Antidiabetic and toxicological properties of some African medicinal plants used in the treatment of diabetes and its complications.

Doctoral Degree. University of KwaZulu-Natal, Durban.This study investigated the antioxidant, antidiabetic and toxicity properties of antidiabetic medicinal plants comprising of Vernonia amygdalina, Cola nitida, Raffia palm (Raphia hookeri) wine, Phaseolus lunatus, Dacryodes edulis, and Clerodendrum volubile using in vitro, ex vivo, in silico and in vivo models. The leaves of V. amygdalina and D. edulis, as well as C. volubile flower were sequentially extracted with solvents of increasing polarity to yield ethyl acetate, ethanol and aqueous extracts. Cola nitida and V. amygdalina were infused in hot water to yield infusion extracts. Phaseolus lunatus was subjected to aqueous extraction to yield aqueous extract, while Raffia palm wine was concentrated to yield the concentrate. The extracts and concentrate were screened for their in vitro and ex vivo antioxidant activities, as well as their inhibitory effect on α-glucosidase, α-amylase and pancreatic lipase activities, and their ability to stimulate muscle glucose uptake and inhibit intestinal glucose absorption in vitro. The ethanol extracts of D. edulis, C. volubile and V. amygdalina were subjected to GC-MS analysis, while the aqueous extract of P. lunatus, palm wine concentrate and the infusions were analyzed with LC-MS to elucidate the active compounds that may be responsible for their bioactivities. The ethanol extracts of C. volubile and D. edulis were further subjected to liquid-liquid fractionation to yield the hexane, dichloromethane, ethyl acetate, butanol and aqueous fractions. These fractions were also assayed for their antioxidant and antidiabetic properties in vitro and ex vivo. The dichloromethane, ethyl acetate and butanol fractions were subjected to GC-MS analysis to elucidate their active compounds. The identified compounds were molecularly docked with the test enzymes in silico to further validate their bioactivities. The antidiabetic properties of palm wine concentrate, C. nitida infusion, and D. edulis butanol fraction were investigated in a type 2 diabetes rat model. The in vivo study revealed a potent hypoglycemic activity, with concomitant amelioration of oxidative stress in the serum, pancreas, testes and brain. This was further substantiated by the downregulation of Nrf2 expressions in the pancreas and brain. These results further validate the use and safety of these plants in diabetes management

Hypoglycemic Potency of Selected Medicinal Plants in Nigeria

A preliminary phytochemical screening and hypoglycemic activities of the ethanolic extracts of phyllanthus niruri, fruits of Solanum melogena var esculentus, leaves and fruits of Solanum Xanthocarpum were investigated. All plant extracts were found to contain alkaloids and tannins, while saponin was found in all plants except Phyllanthus niruri. Coumarin was detected only in Solanum xanthocarpum (leaves), while anthrancenosides was detected in Phyllanthus niruri Solanum xanthocarpum (fruit) only. Hypoglycemic activity of all plants extracts were determined by postprandial glucose test after administration of extracts at 10mg/100g body weight to adult albino rats. Postprandial plasma glucose level was measured at 30 minutes intervals for 2 hours. The result of this study showed that all extracts had hypoglycemic activity with Solanum melongena var esculentus having the highest activity. Thus, the plants may be effective in the management of hyperglycemia may be attributed to the phytochemicals present in them plants

Chemical and functional properties of cassava starch, durum wheat semolina flour, and their blends

High-quality cassava starch (HQCS) produced from high-yielding low-cyanide improved cassava variety, TMS 30572, was mixed with durum wheat semolina (DWS) on a replacement basis to produce flour samples containing 0, 20, 30, 50, 70, and 100% cassava starch. They were analyzed for chemical composition (proximate, amylose, free sugars, starch, wet gluten, and cyanide) and functional properties (pasting, swelling power, solubility, water absorption, water binding, starch damage, diastatic and ?-amylase activity, dough mixing, and stability). Protein, carbohydrate, fat, and ash of flour samples ranged from 0.75–12.31%, 70.87–87.80%, 0.95–4.41%, and 0.12–0.83%, respectively. Cyanide levels in all the flour samples were less than 0.1 ppm. Amylose content varied between 19.49% for cassava and 28.19% for wheat, correlating significantly with protein (r = 0.95, P = 0.004) and ash contents (r = 0.92, P = 0.01) at 5%. DWS and HQCS had similar pasting temperatures (50.2–53°C), while other pasting properties increased with increasing levels of HQCS. Dough mixing stability of samples decreased with increasing levels of HQCS. All the flour samples had ?-amylase activity greater than 200. Both HQCS and DWS compare favorably well in swelling power (7.80–9.01%); but the solubility of wheat starch doubled that of cassava. Starch damage varied between 3.3 and 7.2 AACC for semolina and starch, with the latter having higher absorption rate (97%), and the former, higher absorption speed (67 sec). Results obtained showed positive insight into cassava–wheat blend characteristics. Data thus generated provide additional opportunities of exploiting cassava utilization and hence boost its value–addition potentials for product development

