RESUMO
Phytochemical investigation of the methanol extract of the aerial parts of Lysimachia laxa led to the isolation of four new oleanane-type saponins, lysimosides A-D (1-4) and one known compound, lysimachigenoside B (5). Their structures were elucidated using a combination of HR-ESI-MS, 1D and 2D-NMR spectral data, chemical methods, and comparison with previous literature. The cytotoxic activity of these compounds was evaluated against human lung cancer (A-549) and human breast cancer (MCF-7) cell lines. All compounds exhibited cytotoxic activity against A-549 and MCF-7 cell lines with IC50 values ranging from 6.1 to 16.0 µM, comparable to the positive control, mitoxantrone. Interestingly, oleanane-type saponins with an acetyl group (2-4) exhibited increased cytotoxic activities compared to those without an acetyl group (1).
RESUMO
Seven new oleanane-type triterpene saponins, lysimaponins A-G, were isolated from aerial parts of Lysimachia laxa Baudo. Their chemical structures have been elucidated by analysis of spectroscopic and chemical methods. All compounds were evaluated for their anti-bacterial effects against Microcystis aeruginosa, Vibrio parahaemolyticus, V. harveyi, V. vulinificus, V. cholerae, and V. alginolyticus. All compounds showed potent anti-bacterial activities against the cyanobacteria M. aeruginosa with IC50 values ranging from 14.4 ± 1.2 to 35.3 ± 2.2 µg/mL. Compounds 1, 2, 4-7 inhibited V. parahaemolyticus with MIC values ranging from 64 to 256 µg/mL. The results suggested that saponins from L. laxa could be potential anti-cyanobacteria agents.
RESUMO
In this study, nine triterpene glycosides including seven previously undescribed compounds (1-7), were isolated from leaves of Cryptolepis buchananii R.Br. ex Roem. and Schult. using various chromatographic methods. The chemical structures of the compounds were elucidated to be 3-O-ß-D-glucopyranosyl-(1 â 6)-ß-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (1), 3-O-ß-D-glucopyranosyl-(1 â 2)-ß-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (2), 3-O-ß-D-glucopyranosyl-(1 â 2)-ß-D-glucopyranosyluncargenin C 28-O-ß-D-glucopyranosyl-(1 â 4)-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (3), 3-O-ß-D-glucopyranosyl-(1 â 2)-ß-D-glucopyranosylhederagenin 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (4), 3-O-ß-D-glucopyranosylarjunolic acid 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (5), 3-O-ß-D-glucopyranosyl-(1 â 2)-ß- D-glucopyranosyl-6ß,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (6), 3-O-ß-D-glucopyranosyl-6ß,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (7), asiatic acid 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (8), and 3-O-ß-D-glucopyranosylasiatic acid 28-O-α-L-rhamnopyranosyl-(1 â 2)-ß-D-glucopyranosyl ester (9), through infrared, high-resolution electrospray ionization mass spectrometry, one- and two-dimensional nuclear magnetic resonance spectral analyses. The isolates inhibited nitric oxide production in lipopolysaccharide-activated RAW 264.7 cells, with half-maximal inhibitory concentration (IC50) values of 18.8-58.5 µM, compared to the positive control compound, dexamethasone, which exhibited an IC50 of 14.1 µM.