The influence of goutweed (Aegopodium podagraria L.) tincture and metformin on the carbohydrate and lipid metabolism in dexamethasone-treated rats

Abstract

Background: Diabetes mellitus and metabolic syndrome are the common problems of the modern society. The interest in herbal medicines increases, and often they are used in combination with conventional drugs. Aegopodium podagraria L. (goutweed) is a plant widely used in traditional medicine. Hypoglycemic effect of goutweed aerial part tincture has been previously shown in alloxan-induced diabetic mice and in rats receiving excess of fructose and hydrochlorothiazide. The effects of co-administration of the tincture with widely used antihyperglycemic drugs have not been verified. The objective of this study is to determine the efficacy of goutweed tincture and its combination with metformin using the model reproducing the pathogenetic mechanisms of the metabolic syndrome and type 2 diabetes. Methods: The animals were divided into 5 groups, as follows: intact control, dexamethasone (untreated), dexamethasone + metformin, 50 mg/kg; dexamethasone + A. podagraria tincture, 1 ml/kg intragastrically; dexamethasone + metformin, 50 mg/kg intragastrically + A. podagraria tincture, 1 ml/kg intragastrically. Dexamethasone was used at a dose of 5 mg/kg subcutaneously for 5 days. Insulin tolerance test and oral glucose tolerance test were performed, triglycerides, total lipids, total and HDL cholesterol content in plasma were determined, LDL cholesterol content was calculated, glycogen content in the liver was measured. Results: Goutweed tincture combined with metformin increased its effect on the basal glycemia and on the results of the short insulin test. In the oral glucose tolerance test the lowest area under glucose curve and average glycemia value were seen in animals receiving this combination. Only metformin tended toward the reduction of liver glycogen. The decrease in triglycerides and increment of HDL cholesterol content (caused by the tincture), as well as tendency towards the decrease in total lipids level (caused by metformin) were observed against a background of the investigated combination, though the ability of GW tincture to reduce LDL cholesterol content and the same tendency seen against a background of metformin were eliminated when these preparations were administered together. Conclusion: It has been shown that goutweed tincture combined with the respectively low dose of metformin partially increases the efficacy of the latter in dexamethasone-treated rats. Graphical abstract: Goutweed tincture combined with the respectively low dose of metformin partially increases the efficacy of the latter in dexamethasone-treated rats.