Four edible fruits from Vitis vinifera , Punica granatum , Citrus aurantium and Opuntia ficus indica from Algeria were analyzed in order to determine the total polyphenol, total flavonoid and flavonol contents using classical spectrophotometric methods. The antioxidant activity was established by three different single-electron-transfer-based assays (ABTS radical cation, FRAP, and DPPH assays) and one hydrogen-atom-transfer based assay (ORAC). Among the four fruits tested, the Vitis vinifera hydroalcoholic extract showed the highest antioxidant capacity with all methods. The results indicated that the antioxidant activity and the total phenolic content of the selected plants are significantly different ( p < 0.001 ).

Context: The widespread use of Pistacia atlantica Desf. ssp. (Anacardiaceae) in traditional medicine can be partly attributed to the content of its secondary metabolites, in particular, the phenolic compounds.Objective: The effects of harvest period, growing region and gender on the phenolic compounds, flavonoids and condensed tannins contents were studied, as well as on the antioxidant activities of P. atlantica leaves in order to provide a scientific basis for optimal collection.Materials and methods: Leaves were collected monthly from April to October 2010 in two Algerian sites. The powdered leaves were used for preparing the ethyl acetate extract. Contents of total phenolics (TPC), flavonoids (FC) and condensed tannins (CTC) were determined spectrophotometrically. Antioxidant activity was evaluated through radical scavenging activity (RSA) of 2,2-diphenyl-1-picrylhydrazyl (250 μM) and the reducing power capacity (RPC) determination by K3Fe(CN)6 (1%).Results: The TPC was found to vary from 79 ± 13 to 259 ± 8 mg gallic acid equivalents/g of dry weight (DW) during the study period. The RSA and RPC varied between 262 ± 18 and 675 ± 21 mg Ascorbic Acid Equivalent (AAE)/g DW, and from 259 ± 16 to 983 ± 20 mg AAE/g DW, respectively. A seasonal pattern was observed consisting of a decrease in TPC content and RPC from spring to autumn. The FC, CTC and RSA did not show a seasonal pattern.Discussion and conclusion: Our findings showed that secondary metabolite content and antioxidant activities of P. atlantica leaves were more influenced by harvest time and growing region than by gender.

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Response surface methodology in combination with a Box–Behnken design was performed to optimize the extraction conditions, resulting in a maximum total phenolic content yield from Pistacia atlantica leaves.