Phytochemical investigation, in vitro and in vivo antioxidant properties of aqueous and organic extracts of toxic plant: Atractylis gummifera L

Abstract Ethnopharmacological relevance Atractylis gummifera is a toxic plant widely used in Mediterranean traditional medicine against colds, dizziness, and headaches, as an antisyphilitic, against boils, as a purgative, emetic and deworming. All studies reported on this plant have been carried out either on the plant and its traditional uses, or on cases of poisoning by this plant. However, few pharmacological studies have readjusted the traditional uses of this plant. Aim of the study To valorize Atractylis gummifera from a phytochemical point of view by aqueous and organic extraction and a dosing of phenolic compounds in order to determine the phytochemical composition of the plant. Also, from a pharmacological point of view by evaluating antioxidant activity by five tests in vitro and two tests in vivo in order to build a general idea on the antioxidant power of A. gummifera extracts. Methods The phytochemical study consisted of the hot and cold preparation of aqueous extracts (decocted, infused, macerated) and organic extracts (methanolic, methanolic macerated, chloroformic, ethyl acetate, petroleum ether) and the determination of the secondary metabolites of these extracts. In addition, the biological study consisted of evaluating antioxidant activity in vitro by five different methods (H2O2 radical reduction, DPPH, ABTS, FRAP and RP) and in vivo by SOD and MDA assays. Results The methanolic macerated is the richest in total polyphenols (102 ± 1.38 mg EAG/gE), tannins (144.09 ± 3.96 mg EC/gE) and flavonoids (17.25 ± 0.06 mg ER/gE). The same extract has the highest percentage to inhibit hydrogen peroxide (19.24 ± 1.10%) and the most potent reducing power of the ABTS radical (122.6 ± 0.63 mg ET/gE). We also noted that aqueous macerated has the most potent anti-radical activity of DPPH with an IC50 of 2.78 ± 1.03 μg/ml, the strongest reducing power of iron 96.15 ± 1.12 mg EAA/gE and which was confirmed by the FRAP test (102.5 ± 1.66 mg ET/gE). These results are in agreement with the in vivo study which showed an increase in SOD secretion in diabetic mice treated with aqueous macerated extract (904.26 ± 29.10 units/g liver and 714.16 ± 24.83 units/g kidney) and methanol macerated extract (813.61 ± 24.03 units/g liver and 719.46 ± 42.10 units/g kidney) with a statistically insignificant difference between these two extracts. In addition, we observed a return to normal MDA levels in mice treated with aqueous macerated extract (128.61 ± 15.76 nM/g liver and 103.18 ± 12.67 nM/g kidney) and methanol macerated extract (130.73 ± 10.73 nM/g liver and 34.28 ± 5.73 nM/g kidney). Conclusion The aqueous and organic extracts more particularly those prepared by aqueous and methanolic macerations are rich in polyphenols, flavonoids and tannins, and they represent a rich source of natural antioxidants, also they prevent lipid peroxidation and stimulate the secretion of the enzymatic antioxidant SOD.