Sun protection factor, total phenol, flavonoid contents and antioxidant activity of medicinal plants from Iran

Purpose: To evaluate the correlation between sun protection factor (SPF) and the content of phenol and flavonoid and antioxidant activity. Methods: Different parts of 9 medicinal plants were extracted with methanol using three extraction methods (percolation, Soxhlet and ultrasonically assisted extraction) to obtain 42 crude extracts. Their phenol and flavonoid contents, and antioxidant activities were determined using Folin-Ciocalteu reagent, aluminum chloride method and DPPH radical-scavenging activity, respectively. The SPF values were determined and correlated with the phenol and flavonoid contents as well as antioxidant activities. Results: The phenol and flavonoid contents, and antioxidant activities ranged from 54.16-688.97mg GAE/g, 13.38-146.60 mg QE/g and 9.5-1472.4 mu g/mL, respectively while the SPFs were between 0.067 and 0.841. The highest SPF was related to Cucumis melo L. ultrasonically assisted leaf extract (0.841) and Artemisia absinthium L., aerial parts extracted with percolation method (0.717). A significant correlation was found between SPF and phenolic (p=0.003) and flavonoid contents (p=0.023). Conclusion: This study showed a correlation between SPF and phenolic and flavonoid contents. Ultrasonically assisted extract of C. melo leaf has suitable SPF and can be used in sun screen formulations.