Chidambaram Kumarappan

α-Glucosidase and α-Amylase Inhibitory Activity of Senna surattensis

In this study, we investigated the inhibitory effects of ethanolic extract of the leaves of Senna surattensis (EESS) on α-glucosidase and α-amylase. We also studied the in vitro antidiabetic activity of S. surattensis using the glucose uptake by isolated rat hemidiaphragm model. In vitro studies using mammalian α-glucosidase extracted from the small intestine homogenate of mouse showed that the extract was found to be more effective in inhibiting the activities of maltase [half maximal inhibitory concentration (IC(50)): 209.15 μg/mL] and sucrase (IC(50): 366.44 μg/mL) when compared with the control group (acarbose). The extract of S. surattensis were further quantified with respect to porcine pancreatic α-amylase inhibition using the chromogenic 3,5-dinitrosalicylic acid method. Interestingly, S. surattensis was also found to exhibit α-amylase (IC(50): 123.95 μg/mL) inhibitory activity. The glucose uptake in the rat hemidiaphragm was significantly (p < 0.01) increased by EESS (220.95 ± 5.4 mg/g/30 minute) when compared with the control group. The total polyphenolic content of EESS was found to be 98 μg pyrocatechol/mg of the extract. These results suggest that EESS inhibited carbohydrate digestive enzymes and increased the peripheral uptake of glucose. This study endorses the use of this plant for further studies to determine their potential for managing type II diabetes.

Antioxidant activity of polyphenolic extracts of Ichnocarpus frutescens

In the present study antioxidant activities by (1,1-diphenyl-2-picrylhydrazyl radical (DPPH), hydrogen peroxide, hydroxyl radical inhibition, hemolysis by hydrogen peroxide assay, reducing power and total antioxidant activities of polyphenolic extract of Ichnocarpus frutescens leaves were investigated. The flavonoids and total polyphenolic contents of the extract were also determined using standard methods. Phytochemical analyses revealed the presence of flavonoids, polyphenols, anthocyanins and simple phenolic acids. The results of antioxidant activities of polyphenol extract obtained by different in vitro methods were varied depending on the method used. Nevertheless, polyphenol extract showed significant inhibitory activities in all in vitro reactive oxygen species scavenging, might be attributed due to the high level of polyphenolic compound. Also, these various antioxidant activities were compared to α-tocopherol and l-ascorbic acid as reference antioxidant compounds. These findings provide evidence that the polyphenolic extract of I. frutescens is a natural source of antioxidant against oxidative damage.

Polyphenolic Extract of Ichnocarpus Frutescens Attenuates Diabetic Complications in Streptozotocin-Treated Diabetic Rats

Diabetic nephropathy is one of the major complications of diabetes. Oxidative stress is implicated as an important mechanism by which diabetes causes nephropathy. The aim of the study was to examine the involvement of oxidative stress in the progression of nephropathy in STZ diabetic animals and to evaluate the potential of polyphenolic extract (PPE) in the treatment of diabetes mellitus. In this study, we examined whether prolonged oral administration of polyphenolic extract of Ichnocarpus frutescens could prevent the progress or improve the outcome of diabetic nephropathy induced by oxidative stress in STZ diabetic rats. Intraperitoneal glucose tolerance test (IPGTT) revealed a significant decrease in blood glucose levels at 180 min after glucose loading in Wistar albino rats fed with PPE. During the eight weeks of experimental period, diabetic rats exhibited wide range of symptoms, including loss of body weight, hyperglycemia, polyuria, proteinuria, renal enlargement, and total renal dysfunction. A significant increase in TBARS level was observed in diabetic kidney, which was accompanied by a significant decrease in enzymatic and non-enzymatic antioxidant levels. After eight weeks, PPE-treated groups showed a lower level of blood glucose compared with non-treated STZ diabetic rats. The increases in urinary albumin and protein after eight weeks of treatment were significantly inhibited by prolonged treatment with PPE. In addition, PPE attenuates the adverse effects on hepatic biomarkers. We found that PPE can effectively protect against aldose reductase activity and protein damage (albumin glycation), and showed that its action was mainly due to enriched polyphenolic content. Our results also showed that treatment with PPE normalized the increase in hyperalgesia (i.e., the response to thermal stimuli) associated with the induction of diabetes by STZ. PPE administration in diabetic rats clearly ameliorated diabetic complications, suggesting not only a natural antioxidant but also supportive therapy for the treatment of type II diabetes.

α-Glucosidase inhibitory activity and in vitro antioxidant activities of alcohol-water extract (AWE) of Ichnocarpus frutescens leaves

In this study alcohol–water extract (AWE) of Ichnocarpus frutescens was studied for its α–glucosidase inhibitory activity and antioxidant properties. HAE exhibited the rat intestinal α-glucosidase, sucrase, isomaltase, and maltase activities. Sucrose was administered orally with or without extract to rats at a dose of 1000 mg/kg. The postprandial elevation in the blood glucose level after the administration of sucrose with the extract was significantly suppressed when compared with the control. The antioxidant activity, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide anion radical scavenging , and hydrogen peroxide scavenging activities were evaluated to determine the total antioxidant capacity of the alcohol–water extract. HAE exhibited strong activity in phenyl-hydrazine–induced hemolysis. The total amount of polyphenol compounds in HAE was determined as pyrocatechol equivalents per gram of alcohol–water extract.

Antioxidant Activity of Talinum portulacifolium (Forssk) Leaf Extracts

SUMMARY The aim of the study is to investigate the antioxidant activity through, reducing power, 2, 2diphenyl-1-picryl hydrazyl radical (DPPH), nitric oxide radical (NO), superoxide radical, hydrogen peroxide radical (H O ) scavenging activity and the amount of total phenolic compounds of chloroform, ethyl acetate, methanol and aqueous extracts of the leaves of Talinum portulacifolium. Chloroform extract of leaves of T. portulacifolium showed highest antioxidant activity, with a direct relationship between activity and concentration of extracts (15 - 240 µg/mL). Among all the extracts, the highest amount of the total polyphenolic compounds was found in the chloroform extract. Chloroform extract of T. portulacifolium showed an important free radical scavenging activity towards the DPPH, NO, Superoxide and H O radicals, with IC values of 133.26, 165.75, 156.34 and 135.29 µg/mL, respectively. In the lipid peroxidation assay, extracts of chloroform and ethyl acetate showed a remarkable inhibitory activity. The extracts showed significant activity in all the experiments but lower than the standard antioxidant, ascorbic acid.