antibacterial Activities

Three novel quinoline alkaloids, tetradiunitiside A ( 1 ), tetradiunitiside B ( 2 ), and 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 their antibacterial activities. Compounds 1–11 had potential antibacterial activities against Bacillus gasoformans , Bacillus subtilis , Pseudomonas solanacearum , and Pseudomonas aeruginosa , with minimum inhibitory concentration (MIC) values ranging from 100 to 3.125 µg/mL. Among them, compound 6 showed the most significant antibacterial activity against four strains of bacteria. These findings elucidated the pharmacological substance basis for the antibacterial activity of T. glabrifolium to some extent. Graphical Three novel quinoline alkaloids together with eight known ones were isolated from the fruits of Tetradium glabrifolium . The antibacterial activity of compounds against four bacteria strains were screened, and 11 compounds exhibited significant antibacterial activity.