Antibacterial, antioxidant and cytotoxic activities of triterpenes and flavonoids from the aerial parts of Salvia barrelieri Etl.

Abstract

From the aerial parts of Salvia barrelieri Etl. (Lamiaceae), 12 compounds including a new triterpene, 3β-acetoxy-olean-18-ene-2α-ol, were isolated. Their structures were established by the combination analyses of spectroscopy including 1D-, 2D-NMR and HRESIMS and in comparison with the reported data in the literature. The antibacterial activity of these compounds was evaluated by bioautography on Staphylococcus aureus followed by the determination of MIC values by serial dilution technique against five bacteria. Three compounds were active against Enterococcus faecalis, S. aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa (MIC 15.1 to 125 μg/mL). Two compounds showed moderate DPPH radical scavenging activity (IC₅₀ 79.1 and 21.2 μg/mL). These compounds did not show significant tyrosinase inhibitory activities (IC_50> 1.5 mg/mL). Their cytotoxic activity was evaluated against promyelocytic leukaemia (HL60), human erythromyeloblastoid leukaemia (K562) and fibrosarcoma (HT1080) cell lines and four compounds exhibited a moderate cytotoxic activity (IC₅₀ 28.75 to 85.0 μM).

Keywords:

• Salvia barrelieri
• lamiaceae
• triterpenoids
• flavonoids
• antibacterial activity
• cytotoxic activity
• radical scavenging activity