Raffia Palm (Raphia Hookeri) Wine: Qualitative Sugar Profile, Functional Chemistry, and Antidiabetic Properties

Published ArticleThe effects of short-term fermentation on the sugar quality, functional chemistry, antioxidant and antidiabetic properties of Raffia palm (Raphia hookeri) wine were investigated. Palm wine samples were subjected to open air fermentation for 24 and 48 h. The samples showed significant (p < 0.05) antioxidant activities with little or no differences between the unfermented and fermented samples. There was a dose-dependent inhibitory effect on α- glucosidase, α-amylase and intestinal glucose absorption with increasing fermentation time. Both non-fermented and 24 h fermentation led to increased muscle glucose uptake in a dose-dependent manner. 1H NMR spectroscopy showed the presence of allose, cellobiose, d-tagatose, fructose, galactitol, gluconic acid, rhamnose, sucrose, xylose and β-N-acetylglucosamine in the samples. FTIR spectroscopy showed the presence of alcohols, phenols, 1° and 2° amines and aromatics functional groups in all samples. Fermentation led to the addition of the functional group, bend alkenes. These results suggested that un-fermented and fermented Raffia palm wine may have antioxidant and antidiabetic properties

Acalypha wilkesiana ‘Java white’: Identification of some bioactive compounds by GC-MS and their effects on key enzymes linked to type 2 diabetes

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

Chemical Evaluation of African Palm Weevil, Rhychophorus phoenicis, Larvae as a Food Source

The chemical properties of the African palm weevil, Rhychophorus phoenicis (F.) (Coleoptera: Curculionidae), larvae were evaluated using standard methodology. The chloroform-methanol extract yielded 37.12% on a dry basis. The oil was liquid at room temperature with a flash point of 36.0 °C. Analysis of the physical constants indicated values of 192.25 Wijs and 427.70 mg KOH/g as iodine and saponification, respectively. Fatty acid analysis of the extracted oil showed the presence of unsaturated fatty acids at low levels. Palmitic acid and stearic acid constituted 35.3 and 60.5% of the oil, respectively. The usual behaviour of the oil at room temperature, irrespective of the level of unsaturation of its constituent fatty acid was noted. The total protein content of the defatted palm weevil larva (dry basis) was estimated at 66.3%. The amino acid values compared favourably to FAO reference protein, except for tryptophan, which was limiting. All the other essential amino acids were adequate. Mineral analysis revealed high levels of potassium (1025 mg/100 g) and phosphorus (685 mg/100 g). The dried and defatted palm weevil lava represents a very good source of protein, and a good complement of essential amino acids

Short-Term Feeding of Fibre-Enriched Biscuits: Protective Effect against Hepatotoxicity in Diabetic Rats

The effects of fibre-enriched biscuit on biomarkers associated with hepatotoxicity in diabetic rats were investigated. Diabetes was induced by single intraperitoneal injection of alloxan monohydrate. Treatment lasted for 14 days after which the rats were sacrificed by cervical dislocation. Blood serum was analyzed to determine hepatic function enzymes. The liver was also analyzed to determine hepatic lipid profile and antioxidant enzymes. Induction of diabetes led to elevated levels of ALP, AST, and ALT. These were, however, significantly (p<0.05) reduced in the fibre-enriched biscuit fed (treated) group. There was no significant difference in the serum bilirubin and total protein levels of the studied groups. Reduced albumin level was observed in the diabetic group; this was further lowered on feeding with fibre-enriched biscuits. Induction of diabetes led to increased hepatic level of cholesterol, triglyceride (TG), low density lipoprotein (LDL), and lipid peroxidation and decreased activities of glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) and HDL level. These were significantly (p<0.05) reversed on feeding with fibre-enriched biscuit. This study portrays the protective effect of fibre-enriched biscuit on increased oxidative stress and hyperlipidemia in hepatic tissues of alloxan-induced diabetic rats

Efecto de los aceite de soja y de cáscara de naranja (Citrus sinensis) y sus mezclas sobre fosfolípidos totales, peroxidación lipídica y el sistema de defensa antioxidante, en tejidos cerebrales de normo ratas

