Photoprotective and antioxidant effects of Citrus limon and Citrus sinensis Peels: Comparative investigation of the efficiency of five extraction solvents

摘要

© 2022, Indian journals. All rights reserved.Photoaging and photo-carcinogenesis are primarily caused by repeated exposure to ultraviolet (UV) radiation. The use of phytochemical with an antioxidant capacity as photoprotector has increased recently. Citrus fruit’s waste such as peels are considered as one of the resources of antioxidant. The aim of this study was to investigate the effect of five Soxhlet extraction solvents i.e., hexane, chloroform, acetone, ethyl acetate and ethanol on the photoprotective activity of Citrus limon and Citrus sinensis peels. The antioxidant activity of the extract was evaluated using 2,2’-diphenyl-1-pierylhydrazyl (DPPH) assay while photoprotective properties was investigated based on sun protection factor (SPF) and UV absorption ability. The acetone extract of C. limon (IC50:15.30±2.13mg/mL) and C. sinensis (IC50: 26.05±5.19mg/mL) peels exhibited the highest antioxidant activity while ethanolic, ethyl acetate and chloroform extracts of C. sinensis peel exhibited similar scavenging activity with IC50 values ranging between 31-33mg/mL (p>0.05). Hexane extract of both fruit peels showed the lowest antioxidant activity (IC50 >50mg/mL). Interestingly, the opposite was observed in photoprotective activity for C. limon peel extracts with chloroform extract which showed the highest photoprotective activity (SPF:9.06±1.96) followed by hexane (SPF:6.96±0.22), ethyl acetate (SPF:5.11±1.63), ethanol (SPF:4.95±2.38) and lastly acetone (SPF:1.39±0.40). Similarly, acetone extract of C. sinensis peels demonstrated the least photoprotective activity (SPF:1.96±0.28) followed by ethanolic extract (SPF:2.70±0.51). Three extracts i.e., hexane (SPF:6.75±0.33), ethyl acetate (SPF:7.34±0.05) and chloroform (SPF:7.90±0.12) of C. sinensis peel revealed similar potential in photoprotection. The correlation between both DPPH IC50 and SPF values of C. limon and C. sinensis peel extracts are not significant (p>0.05). In terms of UV absorption, all extracts of C. limon peel demonstrated high UV absorption at UVB region (280-320nm) except acetone extract with high UV absorption at UVA region (320-400nm). Meanwhile, all extracts of C. sinensis peel showed broad absorption at UVA and UVC regions with the highest absorption detected at 310-350nm. This finding suggests that ethyl acetate extract of C. sinensis could be used as a natural sunscreen in pharmaceutics due to its valuable antioxidant and photoprotective activities.