Ocena działania przeciwcukrzycowego ekstraktów otrzymanych z wybranych surowców roślinnych

Abstract

Introduction. Diabetes is characterized by chronic hyperglycaemia, resulting from a defect in insulin secretion or abnormal functioning of this hormone. The consequence of the lack of insulin is the disturbed metabolism of carbohydrates, proteins and fats. Chronic hyperglycemia causes damage and dysfunction of many organs. One of the ways to support the treatment of diabetes is the use of plant preparations. Aim. The aim of the study was to examine and compare the biological (α-glucosidase and antioxidative) activity and the content of polyphenols and flavonoids in selected plants: Anserinae herba, Alchemillae herba and Fragariae folium, included in herbal tea blends used in diabetes. Material and methods. The content of polyphenols was determined by applying the Folin-Ciocalteu reagent and the flavonoid content by the AlCl3 method. The antioxidant properties were tested using the reagent method DPPH and CUPRAC, while the inhibitory activity of α-glucosidase by measuring the absorbance of p-nitrophenol from PNPG released by hydrolysis of sugars by the enzyme. Results. High total polyphenols content in the tested plant extracts was found, amounting to 121.30; 98.30; 71.66 mg gallic acid equivalent/g for Alchemillae herba, Fragariae folium and Anserinae herba, respectively, and high flavonoid content (17.56, 12.25, 15.48 mg quercetin equivalent/g, respectively). Antioxidant activity for extracts with a concentration of 0.312 mg/ml was from 46.22 to 79.71% (in the analysis with DPPH radical), while the absorbance value of these tests determined by the CUPRAC method was A = 0.49-1.01. The effect was weaker than vitamin C. The results indicated a strong inhibitory ability of α-glucosidase, which was > 98% for all tested extracts at the concentration of 0.1 mg/ml, and was many times higher than the standard acarbose analyzed at the above concentration, and comparable with the acrabose activity at a concentration of 10 mg/ml. Conclusions. The inhibitory α-glucosidase and antioxidant activity indicates the existence of this mechanism included in analyzed plant extracts, as ingredients herbal tea blends of used in diabetes.