Soy and orange peel (C. sinensis) oils were fed to albino male rats to determine their effects on malondialdehyde (MDA), total phospholipid (TP) content and oxidative stress biomarkers of brain tissue. Beside mouse chow, four diets were designed to contain 50% of their energy as carbohydrate, 35% as fat, and 15% as protein, and one lipid-free diet which had distilled water substituted for fat. Groups of five rats were each fed one of these diets, while a fifth group was fed pelletized mouse chow. A significant difference (p < 0.05) was observed in the TP of the mouse chow group. The TP was highest (p < 0.05) in those fed the soy and orange peel oil blend as compared to those fed these oils separately. Feeding soy oil led to decreased MDA in brain tissues and influenced the TP content. Significantly lower (p < 0.05) GSH and SOD activities were observed in the groups fed soy oil+orange peel oil, and soy oil diets respectively. Higher significant (p < 0.05) activities were observed in the orange oil fed group. Significantly higher (p < 0.05) catalase activity was observed in the lipid free diet fed group, which was followed by orange peel oil, and soy oil+orange peel oil diets, respectively. A combination of both oils may be useful in the management of certain neurological diseases or illnesses and protect against other oxidative stress complications.Ratas albinas machos fueron alimentadas con aceites de soja y de cáscara de naranja (C. sinensis) para determinar su efecto sobre el malondialdehído (MDA), fosfolípidos (TP) y el contenido total de biomarcadores del estrés oxidativo de su tejido cerebral. Además de alimento para ratones, cuatro dietas fueron diseñadas conteniendo el 50% de la energía en forma de carbohidratos, el 35% en forma de grasa, y el 15% como proteína, y una cuarta dieta libre de lípidos donde se había sustituido la grasa por agua destilada. Grupos de cinco ratas fueron alimentadas cada uno con estas dietas, mientras que un quinto grupo fue alimentado con alimento para ratones peletizado. Se observó una diferencia significativa (p < 0,05) en TP del grupo alimentado concomida para ratón. Los TP fue mayor (p < 0,05) en los alimentados con mezcla de aceite de soja y de cáscaras de naranja, en comparación con los alimentados con estos aceites por separado. La alimentación con aceite de soja llevó a una disminución del MDA en los tejidos del cerebro e influyó en el contenido de TP. Se observó un descenso significativo (p < 0,05) de las actividades de GSH y SOD en los grupos alimentados con aceite de soja+aceite de piel de naranja, y con las dietas de aceite de soja. Se observaron actividades significativamente más altas (p < 0,05) en el grupo alimentado con aceite de naranja. Una actividad catalasa significativamente mas alta (p < 0,05) se observó en el grupo alimentado con una dieta libre de lípidos, seguido por grupo alimentado con aceite de la cáscara de naranja y el que incluía en su dieta la mezcla aceite de soja+cáscara de naranja respectivamente. La combinación de ambos aceites puede ser útil en el control de ciertas enfermedades neurológicas y en la protección contra las complicaciones del estrés oxidativo

Phytochemical studies and antioxidant activity of two South African medicinal plants traditionally used for the management of opportunistic fungal infections in HIV/AIDS patients

<p>Abstract</p> <p>Background</p> <p>It has been observed that perturbations in the antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Hence, the exogenous supply of antioxidants, as natural compounds that scavenge free radicals, might represent an important additional strategy for the treatment of HIV infection. The aim of this study was therefore to analyse the phytochemical constituents and antioxidant potential of <it>Gasteria bicolor </it>Haw and <it>Pittosporum viridiflorum </it>Sims., two South African plants traditionally used for the management of opportunistic fungal infections (OFIs) in AIDS patients.</p> <p>Methods</p> <p>The <it>in vitro </it>antioxidant properties of the two plants were screened through DPPH (1,1-diphenyl-2-picrylhydrazyl), NO (nitric oxide), H₂O₂(hydrogen peroxide) radical scavenging effects and reducing power assays. Phytochemical studies were done by spectrophotometric techniques.</p> <p>Results</p> <p>There were no significant differences in the flavonoid and proanthocyanidins contents between the leaves and bark extracts of <it>Gasteria bicolor </it>and <it>Pittosporum viridiflorum </it>respectively, while the total phenolic content of the bark extract of <it>P. viridiflorum </it>was significantly higher than that of <it>G. bicolor </it>leaf. The acetone extracts of both plants indicated strong antioxidant activities.</p> <p>Conclusion</p> <p>The results from this study indicate that the leaves and stem extracts of <it>Gasteria bicolor </it>and <it>Pittosporum viridiflorum </it>respectively possess antioxidant properties and could serve as free radical inhibitors, acting possibly as primary antioxidants. Since reactive oxygen species are thought to be associated with the pathogenesis of AIDS, and HIV-infected individuals often have impaired antioxidant defenses, the inhibitory effect of the extracts on free radicals may partially justify the traditional use of these plants in the management of OFIs in HIV patients in South Africa.</p