Antioxidant, antimicrobial and anti-quorum sensing compounds from Salix babylonica.

Phytochemical investigation of the leaves and bark of Salix babylonica L. trees yielded 11 compounds; catechol (1), methyl trans -4-hydroxycinnamate (2), luteolin (3), apigenin-7- O - β – d -(4″- p- coumaroyl) glucoside (4), populoside B (5), salicin (6), luteolin-7- O - β - d -glucoside (7), catechin (8), acmophyllin B (9), 1- O - p -coumaroyl- β - d -glucopyranoside (10) and chrysoeriol-7- O - β - d -glucuronyl methyl ester (11). Their structures were established using 1D and 2D NMR spectroscopic techniques. Compounds 2, 4, 5 and 8–10 are reported from S. babylonica L. for the first time in this study. Antioxidant activity was determined using in vitro ABTS radical scavenging assay. Compounds 8, 7 and 4 exhibited potent antioxidant activities compared with ascorbic acid. The isolated compounds were screened for their antimicrobial activity. Amongst the tested compounds; compounds 3, 7 and 2 showed the strongest antibacterial activity against Staphylococcus aureus with MIC values of 0.55, 0.70 and 0.88 μmole/L, respectively. Compound 8 exhibited potent anti-quorum sensing activity followed by compounds 7 and 3. Compound 11 , which is a new compound and is thought to be formed as an artifact during the extraction process by the action of the methanol used for extraction, showed cytotoxic activity against HepG2 liver cancer cells and MCF-7 breast cancer cells (IC 50 = 0.210 ± 0.151 and 0.437 ± 0.251 μmole/L, respectively) compared with the standard 5-FU (IC 50 = 0.869 ± 0.066 and 1.257 ± 0.128 μmole/L, respectively). [Display omitted] • The leaves and bark of Salix babylonica L. trees were phytochemically investigated. • Eleven compounds were isolated and were tested for their antioxidant, antimicrobial and anti-quorum sensing activities. • One compound exhibited potent antiquorum-sensing activity followed by two compounds showing strong antiquorum-sensing activity. • Three compounds exhibited potent antioxidant activity compared to that of the standard used ascorbic acid. • One of the compounds showed potent cytotoxic activity against HepG2 liver cancer cells and MCF-7 breast cancer cells. [ABSTRACT FROM AUTHOR]