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In this study, we identified bioactive compounds from the ethanolic extracts of the leaves, stem bark and root bark of Acalypha wilkesiana through GC-MS analysis and investigated the effects of these extracts on some of the enzymes linked to type 2 diabetes. Plant parts were extracted sequentially with ethyl acetate, ethanol and water. GC-MS analysis revealed the presence of long-chain alkyl acids, esters, ketones and alcohols including phytol and phytol acetate along with some secondary metabolites such as xanthone, vitamin E and various types of sterols including stigmasterol, campesterol and sitosterol. Ethanolic extracts of all the parts showed a dose- -dependent inhibition of α-glucosidase and α-amylase activity. The extracts also demonstrated anti-lipase activity. The ethanolic extract of root bark showed the highest inhibition of enzymes compared to other extracts. The EC50 values (concentrations for 50 % inhibition) of α-glucosidase, α-amylase and lipase inhibition were 35.75 ± 1.95, 6.25 ± 1.05 and 101.33 ± 5.21 μg mL-1, resp. The study suggests that A. wilkesiana ethanolic extracts have the ability to inhibit the activity of enzymes linked to type 2 diabetes. Further studies are needed to confirm the responsible bioactive compounds in this regard.

The effect of Alstonia boonei fractions on glucose homeostasis was investigated via in vitro enzyme inhibition activity, ex vivo glucose uptake assay, and in vivo methods in diabetic rats. A. boonei fractions were subjected to in vitro α-glucosidase inhibitory assay and then ex vivo glucose uptake activity. The butanol fraction of the leaves (ABBF) was picked for the in vivo assay since it showed more activity in the initial tests conducted. ABBF was administrated via oral dosing to six-weeks old fructose-fed STZ-induced type 2 diabetic rats over a 5-week experimental period. ABBF treatment at a low dose of 150 mg/kg bw, significantly (p <.05) reduced blood glucose level, enhanced oral glucose tolerance ability, restored insulin secretion and hepatic glycogen synthesis as well as promoted islet regeneration than the high dose (300 mg/kg bw). These results suggest that ABBF could be exploited as a therapeutic potential for treating T2D. [ABSTRACT FROM AUTHOR]

The antidiabetic potentials of the dichloromethene, ethyl acetate, butanol and aqueous fractions of Bridelia ferruginea leaves were investigated using in vitro, ex vivo and in vivo models. In vitro and ex vivo antidiabetic activities revealed the butanol (BFBF) to be the most active of the fractions, and thus selected for in vivo study. Diabetes was induced using the fructose-streptozotocin model. Treatments with BFBF significantly reduced blood glucose level and improved glucose tolerance, serum insulin level and sensitivity as well as suppressed hyperlipidaemia and serum nephropathy markers. Histopathological analysis revealed the ability of BFBF to protect and regenerate pancreatic β-cells. BFBF significantly elevated glutathione level, catalase and superoxide dismutase activities, while depleting MDA level in serums and kidney of diabetic rats. Phenols, steroids, terpenoids, aliphatic and aromatic compounds were identified in the fractions following GC-MS analysis. Overall, results from this study propose that BFBF possess potent antidiabetic activity. [ABSTRACT FROM AUTHOR]

Crassocephalum rubens (C. rubens) is a traditional leafy vegetables (TLV) eaten in parts of Africa for the management of symptoms of diabetes mellitus. This study was done to investigate the in vivo anti-diabetic activity of the aqueous extract of C. rubens aerial parts (CRAQ). Type 2 diabetes (T2D) was induced in male Sprague Dawley (SD) rats by feeding them with a 10% fructose solution for two weeks followed by single dose (40 mg/kg body weight) intraperitoneal injection of streptozotocin. After confirmation of T2D, animals were treated with a low and a high dose (150 and 300 mg/kg body weight) of extract for five weeks. Parameters used as markers of hyperglycemia were analyzed in the samples collected from rats. Hematoxylin-eosin staining was used in analyzing the morphological changes of the pancreas. Treatment with high dose of the extract significantly (p < 0.05) lowered blood glucose level, increased oral glucose tolerance level and pancreatic β-cell function, while restoring the morphology of the pancreatic tissue damage. The high dose also increased insulin secretion, liver glycogen, antioxidant enzyme activities in serum and organs, and prevented liver and renal damages compared to the untreated diabetic animals. Data from this study suggest that C. rubens possesses impressive anti-diabetic activity and could be useful in ameliorating some complications associated with T2D therefore this plant can be exploited in finding new alternative therapies for the treatment of T2D. [ABSTRACT FROM AUTHOR]

Raffia palm wine is a natural drink from the stem of Raffia palm (Raphia hookeri) tree with nutritional and medicinal properties. The effect of fermentation was investigated on its antidiabetic and antioxidative effects in yeast cells and pancreatic tissues, respectively. Both unfermented and fermented palm wine significantly increased glucose uptake, reduced glutathione level (GSH), superoxide dismutase, and catalase activities. They also inhibited glucose diffusion, myeloperoxidase, and ATPase activities as well as decreased malondialdehyde and nitric oxide levels. They also led to the inactivation of oxidative metabolic pathways in oxidative pancreas with the generation of adenosine, sugar and inositol metabolites, selenium (enzyme co‐factor) and vitamin metabolites owing to concomitant activation of vitamins, lipid, steroids, inositol, and sulfate/sulfite metabolic pathways. The results suggest the antidiabetic and antioxidative potentials of unfermented and fermented palm wine and may be attributed to the LC‐MS‐identified compounds which were mainly polyphenols and its glycosides, vitamins, and amino acids. Practical applications: Raffia palm wine is among the natural beverages employed for social, nutritional, and medicinal purposes. However, there are limited studies on its medicinal properties. This study reports for the first time, the ability of Raffia palm wine to stimulate glucose uptake, inhibit glucose diffusion, and ameliorate pancreatic oxidative injury, as well as the possible associated metabolic pathways that may be involved. These findings will further contribute in understanding the antidiabetic effect of Raffia palm wine, and the possible metabolic pathways involved. [ABSTRACT FROM AUTHOR]

Chronic hyperglycemia has been implicated in the development of oxidative stress and as a major factor in etiology of secondary complication in diabetes. In the present study, the antidiabetic potential of Phragamenthra incana (P. incana) hot infusion and its possible inhibitory effects on carbohydrate digesting enzymes, promotion of muscle glucose uptake, and the antioxidative potentials in Fe 2+ -induced oxidative stress in hepatic tissue were investigated. The infusion significantly (p < 0.05) scavenged free radicals (DPPH) and displayed favourable ferric reducing antioxidant power (FRAP) with increasing concentrations. It also significantly ameliorated Fe 2+ -induced oxidative stress in hepatic tissues by increasing superoxide dismutase (SOD) and catalase activities and depleting malondialdehyde (MDA) level. The results further showed that the infusion significantly (p < 0.05) inhibited α-amylase and α-glucosidase activity, and enhanced muscle glucose uptake, with and without insulin. Liquid Chromatography-Mass Spectroscopy (LCMS) analysis of the infusion revealed the presence of 2-methoxythiazole; l-cysteine; nicotinic acid; S-methyl-l-cysteine; isoquinoline, 1-methyl-; and 1H-indole-2,3-dione,5-methyl. The results of this study suggest that the observed antidiabetic and antioxidative potentials of P. incana could be attributed to its identified phytochemical constituents, however, this supports folkloric medicinal use of this plant., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)