<i>In vitro</i> and <i>in vivo</i> evaluation of antidiabetic potential of extracts of selected medicinal plant preparations collected from Nigerian traditional medical practitioners

Abstract

Background: Diabetes mellitus is one of the main chronic diseases worldwide. It is characterized by persistent hyperglycaemia. Individuals with persistent  hyperglycaemia are at high risk of developing complications (blindness, leg  amputations and kidney failure). Nigeria is 1 of 4 highly populated countries in  Africa with the largest number of people with diabetes mellitus majority of who use plant extracts given to them by traditional medical practitioners (TMPs).
Objectives: To assess the antidiabetic potential of extracts of selected Nigerian medicinal plant recipes collected from TMPS.
Materials and Methods: Eighteen recipes (maximum 2 plants) were selected after an ethnobotanical survey of medicinal plant recipes used by TMPs in the management of diabetes mellitus in the 6 geopolitical zones of Nigeria. Recipes were extracted in water according to traditional usage and screened in vitro to assess glucose uptake in C2C12 muscle cells and glucose production by the H4IIE liver cells (through inhibition of glucose-6-phosphatase, the rate limiting enzyme) and in vivo through the oral glucose tolerance test in normal mice (2 g/kg glucose).
Results: Two extract recipes (NC01 and NC09E) stimulated glucose uptake in  C2C12 cells, 5 (NW14, NE15, NC01, SE01 and NW01) reduced glucose production in H4IIE cells and 4 (SE04, SE11, NC01 and NC09E) prevented hyperglycaemia in glucose-loaded normal mice. Conclusion: Only a few of the extracts from the recipes collected from the TMPs showed antidiabetic activity by increasing glucose uptake in the muscle (11%), reducing glucose production in the liver (28%) and/or preventing hyperglycaemia (22%).

Keywords: Diabetes mellitus, Recipe extracts, Glucose uptake, Glucose production, Oral glucose tolerance test