Résumé:
Medicinal plants are frequently used in Algeria, in particular for the treatment of type 2 diabetes.
Two ethno-botanical surveys of patients and traditional herbalists have permitted to select many plants with potential effect. The three plants most frequently cited were studied: Artemisia herba-alba Asso (AHA), Centaurium erythraea Rafn. (CE) and Trigonella foenum-graecum L. (TFG). In order to verify the reality of the biological effects, we have tested preventive and curative effects of hydroalcoholic extracts of these plants in type 2 diabetes induced by a high fat diet in C57BL/6J mice. Extracts of plants were prepared by hydro-alcoholic maceration of the aerial parts of AHA and CE and seed of
TFG followed by evaporation and were then freeze-dried. High fat diet in untreated mice resulted in increasing body weight (122,2 ± 25,4 % or 132,6 ± 20,0 % in preventive and curative groups respectively), hyperglycaemia with insulin resistance and hypertriglyceridemia. Plants extracts were administered orally by gavage at a dose of 2 g/Kg bodyweight daily from the start of the high fat diet (preventive), or at the 17th week when diabetes was established (curative). Plants extracts show a
late anorexigenic effect in preventive treatment but an immediate effect in curative treatment.
In the preventive treatment, only AHA and CE extracts prevent the onset of hyperglycaemia, insulin resistance, with the least body weight increase, no effect on HDL-cholesterol or leptine. TFG extract had no effect in preventive treatment on glycaemia. In curative treatment, AHA, CE and TFG extracts normalized glycaemia and insulin resistance with no notable effect on body weight. Beside these, extracts had other effects on studied parameters except HDL-cholesterol and leptine. Plants extracts can oppose the effects of high fat diet and the development of type 2 diabetes (AHA and CE) or treat (AHA, CE and TFG) established diet with little or no effect on body weight. The extracts appear to inhibit absorption of the glucose or increase its peripheral metabolism without increasing insulin secretion. The nature and the action mechanisms of the compounds involved need to be specified, and the effect of these plants confirmed in human diabetics subjects.
