Phenolic Contents and Antioxidant Properties of Aqueous and Organic Extracts of a Moroccan Ajuga iva Subsp. Pseudoiva

Abstract

Aerial parts of Ajuga iva subsp. Pseudoiva were screened for phytochemical composition using plant powder, and aqueous and organic extracts and their antioxidant activities were evaluated by hydrogen peroxide radical scavenging activity (H2O2), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2ʹ-azinobis-3 ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity, ferric reducing/antioxidant power (FRAP) assay, and reducing power (RP) assay. The macerated methanol extract was rich in polyphenols (25.26 ± 0.95 µg gallic acid equivalent per milligram of extract), the ethyl acetate extract was rich in flavonoids (821.43 ± 1.65 µg quercetin per milligram of extract), and chloroform extract was rich in catechin tannins (95.58 ± 1.69 µg catechin equivalent per milligram of extract). Methanol macerate had a free radical scavenging activity of 22.17 ± 0.30% by H2O2 assay; methanol extract was found to be the most active by DPPH (IC50 = 78.40 ± 5.24 µg mL−1), RP (21.55 ± 0.18 µg Ascorbic Acid Equivalent (AAE) mg−1 E), and FRAP [22.70 ± 0.19 µg Trolox equivalent per milligram of extract (TE mg−1 E)] assays and chloroform extract was found to be the most active by ABTS (27.33 ± 1.08 µg TE mg−1E) assay. A positive correlation was established by the Pearson correlation test between polyphenol contents and antioxidant capacity by ABTS test. There is also a good correlation between the tests used to evaluate antioxidant activity, with the exception of the two tests DPPH and ABTS, which do not correlate with each other.