Butanol fraction of Alstonia boonei De Wild. leaves ameliorate oxidative stress and modulate key hypoglycaemic processes in diabetic rats.

OBJECTIVE: 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. METHODOLOGY: 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. RESULTS: 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). CONCLUSION: These results suggest that ABBF could be exploited as a therapeutic potential for treating T2D.

Bridelia ferruginea Benth. (Euphorbiaceae) mitigates oxidative imbalance and lipotoxicity, with concomitant modulation of insulin signaling pathways via GLUT4 upregulation in hepatic tissues of diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Bridelia ferruginea Benth. (Euphorbiaceae) is among the medicinal plants commonly used for the management of type 2 diabetes (T2D) and its complications. AIM OF THE STUDY: The hepato-therapeutic effect of the butanol fraction of Bridelia ferruginea leaves was investigated in diabetic rats. METHODS: The butanol fraction of B. ferruginea was given to type 2 diabetic rats at both low and high doses (150 and 300 mg/kg bodyweight, respectively), while metformin and glibenclamide served as the standard anti-diabetic drugs. A normal toxicological group was administered a high dose of the fraction. At the end of the experimental period, the rats were sacrificed, and their livers and psoas muscle collected. The liver was assayed for oxidative stress markers, liver glycogen content, lipid metabolite profile (using GC-MS) and their metabolic pathways were analyzed using the MetaboAnalyst 5.0 online server. The expression of GLUT4 was also assayed in the liver and muscle as well as the identification of signaling pathways associated with GLUT4 expression using the Enrichr online server. In silico molecular docking was used to investigate the molecular interactions of some postulated compound found in B. ferruginea with GLUT4. The ability of the fraction to stimulate muscle glucose uptake was determined in isolated rat psoas muscle ex vivo. RESULTS: Treatment with the high dose of fraction caused an inhibition of lipid peroxidation as well as the elevation of catalase, SOD, glutathione reductase and glutathione peroxidase activities in the rat liver. There was an increased expression of GLUT4 in livers and muscles of diabetic rats following treatment with B. ferruginea. Treatment with the fraction also caused inactivation of diabetes-activated pathways and changes in the distribution of the hepatic lipid metabolites. Molecular docking analysis revealed strong molecular interactions of pyrogallol and sitosterol with GLUT4. CONCLUSIONS: These data illustrate the hepato-protective effect of B. ferruginea in diabetic rats which compare favorably with the tested anti-diabetic drugs (metformin and glibenclamide).

Crassocephalum rubens (Juss. Ex Jacq.) S. Moore improves pancreatic histology, insulin secretion, liver and kidney functions and ameliorates oxidative stress in fructose-streptozotocin induced type 2 diabetic rats.

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 ß-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.

GC-MS metabolomics reveals dysregulated lipid metabolic pathways and metabolites in diabetic testicular toxicity: Therapeutic potentials of raffia palm (Raphia hookeri G. Mann & H. Wendl) wine.

ETHNOPHARMACOLOGICAL RELEVANCE: Raffia palm (Raphia hookeri G. Mann & H. Wendl) wine (RPW) is a natural beverage obtained from the R. hookeri consumed for refreshment and medicinal purposes. For medicinal purposes, it is used singly or as macerating agent for other medicinal plants for the treatment of several diseases. AIM: This study investigates the effect of Raffia palm wine on dysregulated lipid metabolic pathways in testicular tissues of type 2 diabetic (T2D) rats. METHODS: Raffia palm wine (150 and 300 mg/kg bodyweight) was administered to two T2D groups respectively, another T2D group was not administered treatment and served as negative control, while metformin served as the standard drug. After 6 weeks of treatment, the rats were sacrificed, and the testes collected. After weighing, the organs were homogenized in 20% methanol/ethanol and centrifuged at 20,000 g to extract the lipid metabolites. RESULTS: GC-MS analysis of the supernatants revealed an alteration of the metabolites on induction of T2D, with concomitant generation of 10 metabolites. Raffia palm wine inhibited the T2D-generated metabolites while replenishing cholesterol and squalene levels, with concomitant generation of 7 and 8 metabolites for low and high dose treatment respectively. Pathway enrichment analysis of the metabolites revealed a decreased level of steroid biosynthesis and increased level of fatty acid biosynthesis. Raffia palm wine inactivated glycerolipid, fatty acid, and arachidonic acid metabolisms, fatty acid biosynthesis and fatty acid elongation in mitochondria pathways, and activated pathways for plasmalogen synthesis, mitochondrial beta-oxidation of long chain saturated fatty acids. CONCLUSION: The replenishment and generation of these metabolites and additional ones as well as activation of pathways involved in energy generation, phospholipids, antioxidant activity, steroidogenesis and spermatogenesis suggest a therapeutic effect of Raffia palm wine against hyperglycemic-induced testicular dysfunction.

