Evaluation of bioactivities and phenolic composition of extracts of Salvia officinalis L. (Lamiaceae) collected in Montenegro

Sage (Salvia officinalis) is the best-known species of the genus Salvia, due to its medicinal and flavouring properties. This research was conducted on samples of S. officinalis collected from Potoci (SOP) in the continental part of Montenegro and from Valdanos (SOV) and Luštica (SOL) in the country ́s coastal region. Extracts prepared using 96% ethanol, 50% ethanol and hot distilled water were examined for phenolic composition, as well as for their antioxidant, enzyme-inhibiting and cytotoxic activities. The HPLC-DAD method was employed for quantitative-qualitative analysis of phenolic compounds in extracts, which confirmed the presence of rosmarinic and caffeic acids and luteolin-7-O-glucoside. Total phenolic and flavonoid contents, antioxidant activity, and inhibition of acetylcholinesterase and tyrosinase were measured spectrophotometrically. In the applied antioxidant tests (DPPH, FRAP and β-carotene/linoleic acid tests) and tests of inhibition of the enzymes acetylcholinesterase and tyrosinase, the SOP extracts showed stronger antioxidant and enzyme-inhibiting activities compared to SOV and SOL, while the most efficient solvent was 50% ethanol. The highest cytotoxic activity in the MTT test was recorded for 96% ethanol extracts, especially in the case of the SOL sample, against the A375 cell line. All of the tested bioactivities were more strongly correlated with total phenolic content than with flavonoid content. Differences in the tested bioactivities of extracts obtained from plants collected at ecologically different localities and with different extraction solvents could be explained by variations in total phenolic and flavonoid contents.