Variation of antioxidant activity of Salvia leriifolia Benth. root and leaf extracts during the different stages of plant growth

Salvia leriifolia (Lamiaceae) is an endemic plant of Khorasan and Semnan province with antioxidant, antibacterial, antifungal, antidiabetic and antinociceptive properties. In this research, antioxidant activity of root and leaves of S. leriifolia were investigated at different stages of plant growth and development and finally the best time of harvesting for obtaining the maximum antioxidant activity was introduced. For this purpose, plant root and leaves were harvested at vegetative (mid March), flowering (mid April) and ripen seed phases (late May) Then, antioxidant activity in metanolic extract of root and leaves were measured by rancimat method at 110°C. Statistical analysis was performed according to the JMP software. The results showed that maximum antioxidant activity of root and leaves are coincident with vegetative and flowering phase. In vegetative phase, antioxidant activity of the root were significantly higher than the leaves. On the other hand, antioxidant properties of the leaves were markedly stronger than the roots at flowering phase. There was no significant difference between antioxidant activity of the roots and leaves in ripen seed phase. Therefore, it seems that March and April are the best time for obtaining the maximum antioxidant activity of root and leaves, respectively.