Fractions from Annona muricata attenuate oxidative stress in pancreatic tissues, inhibits key carbohydrate digesting enzymes and intestinal glucose absorption but enhances muscle glucose uptake.

The ameliorating effect of different fractions of Anonna muricata ethanol leaves extract in oxidative pancreatic injury as well as their antihyperglycemic effect were investigated in vitro and ex vivo. Oxidative pancreatic injury was induced by incubating pancreatic tissue with ferrous sulphate (FeSO4 ). The antioxidative potentials of the fractions together with its ability to inhibit carbohydrate digesting enzymes, intestinal glucose absorption, and its ability to modulate muscle glucose uptake were determined. All the fractions significantly scavenge free radicals in dose-dependent manner and increase significantly increase the catalase and superoxide dimutase level thereby ameliorating lipid peroxidation. All the fractions also inihibited glucose digesting enzymes and absorption in dose-dependent manner. Glucose uptake was enhanced by the fractions in isolated psoas muscle of rats. The ethyl acetate fraction showed more potent amelioration and anti-hyperglycemic potentials among all the fractions. This could be further exploited as therapeutic strategy for the management of postprandial hyperglycemia as well as T2D. PRACTICAL APPLICATIONS: Annona muricata is among the edible fruits in the world with reported nutritional as well as medicinal values. The anticancer activity of the leaves and the fruits have been reported. Its ability to inhibit carbohydrate digesting enzymes and absorption and enhancing muscle glucose uptake as well as protection of pancreatic ß-cell from oxidative damage further support its reported antidiabetic properties. A. muricata provided a cheap and alternative source of nutraceuticals, which could be further exploited as therapeutic strategy for the treatment of postprandial hyperglycemia in T2D.

Hyperglycemia-induced oxidative brain injury: Therapeutic effects of Cola nitida infusion against redox imbalance, cerebellar neuronal insults, and upregulated Nrf2 expression in type 2 diabetic rats.

The therapeutic effect of the hot water infusion of Cola nitida against hyperglycemia-induced neurotoxicity, cerebellar neurodegeneration and elemental deregulations was investigated in fructose-streptozotocin induced rat model of type 2 diabetes (T2D). A diabetic group was administered drinking water, two other diabetic groups were treated with C. nitida at 150 and 300 mg/kg bodyweight respectively, while another group was administered metformin (200 mg/kg bodyweight). Two other groups consisting of normal rats, were administered drinking water and C. nitida (300 mg/kg bodyweight). After 6 weeks of treatment, their brains were collected. Treatment with C. nitida led to suppression of oxidative stress, significantly elevating reduced glutathione (GSH) levels, superoxide dismutase and catalase activities, concomitant with depletion of malondialdehyde (MDA) levels. Acetylcholinesterase and ATPase activities were significantly inhibited in C. nitida-treated diabetic rats. Histological and microscopic analysis also revealed a restorative effect of C. nitida on T2D-altered distribution of elements, neurons and axonal nodes. Treatment with C. nitida also led to significant inhibition of Nrf2 expression in the cerebellar cortex. These results suggest the therapeutic effects of C. nitida in maintenance of the neuronal integrity and antioxidant status of the brain in T2D. These neuroprotective activities can be attributed to the identified alkaloid, caffeine in the infusion.

