Résumé:
Within the framework of the valorization of Algerian plant species, and their therapeutic virtues. This work as follow-up of the determinition of secondary metabolites and bioactivities, aims to quantify tannins (hydrolysable and condensed) and assess the antioxydant power by the following methods: total antioxidant activity, metal chelation, and iron reducing power by two methods for ethyl acetate and methanolic extracts of six Algerian species: Nonea vesicaria, Solenanthus lanatus, Cynoglossum cheirifolium, Olea europaea subsp. laperrinei, Rhus pentaphylla and Clematis cirrhosa.
The results obtained show that R. pentaphylla has a high content of hydrolysable tannins for the ethyl acetate extract with a value of 898,64 ± 46,01 mg tannic acid equivalent / g dry extract and condensed tannins for the methanol extract with a value of 32,69 ± 2,63 mg catechin equivalent / g dry extract.
In addition, the results of the antioxidant activity study showed that ethyl acetate and methanol extracts from O. europaea subsp. laperrinei had the highest total antioxidant capacity (780,81± 27,72 and 478,92 ± 19,66 mg ascorbic acid equivalent/g dry extract respectively). The ethyl acetate extract from C.cirrhosa showed a high iron chelation capacity with an IC50 of 762,45 ± 175,31 μg/ml, of which EDTA has the highest iron chelation capacity due to its low IC50 (3,92 ± 0,05 μg/ml). The two tests FRAP and reducing power activity confirmed that extracts of O. europaea subsp. laperrinei have excellent iron-reducing activity. For the FRAP test the methanol extract has a low EC1 (67,93 ± 1,46 μg/ml) and for the reducing power activity test the ethyl acetate extract of O. europaea subsp. laperrinei has a lower EC50 (85,84 ± 6,68 μg/ml) than the positive control trolox (110,10 ± 3,03 μg/ml). Finally, extracts with a high tannin contents and antioxidant activities can find applications in the pharmaceutical and food industry.
