Biological activities and chemical composition of Salvia amplexicaulis Lam. extracts

Abstract

This study was aimed to examine chemical composition and biological activities of water, ethanol, methanol, ethyl acetate and dichloromethane extracts of Salvia amplexicaulis Lam. (Lamiaceae). The high performance liquid chromatography (HPLC) analysis showed that the largest amounts of polyphenols were present in methanol extract, followed by ethanol and water extracts, with the kaempferol glycosides as the most abundant components (>40%). Water extract was the most powerful in 2.2-dyphenyl-1-picrylhydrazyl (DPPH), ferric-reducing ability of plasma (FRAP) and β-carotene bleaching antioxidant assays, while the ethanol extract performed the highest activity in 2.2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS) assay. Methanol and water extracts neutralized DPPH radicals more efficiently than standard 3.5-di-tert-butyl-4 hydroxytoluene (BHT) (15.1 μg/mL, 15.8 μg/mL and 17.9 μg/mL, respectively). The antioxidant activity could be possibly attributed to very high content of kaempferol glycosides in the extracts. Ethanol extract was more active against pathogenic bacteria (minimum inhibitory concentrations, MIC, ranged between 30.0 mg/mL and 40.0 mg/mL) than water extract, which was generally stronger antifungal agent (MIC varied from 8.0 mg/mL to 64.0 mg/mL). Water extract also showed stronger cytotoxic activity against HCT-116 cells than ethanol extract (IC50 values were 114.1 μg/mL and 164.5 μg/mL, respectively). The ethanol extract showed slightly stronger antineurodegenerative effects than water extract, especially in tyrosinase inhibition where ethanol extract was considerably effective compared with commercial inhibitor kojic acid. Ethanol and water extracts of S. amplexicaulis showed strong antioxidant and antineurodegenerative activities, which places them among promising natural curative resources for food and pharmaceutical industries.