Raffia palm (Raphia hookeri G. Mann & H. Wendl) wine modulates glucose homeostasis by enhancing insulin secretion and inhibiting redox imbalance in a rat model of diabetes induced by high fructose diet and streptozotocin.

ETHNOPHARMACOLOGICAL RELEVANCE: Raffia palm (Raphia hookeri) wine (RPW) is amongst the natural products from plants, utilized singly or in combination with other medicinal plants for the treatment of several ailments including Diabetes Mellitus (DM). However, there is a scientific dearth on its antidiabetic activity. AIM: The antidiabetic effect of RPW and its possible mechanism of actions were investigated in diabetic rats. METHODS: Four groups of male SD rats were first supplied with 10% fructose solution ad libitum for 2 weeks instead of drinking water followed by an intraperitonial injection of streptozotocin (40 mg/kg) to induce diabetes. Two diabetic groups were administered RPW at 150 and 300 mg/kg bodyweight (BW) respectively; a group was administered with metformin, while the other one was served as a negative control. Two groups of normal rats were administered with water and RPW (300 mg/kg BW) and served as normal control and normal toxicology group, respectively. RESULTS: Five weeks treatment of RPW led to significant (p < 0.05) increase in serum insulin and HDL-c levels with concomitant reduction in blood glucose, fructosamine, ALT, uric acid, triglycerides and LDL-c levels in diabetic rats. Rats treated with RPW had elevated levels of GSH, SOD, catalase, ATPase and α-amylase activities, while reduced NO level and myeloperoxidase activity was observed in their serum and pancreatic tissues. RPW also improved pancreatic ß-cell function and restored ß- and acinar cells morphology, and capillary networks. The activities of glycogen phosphorylase, fructose 1,6 biphosphatase, glucose-6-phosphatase, and acetylcholinesterase were also inhibited in RPW-treated diabetic rats, with concomitant down regulation of Nrf2 gene expression. CONCLUSION: The data of this study suggest that RPW modulates glucose homeostasis by enhancing insulin secretion as well as inhibiting redox imbalance in diabetic rats, which may be attributed to the synergetic effects of its phytochemical constituents as identified by GC-MS analysis.

Vernonia Amygdalina Del. stimulated glucose uptake in brain tissues enhances antioxidative activities; and modulates functional chemistry and dysregulated metabolic pathways.

Brain glucose uptake is usually reduced in type 2 diabetes owing to downregulation of brain glucose transporters. The ability of Vernonia amygdalina to stimulate glucose uptake as well as ameliorate glucose-induced oxidative stress and proinflammation were investigated in rat brain. Hot infusion of V. amygdalina leaves was incubated with rat brain tissues for 2 h in the presence of glucose. Another incubation with glucose only, served as negative control while metformin served as positive control. Incubation of brain tissues with V. amygdalina led to significant (p < 0.05) increase in glucose uptake, reduced glutathione, nitric oxide and non-thiol proteins levels, superoxide dismutase, catalase and ATPase activities, while concomitantly decrease in myeloperoxidase activity and malondialdehyde level compared to the negative control. Incubation with glucose only, led to the development of nitrate, amide II and amide I functional groups which were removed on incubation with the infusion. LC-MS analysis revealed depletion of oxidative stress-induced 2-keto-glutaramic acid and cysteinyl-tyrosine metabolites in brain tissues, with concomitant generation of S-formylglutathione and adenosine tetraphosphate by the infusion. Pathway analysis of the metabolites revealed an activation of pyruvate metabolism pathway in the negative control, with the infusion reducing the intensity fold. LC-MS analysis of the infusion revealed the presence of l-serine, l-cysteine, l-proline, nicotinic acid, cumidine, salicylic acid, isoquinoline, 3-methyl-, and γ-octalactone. Except for l-serine, l-cysteine and l-proline, the other compounds were predicted to be permeable across the blood brain barrier. These results indicate the brain glucose uptake stimulatory and neuroprotective effect of V. amygdalina.

