مشخصات پژوهش

This study aims to screen Salvia species to select a plant species with a high level of antioxidant activity and rosmarinic acid content to consider as a potential source for possible use in food industries and human health supplements. For this purpose, eight Salvia species growing widely in Iran were selected to investigate their polar extract in terms of antioxidant activity and rosmarinic acid content. The polar extract of aerial parts of studied plants was obtained by methanol/water (1:1) and their DPPH radical scavenging potential was evaluated. Salvia sclarea showed the highest antioxidant activity and was selected to optimize the ultrasound-assisted extraction process. Antioxidant activity and rosmarinic acid were optimized by response surface methodology to obtain high amounts in the extract. The optimized condition for antioxidant activity was obtained as 40 min, 50% aqueous methanol, 0.1% acid concentration, and 0.07 plant-to-solvent ratio. Antioxidant activity for all studied plants resulted in the range of 1.66 and 0.16 for S. scalarea and S. chloroleuca, respectively. In addition, the optimized condition for rosmarinic acid content was conducted as 30 min, 70%, 0.3%, and 0.05 plant-to-solvent ratio. Rosmarinic acid values in all studied plants were obtained at 0.30 and 23.24 mg g-1 plant dried weight for S. sahandica and S. sclarea, respectively. These findings indicate that optimizing extraction parameters for a distinct compound can be generalized for other plant species in the studied genus. However, optimization for some properties like antioxidant activity which originated from all components in the extract cannot be generalized for other plants. Furthermore, this study suggests that the optimized extract of Salvia sclarea promisingly can be applicable as a source of rosmarinic acid with considerable antioxidant activity in food industries and human nutrition supplements.