Antioxidant Activity of Extracts and HPLC-DAD-MS Identification of the Major Anthocyanins of the Fruit Peel of Spondias purpurea L. (Anacardiaceae) in Burkina Faso

Abstract

Spondias purpurea L. is an Anacardiaceae fruit species whose peel may contain phenolic pigments of interest, although its phytochemical profile remains insufficiently documented in Burkina Faso. This study evaluated the anthocyanin, phenolic compound and antioxidant contents of the fruit peel and identified the major anthocyanins present. Fresh peel extracts were prepared using acidified methanol and an ethanol-water solvent system. Total anthocyanins were determined by the differential pH method, phenolic compounds by the Folin-Ciocalteu method and antioxidant content by the FRAP assay. Structural identification was performed using HPTLC and HPLC-DAD-MS-visible UV analysis after extraction and acid hydrolysis. The acidified methanol extract contained 7.50 mg cyanidin 3-glucoside equivalents per 100 g of fresh plant material. The phenolic compound and antioxidant contents of the acidified methanol extract were 7.63 mg GAE/g and 6.0 mg TE/g of fresh plant material, respectively, whereas the ethanol-water extract gave lower values. HPLC-DAD-MS analysis indicated three major anthocyanins: peonidin-3-O-galactose, pelargonidin-3-O-glucose and peonidin-3-O-malonoylrhamnose. These results indicate that the fruit peel contains anthocyanins and antioxidant-associated phenolic compounds. Pending structural confirmation by NMR, the peel may be considered a potentially useful plant material for further phytochemical evaluation rather than being treated only as waste.