Flowers of Clerodendrum volubile modulates redox homeostasis and suppresses DNA fragmentation in Fe2+ - induced oxidative hepatic and pancreatic injuries; and inhibits carbohydrate catabolic enzymes linked to type 2 diabetes.

INTRODUCTION: Medicinal plants have long been recognized for their roles in the treatment and management of diabetes and its complications. The antioxidative and antidiabetic properties of Clerodendrum volubile flowers were investigated in vitro and ex vivo. METHODS: The flowers were sequentially extracted with solvents of increasing polarity (n-hexane, ethyl acetate, ethanol and water). The concentrated extracts were subjected to in vitro antioxidant assays using the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging and Ferric reducing antioxidant power (FRAP) protocols. Their inhibitory activities were investigated on α-glucosidase, pancreatic lipases, pancreatic ATPase and glucose-6-phosphatase activities. Their anti-oxidative and anti-apoptotic effects on Fe2+-induced oxidative injuries were also investigated in pancreatic and hepatic tissues ex vivo. RESULTS: The extracts showed potent free radical scavenging activity and significantly (p < 0.05) inhibited all studied enzymes. The GSH level was significantly (p < 0.05) elevated in both tissues with concomitant increase in superoxide dismutase (SOD) and catalase activities as well as reduced levels of malondialdehyde (MDA). The extracts significantly (p < 0.05) suppressed DNA fragmentation in hepatic tissue. These activities were dose-dependent. The ethanol extract showed the best activity and can be attributed to the synergetic effect of its chemical constituents identified via gas chromatography-mass spectroscopy (GC-MS). CONCLUSION: These results suggest the antioxidative, antidiabetic and anti-obesogenic potentials of C. volubile flowers.

Concentrated hot water-infusion of phragmanthera incana improves muscle glucose uptake, inhibits carbohydrate digesting enzymes and abates Fe2+-induced oxidative stress in hepatic tissues.

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 Fe2+-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 Fe2+-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.

Boerhaavia diffusa inhibits key enzymes linked to type 2 diabetes in vitro and in silico; and modulates abdominal glucose absorption and muscle glucose uptake ex vivo.

The present study investigated the in vitro and ex vivo antioxidant, anti-diabetic and anti-obesogenic potentials of different solvent (ethyl acetate, ethanol and water) extracts from the aerial parts of Boerhaavia diffusa. The ferric reducing antioxidant power (FRAP), DPPH scavenging activity and the ameliorative effects of the extracts on Fe2+-induced oxidative injury was investigated both in vitro and ex vivo. Alpha glucosidase and pancreatic lipase inhibitory potentials of the extracts were examined in vitro, while the effects of the ethanol extract on abdominal glucose intake and muscle glucose uptake were determined in freshly harvested tissues ex vivo. The extracts were subjected to Gas Chromatography-Mass Spectrometry (GC-MS) analysis to identify their possible bioactive components. The ethanol extract showed the most potent FRAP and DPPH radical scavenging activities compared to other extracts. All extracts increased catalase and SOD activities, and GSH levels in oxidative pancreatic injury. Both ethanol and aqueous extracts exhibited remarkable enzyme inhibitory activities, which was significantly higher than ethyl acetate extract and acarbose but was not comparable to orlistat. The ethanol extract portrayed a dose-dependent inhibitory effect on jejunal glucose uptake and enhancement of muscle glucose uptake. 9-(4 methoxyphenyl) xanthene, xanthone and stigmasterol showed strong binding affinities for α-glucosidase and lipase enzymes tested. Data from this study suggest that aerial parts of B. diffusa (particularly the ethanol extract) may not only exhibit antioxidant potentials but may also mediate anti-lipidemic and anti-hyperglycemic effects via inhibiting fat and carbohydrate digestion as well as abdominal glucose intake and enhancing muscle glucose uptake.

Acalypha Wilkesiana 'Java White': Identification of Some Bioactive Compounds by Gc-Ms and Their Effects on Key Enzymes Linked to Type 2 Diabete.

