Antibacterial effects of a new triterpenoid saponin from roots of Gardenia ternifolia Schumach. & Thonn (Rubiaceae)

A new triterpenoid saponin was isolated from Gardenia ternifolia Schumach. & Thonn (Rubiaceae), Ternifoliaoside A 1 together with 8 known compounds 2-9 beta-sitosterol, beta-Stigmasterol-glucoside, 3 beta,23,24-trihydroxyurs-12-en-28-oic acid, 3 beta,19 alpha,23,24-tetrahydroxyurs-12-en-28-oic acid, lippianoside B, silphioside F, copteroside B and 24(24')[Z]-dehydroamarasterone B were isolated from the roots of Gardenia ternifolia Schumach. &Thonn. Compound 1 which is a saponin was reported for the first time in the Gardenia ternifolia species. Their structures were elucidated by analysis of 1D and 2D-NMR studies as well as ESI-MS and HR-FAB-MS. Evaluation of the antibacterial activities of compounds 1, 2, 5, and 9 were performed by the Muller-Hinton agar diffusion method. The microorganisms used were Escherichia coli, Salmonella typhi (Enterobacteriaceae), staphilococus aureaus psodomonase aerogenosae and Vibrion cholorae. No effect was shown on S. aureus, S. typhi, V. cholerae and E. coli with compounds 2 and 9 at different doses: 45 mg/mL, 35 mg/mL, 25 mg/mL and 15 ml/mL. At the highest concentration of 25 mg/ml, compound 5 exhibits the effect on Pseudomonas aeruginosa and Staphylococcus aureus to a diameter of 15.6 +/- 2 mm (Pseudomonas aeruginosa) and 12.2 +/- 2 mm (Staphylococcus aureus). Compound 1 shows very sensitive effect on a Salmonnela typhi and the E. coli strains, respectively at an inhibition diameter of 20.1 +/- 2 mm and 15.40 +/- 2 mm at a concentration of 25 mg/ml.