Assessment of Chemical Composition and in vitro Antioxidant Activity on Different Varieties of Almond (Prunus amygdaloides schltr.)

Six different varieties of Almond (Prunus amygdaloides) such as Patasa, Surkh talwar, Safaid talwar, Aroo, Kaati and Pewand of Loralai Balochistan were analyzed for determination of heavy metals (Zn, Fe, Cr, Co, Pb, Cd and Cu), by atomic absorption spectrometry and total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing ability of plasma) assay. By following two step extraction method free and bound fractions were obtained from almonds (with and without brown skin individually) with two solvents i.e. acetone and water. A minute difference was found between free and bound phenolics whereas contents of bound flavonoids were much more high than free flavonoids. Comparison between acetone and water extracts of with and without skin samples showed that acetone extracts of almond samples (with skin) represents comparatively high TPC, TFC and antioxidant activity. ‘Patasa’ was ranked first for displaying high antioxidant capacity as well as high concentration of TPC (920.95 ± 9.3 mgGAE/100g DW) and TFC (117.99 ± 1.9 mgQE/100g DW) among all the varieties. Strong positive correlations between phytochemicals and antioxidant activity proved that phenolics and flavonoids either in free or in bound form are good scavengers of free radicals and help in the inhibition of diseases that are caused by oxidative stress. The results for heavy metals indicated that the amount of Cu was high in all varieties while the Surkh talwar accumulated higher concentration of Zn, Cd and Cu.