Phenolic Composition and Anti-tyrosinase Activities of Extracts from Tunisian Opuntia ficus-indica Flowers Obtained by Different Extraction Solvents

The plant genus Opuntia ficus-Indica has been used in traditional folk medicine for the treatment of many diseases and pathological conditions. In the current work, three different Opuntia ficus-Indica flower extracts (methanol, ethanol, and Acetone) were studied for their phytochemical composition, phenolic profile, and tyrosinase inhibitory potential. The results of phytochemical analyses show that acetonic extract has the highest total phenolic content of 757.67 ± 1.21 mg GAE/g of extract and total flavonoid content of 179.00 ± 0.58 mg QE/g of extract. The HPLC–MS analyses of phenolic compounds allowed the identification and quantification of ten compounds mainly identified as isorhamnetin glycosylated derivatives, kaempferol, and Quercetin and rutin. In this study, we aimed to investigate the tyrosinase inhibitory activity of Opuntia ficus-indica flowers extracts; the acetonic extract showed the highest inhibitory activity with IC50 value of 0.285 ± 0.03 mg/ml followed by methanolic extract with IC50 value of 0.625 ± 0.02 mg/ml and ethanolic extract with IC50 value of 0.875 ± 0.04 mg/ml. Those findings suggest that Opuntia ficus-Indic flowers extracts could be a potential natural source of bioactive compounds with a variety of biological activities such as anti-tyrosinase which justifies its use in traditional medicine.