antioxidant and antibacterial activities of six medicinally important species of the genus salvia from north east of iran

this study was carried out to evaluate the antimicrobial and antioxidant effectiveness of different extracts from aerial parts of six salvia species including salvia ceratophylla, salvia chorassanica, salvia leriifolia, salvia macrosiphon, salvia chloroleuca and salvia virgata. the effect of the extracts against 3 gram positive and 3 gram negative bacteria was tested by the micro dilution method. the amounts of total phenolic contents (tpc) extracted from plants in different solvent systems were in the ranges of 11.28- 23.82 (mg gae/g). all extracts showed excellent radical scavenging activity, with ic50 in the ranges 27.38-469.78 μg/ml. the results indicated that methanol extract had the highest total phenolic contents (23.82± 0.16mg gae/g). n-hexane showed maximum ic50 (469.78±5.97μg/ml) value while its antioxidant was lower than the other extracts. among the tested plants, s. chloroleuca, s. virgata and s. ceratophylla were the most active radical scavengers while, s. leriifolia, s. chorassanica and s. macrosiphon were the weaker ones. s. macrosiphon, s. chloroleuca and s. ceratophylla were the most active plants against the growth of gram positive and gram negative bacteria. moreover, it was revealed that aerial parts of the some species belonging to the genus salvia possess some antibacterial as antibiotics principles. the results showed that methanol was the most effective extract with the lowest mic (1.25 mg/ml) against gram positive bacteria. the results of antioxidant activity showed there was not a perfect correlation between total phenolic content and antioxidant activity. the findings of this study scientifically validate the use of salvia species in traditional medicine and may serve as a source of drugs useful in some infections caused by bacteria and also as an antioxidant agent.