Peel of pineapple (Ananas comosus) as a potential source of antioxidants and photo-protective agents for sun protection cosmetics

Abstract

The present study was aimed to evaluate the antioxidant activity and photo-protective property of methanolic extract of pineapple peel to study its potential as a natural source in sun protection cosmeceutical products. The chemical constituents of dried and powdered pineapple peels extracted into methanol by soxhlet extraction were sequentially partitioned into hexane, dichloromethane (DCM) and aqueous methanol (50%). The 50% methanol fraction was found to be rich in phytochemicals with antioxidant activity with IC50 value of 85.70 ± 0.09 μg/mL and the total phenolic content of 208.899 ± 9.388 mg gallic acid equivalent (GAE) / kg dry weight of plant material. DCM fraction was rich in flavonoids with total flavonoid content of 79.913 ± 2.491 mg catechin (CAT) equivalent / kg dry weight of pineapple peel. All the fractions of the pineapple peel were exhibited UV – B protection ability and DCM fraction was consisted with an impressive photoprotective property with the Sun Protection Factor (SPF) of 29.74 ± 0.03 at 1 mg/mL. The aqueous methanol fraction was found to be the most photo-stable after irradiation with direct solar radiation for 21 days. Pearson’s correlation revealed that there is a very strong positive correlation between SPF and TFC (r = 0.9497) and a strong positive correlation between SPF and TPC (r = 0.6366). Since the DCM fraction was rich in compounds with photo-protective properties it was further separated by silica gel column chromatography and analyzed by GC-MS for volatile compounds. The results revealed that the DCM fraction was rich in bioactive compounds with known antioxidant activities indicating the possibility of using pineapple peel to develop natural sunscreen formulations with antioxidant properties.