Antioxidant activities and anti-inflammatory effects of Ammodaucus leucotrichus Coss. &Durieu extracts

Abstract

Ammodaucus leucotrichus Coss. & Durieu (Apiaceae) is traditionally used in southern Algeria to decrease blood glucose levels along with a wide range of physiological disorders due to its health-promoting properties. This study aims to validate the traditional claims of this species through in vitro and in vivo evaluation of antioxidant and anti-inflammatory potentials of plant methanolic extract and its fractions, together with assessment of the safety profile. Plant seeds were subjected to methanolic maceration followed by liquid- liquid scale extraction using solvents of different polarity to afford:crude extract (CrE), chloroform extract (ChE), ethyl acetate extract (EAE) and aqueous extract (AqE). Among these extracts, the highest contents of polyphenols and flavonoids were recorded in the crude extract (77.14 ± 0.01 µg GAE/mg E and 19.59 ± 0.08 µg QE/mg E, respectively). CrE and its fraction were qualitatively and quantitatively analyzed regarding their phenolic compounds by HPLC-ESI-MS/MS.Results indicated that caffeic, ferulic and vanillic acids were the major phenolic acids alongside with flavonol kaempferol. Anti-radical activity was assessed in vitro using DPPH•, ABTS•+, H2O2, OH•, O2•- and NO•. EAE was the most active and potent radical scavenger. Meanwhile, EAE and ChE showed a high inhibition percentage at an early stage of β-Carotene/linoleic acid coupled oxidation with 81.99 ± 2.942% and 78.24 ± 1.46 %, respectively. These two fractions showed remarkable protection of linoleic acid against lipid peroxidation even after 96 h, where MDA absorbance values were very low. Metal chelating showed that AqE was the effective extract. However, in ferric reducing ability, EAE performed the best reducing activity with EC50 of 0.12 ± 0.002 mg/ml. All extracts effectively protected mice erythrocytes against AAPH-induced hemolysis in a concentration-dependent manner. EAE and CrE similarly dissociated the formed clot with a comparable percentage of 19.93% and 19.92%, respectively, reflecting their antithrombotic activity. While EAE and ChE showed partial blood clotting even after 3 h of observation.All plant extracts performed a noticeable ????-amylase inhibition. Where EAE showed the best inhibition activity with 0.63 ± 0.003 mg ACAE/g E against ????-amylase and 1.31 ± 0.037 mg ACAE/g E against ????-glucosidase. CrE and its fractions ffectively protected the HSA structure in thermal conditions even at low concentration (0.31 mg/ml). Oral administration of 200 mg/kg of crude extract successfully inhibited acetic acid-induced nociception and reduced edema formation induced by xylene and carrageenan. However,a dose-dependent manner was observed to decrease ear edema by a microscopic examination in croton oil-induced acute inflammation. Nitrite (NO2-) and MDA levels were decreased together with restoration of catalase activity by CrE administration.According to OECD guidelines, acute toxicity was performed at two limit tests; 2 g/kg and 5 g/kg where no signs of changes in animals’ behavior nor mortality were observed indicating CrE as a non-toxic substance. Sub-acute toxicity confirmed the safety use of CrE at repeated doses (100, 200 and 400 mg/kg) on a daily basis by lacking toxic signs regarding animals’ body weight and organs relative weight. In addition, histological analysis showed the absence of treatment-related changes in livers and kidney sections. Administration of CrE decreased MDA and NO2- levels and improved the cellular status of enzymatic antioxidants through enhancement of SOD, CAT, GPx and GST activities in the liver and kidney. To conclude, this study corroborated those bioactive compounds, mainly polyphenols and flavonoids, from this plant as antioxidant and anti-inflammatory agents with a safe profile and supports the use of this plant in folk medicine.