Résumé:
Ethnopharmacological relevance: According to Saharian traditional medicine,
Anvillea radiata Coss. & Dur. (Asteraceae) has been valued for treating a variety of
ailments such as gastro-intestinal, liver and pulmonary diseases, and has gained awareness
for its beneficial effect on postprandial hyperglycemia. However, to best of our knowledge,
no detailed study of the antidiabetic curative effects of this plant has been conducted yet.
Aim of the study: To determine the hypoglycemic and antidiabetic effect of dietary
supplementation with Anvillea radiata extracts on high-fat-diet (HFD)-induced obesity and
insulin resistance in C57BL/6 J mice in relation with antioxidant, anti-inflammatory,
pancreatic beta-cells and skeletal muscle protection, and digestive enzyme inhibiting
properties.
Materials and methods: Six extracts (water soluble and organic) from aerial parts
of the plant were analyzed phytochemically (total phenolic and flavonoid content) and
screened for in vitro superoxide (by chemiluminescence) and hydroxyl radical (by electron
paramagnetic resonance spin-trapping) scavenging, antioxidant (DPPH, TRAP and ORAC
assays), xanthine oxidase, metal chelating, α-amylase and α-glucosidase inhibitory
property, and protective effects on copper-induced lipoprotein oxidation. Then selected
hydroalcoholic and aqueous extracts were assessed for toxicity in normal human lung
fibroblasts and A549 cancer cells using FMCA and MTT assays. Two water-soluble
extracts having the best overall properties were assessed for their (i) protective effect at
1−15 µg/mL on metabolic activity of rat insulinoma-derived INS-1 cells exposed to
hyperglycemic medium, and (ii) acute hypoglycemic effect on 16-weeks HFD-induced
diabetic mice. Then diabetic mice were administered HFD supplemented by extracts (up to
150 mg/kg/day) for 12 additional weeks using standard diet as control and the antidiabetic
drug, metformin (150 mg/kg), as positive control. Then the antidiabetic, anti-inflammatory
and antioxidant activity of extracts were determined.
Results: Of the highly efficient polyphenolics-enriched hydroalcoholic and ethyl
acetate extracts, the lyophilized aqueous (AQL) and butanol extracts were not toxic in cells
(≤ 400 µg/mL) or when given orally in normal mice (≤ 2000 mg/kg), exerted a dosedependent hypoglycemic action in diabetic mice, which was maximal at the dose of 150
mg/kg. Upon administering this dose for 12 weeks, both extracts significantly ameliorated
Résumés
body weight control capacity, recovery of plasma glucose and insulin level, reduced
oxidative stress in blood, myocardial and skeletal muscles, and improved hyperlipidemic
and inflammatory status. Moreover, diabetes-related complications were optimally
ameliorated by oral therapy based on halved doses (75 mg/kg) of a mixture of AQL
andmetformin.
