Antioxidant and antibacterial properties of root extracts of Salvia abrotanoides (Kar.) Sytsma

Salvia abrotanoides (Kar.) Sytsma (Russian sage) is one of the Iranian traditional medicinal plant which possesses various bioactivities. In this study, plant roots were collected in seed formation stage from Kalat (Northeast of Iran). Total phenolic and flavonoid contents in ethyl acetate and methanolic extracts of S. abrotanoides roots were determined by colorimetric method. Then, the antioxidative activities of the extracts were evaluated by DPPH radical scavenging activity and thiobarbituric acid reactive substance (TBARS) assays. Besides antibacterial activity of these extracts was investigated against gram negative (Pseudomonas aeruginosa and Escherichia coli) and gram positive (Staphylococcus aureus and Bacillus cereus) bacteria using serial dilution method. Then minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts were determined. Methanolic extract of the roots had more total phenolic compounds but less flavonoids content than ethylacetate extract. In both methods tested, the antioxidant activity of ethyl acetate extract was higher than that of methanolic extract. The IC۵۰ values measured for ethyl acetate extract by DPPH radical scavenging and TBARS assays were ۶۵.۲۱ and ۵.۱۵ μg/mL, respectively. While these values for methanol extract were ۱۳۲.۱۸ and ۱۰.۳۱ μg/mL, respectively. Both extracts of the roots exhibited effective antibacterial activity. The ethyl acetate root extract had stronger antibacterial effect than methanolic one and significantly inhibited the growth of E. coli (MIC and MBC ۰.۱ mg/mL), P. aeruginosa (MIC and MBC ۰.۰۵ and ۰.۱ mg/mL, respectively) and S. aureus (MIC and MBC ۱.۲۵ and ۲.۵ mg/mL, respectively). Whereas B. cereus was more sensitive to the methanolic extract than ethyl acetate extract with MIC and MBC values ۲.۵ mg/mL. In conclusion, the roots of S. abrotanoides, as a good source of natural antioxidant and antibacterial substances, could be considered as potential candidates for further investigations at pharmaceutical and food industries applications.

Keywords:

DPPH , Flavonoid , Russian sage , TBARS , Total phenolic