2-2--azino-di-(3-ethylbenzothiazoline)-6-sulfonic-acid and Diabetes-Mellitus--Type-2

Traditional Indian and Australian medicinal plant extracts were investigated to determine their therapeutic potential to inhibit key enzymes in carbohydrate metabolism, which has relevance to the management of hyperglycemia and type 2 diabetes. The antioxidant activities were also assessed.. The evaluation of enzyme inhibitory activity of seven Australian aboriginal medicinal plants and five Indian Ayurvedic plants was carried out against α-amylase and α-glucosidase. Antioxidant activity was determined by measuring (i) the scavenging effect of plant extracts against 2, 2-diphenyl-1-picryl hydrazyl (DPPH) and 2, 2'-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS) and (ii) ferric reducing power. Total phenolic and total flavonoid contents were also determined.. Of the twelve plant extracts evaluated, the highest inhibitory activity against both α-amylase and α-glucosidase enzymes was exerted by Santalum spicatum and Pterocarpus marsupium with IC50 values of 5.43 μg/ml and 0.9 μg/ml, respectively, and 5.16 μg/ml and 1.06 μg/ml, respectively. However, the extracts of Acacia ligulata (IC50 = 1.01 μg/ml), Beyeria leshnaultii (0.39 μg/ml), Mucuna pruriens (0.8 μg/ml) and Boerhaavia diffusa (1.72 μg/ml) exhibited considerable activity against α-glucosidase enzyme only. The free radical scavenging activity was found to be prominent in extracts of Acacia kempeana, Acacia ligulata followed by Euphorbia drummondii against both DPPH and ABTS. The reducing power was more pronounced in Euphorbia drummondii and Pterocarpus marsupium extracts. The phenolic and flavonoid contents ranged from 0.42 to 30.27 μg/mg equivalent of gallic acid and 0.51 to 32.94 μg/mg equivalent of quercetin, respectively, in all plant extracts. Pearson's correlation coefficient between total flavonoids and total phenolics was 0.796.. The results obtained in this study showed that most of the plant extracts have good potential for the management of hyperglycemia, diabetes and the related condition of oxidative stress.

Topics: alpha-Amylases; Antioxidants; Australia; Benzothiazoles; Biphenyl Compounds; Diabetes Mellitus, Type 2; Enzyme Inhibitors; Ferric Compounds; Flavonoids; Glycoside Hydrolase Inhibitors; Hyperglycemia; India; Magnoliopsida; Medicine, Ayurvedic; Oxidative Stress; Phenols; Phytotherapy; Picrates; Plant Extracts; Plants, Medicinal; Sulfonic Acids; Thiazoles

Ethanolic extracts of 30 Thai medicinal plants, traditionally used as alternative treatments in diabetes, were evaluated for antioxidative activity by the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) method. They were evaluated in vitro for oxidative stress by thiobarbituric acid-reactive substance (TBARS) assay in pooled plasma of diabetic patients compared to without treatment of the extracts (control). The extracts were also assayed for protein glycation. The results showed that five plants had strong antioxidant activity: Phyllanthus emblica Linn. (PE), Terminalia chebula Retz. (TC), Morinda citrifolia Linn. (MC), Kaempferia parviflora Wall. (KP) and Houttuynia cordata Thunb.(HC), respectively. Thirty plant extracts were good correlation between total antioxidant activity and antiradical activity by TBARS as well as by glycation (r = 0.856, p<0.01 and r = 0.810, p<0.01). PE had stronger antioxidative activity as well as inhibition of TBARS and glycation than the other plants. The investigation showed that total polyphenol and tannin content of PE and the flavonoid content of HC were the highest. The results imply that these plants are potential sources of natural antioxidants which have free radical scavenging activity and might be used for reducing oxidative stress in diabetes.

Topics: Antioxidants; Benzothiazoles; Caffeic Acids; Catechin; Diabetes Mellitus, Type 2; Flavonoids; Free Radicals; Gallic Acid; Glycation End Products, Advanced; Humans; Lipid Peroxidation; Medicine, Traditional; Molecular Structure; Oxidative Stress; Phenols; Plant Extracts; Plants, Medicinal; Polyphenols; Pyrogallol; Rutin; Sulfonic Acids; Tannins; Thailand; Thiobarbituric Acid Reactive Substances