Propriétés antioxydantes et activité inhibitrice de la Xanthine oxydase des extraits de la plante médicinale Ajuga iva (L.) Schreber.
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This study was conducted to search for XO inhibitors from Ajuga iva shoot extracts (AISE) traditionally used in folk medicine in Algeria. XO was purified from fresh bovine milk with yields of mg / L, protein / flavine ratio of 5.15 and a single major band, on SDS-PAGE, of approximately 150 KDa, indicating a high purity of the purified enzyme. The specific activity of the purified enzyme was of 2055.05 nmol / min / mg protein. The analysis of methanol (CrE), chloroform (ChE) and ethyl acetate (EaE) extracts, showed that the EaE has significant amount of polyphenols (35.83 ± 0.69 mg EGA / g dry extract), followed by ChE and CrE (30.58 ± 0.2 and 17.38 ± 0.29 mg EGA / g dry extract, respectively). The ChE has the highest flavonoids content (9.64 ± 0.33 mg EQ / g dry extract), followed by EaE and CrE with 7.72 ± 0.19 et 4.92 ± 0.30 mg EQ / g dry extract, respectively. The ChE showed the highest inhibitory properties on the XO activity (IC50 = 0.134 ± 0.00032 mg / ml) and on the cytochrome c reduction (IC50 = 0.23 ± 0.0017 mg / ml), followed by EaE with IC50 of XO inhibitory activity and an IC50 of the inhibition of cyt c reduction of 0.185 ± 0.0019 and 1.046 ± 0.0055 mg /ml, respectively. Finally, CrE had the lowest inhibitory effect on XO activity and on cyt c reduction with 0.367 ± 0.0041 and 3.34 ± 0.018 mg / ml, respectively. The antioxidant potential was confirmed with the non enzymatic methods, DPPH assay and β- carotene / linoleic acid bleaching assay. The highest DPPH radical scavenging activity was observed with EaE (IC50 = 228.01 ± 2.26 µg / ml), followed by CrE and ChE with IC50 of 415.06 ± 0.59 and 466.33 ± 3.20 µg / ml, respectively. The β-carotene / linoleic acid bleaching assay revealed that AISE have a very important antioxidant activity. Results showed that ChE has the highest antioxidant activity (95.64 ± 0.15 %), followed by CrE and EaE with 87.97 ± 0.10 % and 72.30 ± 0.35 %, respectively. These results suggest that these natural products could be used to treat lot of diseases, where inhibition of XO, free radical scavenging activity and / or inhibition of lipid peroxidation are necessary.