The in vitro evaluation of antioxidant properties of cachrys libanotis L. roots extracts

Abstract

The aim of this study consisted to evaluate the antioxidant activity of Cachrys libanotis roots extracts, used in folk medicine. The roots were submitted to extraction and fractionation to give crude extract (CrE), chloroformic extract (ChE), ethyl acetate extract (EAE) and aqueous extract (AqE). RP-HPLC analysis revealed the presence of catechin and epicatechin in ChE, and myrectin and gossypin in EAE. The highest total polyphenols and flavonoids amounts were recorded in EAE (83.23 µg gallic acid equivalent/mg of extract and 0.63 µg quercetin equivalent/mg of extract, respectively). Xanthine oxidoreductase (XOR) was purified from bovine milk with yield of 17.97 mg/l, PFR of 7.2, and XOR specific activity of 2261 nmole/min/mg. Both enzymatic and non-enzymatic methods were used to evaluate the antioxidant activity of extracts. Results demonstrated that EAE had the highest XOR inhibitory effect (IC50= 0.11 mg/ml) followed by ChE, CrE and AqE. ChE presented the highest effect both in cytochrome c test and in NBT assay with an IC50 of 0.22 mg/ml and 0.21 mg/ml, respectively. All extracts inhibited linoleic acid oxidation, with remarkable percentage. In fact, the highest effect was showed by EAE (76.21%) followed by CrE and AqE with an approximately similar effect (65.17% and 64.57%, respectively), and ChE (56.95%). DPPH scavenging assay showed that CrE and EAE exhibited the highest effect with an IC50 of 0.41 and 0.59 mg/ml, respectively. Both CrE and AqE had a considerable chelating activity on ferrous iron (Fe+2), 9-folds lower than that of EDTA (IC50= 6.1 µg/ml). Reducing power of extracts was evaluated using FRAP. Extracts exhibited a moderate reducing power, and the highest power was recorded for EAE (TAP= 6.12 mM Fe+2/g of extract). These results can be useful as a starting point of view for further applications of Cachrys libanotis roots in healthcare. In addition, the ability of roots extracts to inhibit XOR can be of great use in some diseases where the inhibition of XOR is warranted.