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.

Caffeine - rich infusion from Cola nitida (kola nut) inhibits major carbohydrate catabolic enzymes; abates redox imbalance; and modulates oxidative dysregulated metabolic pathways and metabolites in Fe2+-induced hepatic toxicity.

The antioxidative and antidiabetic effects and toxicity of caffeine-rich infusion of Cola nitida were investigated using in vitro, ex vivo and in silico models. C. nitida was infused in boiling water and allowed to cool before concentrating at <50°C. HPLC analysis of the infusion revealed a caffeine content of 80.08%. The infusion showed potent in vitro antioxidant activity by significantly (p<0.05) scavenging 2,2'-diphenyl-1-picrylhydrazyl (DPPH). It significantly (p<0.05) inhibited α-glucosidase and α-amylase activities. Treatment of Fe2+ induced oxidative hepatic tissues with the infusion led to increase Superoxide Dismutase (SOD) and catalase activities, and glutathione (GSH) level as well as decreased malondialdehyde (MDA) level. FTIR spectroscopy of hepatic metabolite revealed restoration of oxidative-induced depleted functional groups by the infusion. LC-MS analysis of the metabolite also revealed restoration of most depleted metabolites with concomitant generation of 4-O-Methylgallic, (-)-Epicatechin sulfate, L-Arginine, L-tyrosine, Citric acid and Decanoic acid in infusion-treated tissues. Pathway analysis of the identified metabolites revealed the presence of 21 metabolic pathways involved in normal hepatic tissues, 12 in oxidative injured tissues and 17 in the treated tissues. Treatment with the infusion restored 4 metabolic pathways common to the normal tissue and further activated 4 additional pathways. Prediction of oral toxicity of caffeine showed it to belong to class 3, with a LD50 of 127mg/kg. Its toxicity target was predicted as Adenosine Receptor A2a. It was also predicted to be an inhibitor of CYP1A2. These results suggest the antioxidative and antidiabetic properties of C. nitida infusion, with caffeine as the major constituent.

Dacryodes edulis enhances antioxidant activities, suppresses DNA fragmentation in oxidative pancreatic and hepatic injuries; and inhibits carbohydrate digestive enzymes linked to type 2 diabetes.

The leaves of Dacryodes edulis were investigated for their anti-oxidative and anti-diabetic potentials in vitro. Extracts from sequential extraction with solvents of increasing polarity (n-hexane, ethyl acetate, ethanol and aqueous) of the leaves were subjected to in vitro antioxidant assays using the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging and Ferric reducing antioxidant power (FRAP) protocols respectively. Their inhibitory effects were investigated on α-glucosidase, pancreatic lipases, pancreatic ATPase and glucose-6-phospatase activities. Their antioxidant and anti-apoptotic effects on Fe2+ - induced oxidative injuries in pancreatic and hepatic tissues were also investigated ex vivo. The ethanol extract was subjected to Gas chromatography mass spectroscopy (GC-MS) and Fourier transform infrared (FTIR) spectroscopic analysis to identify its bioactive chemical constituents. The extracts showed potent free radical scavenging activity and significantly (p<0.05) inhibited all studied enzymes, with the ethanol extract showing greater activities. Superoxide Dismutase (SOD) and Catalase (CAT) activities were significantly (p<0.05) increased in both pancreatic and hepatic tissues with concomitant elevation of reduced glutathione (GSH) levels as well as reduced levels of malondialdehyde (MDA). The extracts significantly inhibited DNA fragmentation. These activities were dose - dependent. Amongst compounds identified, only Kaur-15-ene, Urs-12-ene-3-ol acetate and 2,3,23-trihydroxyolean-12-en-28-oic acid methyl ester showed strong binding affinities when docked with α-glucosidase (PDB ID:3TON). These results indicate the anti-oxidative, anti-diabetic and anti-obesogenic potentials of D. edulis leaves, which gives credence to its antidiabetic folkloric claims.