ABSTRACT
Aim: Traditional plant treatments have been used throughout the world for the therapy of diabetes mellitus. Study Design: Using multiple in vitro models; this study was designed to investigate the efficacy and mode of action of Terminalia chebula Retz. (Combretaceae) used traditionally for treatment of diabetes. Place and Duration of Study: School of Biomedical Sciences, University of Ulster, 2001- 2004. Results: T. chebula aqueous extract stimulated basal insulin output and potentiated glucose-stimulated insulin secretion concentration-dependently in the clonal pancreatic beta cell line, BRIN-BD11 (p<0.001). The insulin secretory activity of plant extract was abolished in the absence of extracellular Ca2+ and by inhibitors of cellular Ca2+ uptake, diazoxide and verapamil, (p<0.001). Furthermore, the extract increased insulin secretion in depolarised cells and augmented insulin secretion triggered by IBMX, but not by tolbutamide or glibenclamide. T. chebula extract did not display insulin mimetic activity but it enhanced insulin-stimulated glucose transport in 3T3 L1 adipocytes by 280% (p<0.001). At (0.5-5.0mg/mL) concentrations, the extract also produced 22-84% (p<0.001) decrease in starch digestion In vitro and inhibited protein glycation (p<0.001) at 1mg/ml aqueous extract. Conclusion: This study has revealed that water soluble bioactive principles in T.chebula extract stimulate insulin secretion, enhance insulin action and inhibit both protein glycation and starch digestion. The former actions are dependent on the bioeffective component(s) in the plant being absorbed intact. Future work assessing the use of Terminalia chebula as dietary adjunct or as a source of active antidiabetic agents may provide new opportunities for the treatment of diabetes
ABSTRACT
Aim: Medicinal, edible and aromatic plants and natural products have been used worldwide for the management of diabetes mellitus. The aim of this study was to investigate the efficacy and mode of action of Emblica officinalis Gaertn. (Phyllanthaceae) used traditionally for treatment of diabetes. Study Design: Using multiple In vitro models; this study was designed to investigate the antidiabetes efficacy and mode of action of E. officinalis. Place and Duration of Study: School of Biomedical Sciences, University of Ulster, 2001- 2004 Results: E. officinalis aqueous extracts (AEs) stimulated basal insulin output and potentiated glucose-stimulated insulin secretion concentration-dependently in the clonal pancreatic beta cell line, BRIN-BD11 (p<0.001). The insulin secretory activity of plant extract was abolished in the absence of extracellular Ca2+ and by inhibitors of cellular Ca2+ uptake, diazoxide (p<0.001, n=8). Furthermore, the extract increased insulin secretion in depolarised cells and further augmented insulin secretion triggered by IBMX and tolbutamide. E. officinalis AE (1 mg/mL) displayed insulin mimetic activity (230%, p<0.001). Furthermore, it enhanced insulin-stimulated glucose transport in 3T3 L1 adipocytes by 460% (p<0.001). E. officinalis augmented also synergistically (p<0.001) insulin action, when co-incubated with insulin sensitizers; metformin (2.4-fold), vanadate (4.9-fold), tungstate (4.8-fold) and molybdate (6-fold). At higher concentrations (0.5-5 mg/mL), the extract also produced 8-74% (p<0.001) decrease in enzymatic starch digestion In vitro. E. officinalis AEs (1-50 mg/mL) inhibited protein glycation 44-87% (p<0.001). Conclusion: This study has revealed that water soluble bioactive principles in E. officinalis extract stimulate insulin secretion, enhance insulin action and inhibit both protein glycation and starch digestion. The former actions are dependent on the bioeffective component (s) in the plant being absorbed intact. Future work assessing the use of Emblica officinalis as adjunctive therapeutic nutraceutical or as a source of bioactive antidiabetic principles may provide new opportunities for the integrated management/prevention/reversal of diabetes.
ABSTRACT
Aims: This study aimed to analyze the chemical composition of essential oil of Pelargonium graveolens L. Her. ex Ait. growing in Jordan and to test the efficacy of the leaves aqueous extract and essential oil against pancreatic triacylglycerol lipase (PL), α- amylase and α-glucosidase. Study Design: GC-MS analysis of the essential oil obtained by hydrodistillation and Solid Phase Microextraction (SPME) methods as well as in vitro enzymatic investigations. Place and Duration of Study: Faculty of Pharmacy, The University of Jordan, between November 2012 and August 2013. Results: The hydrodistilled oil of P. graveolens fresh leaves yielded twenty eight components, accounting for 95.83 % of the total oil content, while thirty seven components were detected from the fresh leaves by SPME (98.86%). Twenty six and thirty one components were identified in the hydrodistilled and SPME oils of the dried leaves amounting to 96.08 % and 97.83 %, respectively. Oxygenated monoterpenes predominated the volatile fractions of the leaves of both methods with citronellol, citronellyl formate and menthone/isomenthone as the major constituents. Similar to orlistat (PL IC50 of 114.0 ± 4.0 ng/mL), P. graveolens extract and volatile oil as well as their purified phyto-constituents inhibited highly substantially in a dose dependent trend PL in vitro (n=3). The P. graveolens extract PL- IC50 was 207.4±15.2 μg/mL. As for their volatile oils’ components, PL- IC50 (%) (V/V) in an ascending order were: menthone; 0.01±0.0 <geraniol; 0.34±0.02 < linalool; 0.7 ± 0.0 < caryophyllene; 1.17±0.12 <P. graveolens oil; 2.93 ± 0.27. Comparable to acarbose, P. graveolens leaves aqueous extracts (AEs) were identified as in vitro potent and efficacious dual inhibitors of α- amylase and α-glucosidase with IC50: 4.6±0.1 mg/mL (p<0.001, n=3). Conclusion: Taken together, P. graveolens leaves, as a nutraceutical modulating gastrointestinal carbohydrate and lipid digestion and absorption, maybe advocated as candidate for obesity-diabetes/metabolic syndrome management.