Effect of cocoyam (Colocasia esculenta), unripe plantain (Musa paradisiaca) or their combination on glycated hemoglobin, lipogenic enzymes, and lipid metabolism of streptozotocin-induced diabetic rats

Functional foods of sub-Saharan Africa and their implications in the management of type 2 diabetes: A review

Throughout the world, the prevalence of metabolic diseases in general and type 2 diabetes (T2DM) in particular is constantly growing, and sub-Saharan Africa (SSA) is not spared. The use of functional foods is a more practical option among the different approaches used in the management of T2DM owing to the fact that they are relatively less costly, safer, and more accessible. In addition to their low glycemic index just like foods currently used to manage diabetes, functional foods contain bioactive compounds such as polyphenols, dietary fibers, saponins, and peptides. They are so named because they have additional health advantages beyond their basic nutritional worth. Bioactive compounds can be found in a variety of SSA plant-based foods, such as spices, fruits, vegetables, legumes, starchy foods, prepared foods, mixed foods, and prepared dishes. The goal of this review is to highlight some of the investigations into the effectiveness of local food and their antidiabetic mechanisms that have been studied in various SSA regions. Using the literature review as a basis, the authors state that SSA foods are rich in various bioactive compounds capable of regulating blood sugar through enhanced glucose tolerance, antioxidant effects, insulin sensitivity, and inhibition or activation of some key enzymes of the glucose metabolism that are linked to the prevention and management of T2DM. Many of the cited findings are preliminary, obtained from cell and preclinical studies, and therefore other studies need to be done to demonstrate the full potential of these foods to serve as bases for dietary guidelines.

Tert-butylhydroquinone abrogates fructose-induced insulin resistance in rats via mitigation of oxidant stress, NFkB-mediated inflammation in the liver but not the skeletal muscle of high fructose drinking rats

The effect of 21% fructose drinking water (FDW) (w/v) on some parameters of metabolic syndrome, hepatic, and skeletal muscular histology of rats was studied using standard techniques. Twenty male albino rats were divided into four groups of 5 rats each in this in vivo study. Group I received distilled water, group 2 received FDW, group 3 received FDW and metformin (300 mg/kg body weight daily, orally), group 4 received FDW and 1% tert-butylhydroquinone feed. FDW changed the serum leptin, triacylglycerol, very low-density lipoprotein, and C-reactive protein levels of the rats, inducing hypertriglyceridemia, oxidative stress, and inflammation in their liver (but not the skeletal muscle) and insulin resistance which were modulated with metformin and tBHQ as corroborated by liver and muscle histology. The study reveals the potentials of metformin and tBHQ in mitigating hepatic and skeletal muscular morphological changes arising from exposure to high fructose drinks. PRACTICAL APPLICATIONS: There has been an increase in the global consumption of fructose (either as a sweetner in beverages or soft and carbonated drinks) in the last few decades and this has been positively correlated with the global increase in metabolic complications. Regular intake of fructose contributes to the pathogenesis of lipid disorders, oxidant stress, and chronic inflammation, which are linked with the metabolic syndrome components (MetS) (obesity, insulin resistance, and cardiovascular diseases) as well as increased morbidity and mortality. Given that the approaches that have been applied to treat the MetS have not been able to totally arrest it, currenty study which showed that tBHQ abrogated fructose-induced insulin resistance, dyslipidemia, hepatic, and skeletal muscular pathology in the rats places tBHQ in the spotlight as a nutraceutical that could be of relevance in mitigating high dietary fructose-induced hepatic and skeletal muscular pathology.

Cocoyam (Colocasia esculenta) modulates some parameters of testosterone propionate-induced rat model of benign prostatic hyperplasia

The increased global prevalence of benign prostatic hyperplasia (BPH) and the promising potentials of functional foods in ameliorating it led to this study which reported the effect of aqueous ethanol extract of cocoyam (Colocasia esculenta) tuber on some biochemical indices in testosterone propionate (TP) induced benign prostatic hyperplasia (BPH) rats. Thirty male albino rats were randomly assigned into 6 groups of 5 rats each. Group 1 (negative control) received 3 mg/kg of TP and normal saline, group 2 (positive control) received 3 mg/kg of TP and 5 mg/kg of finasteride; groups 3, 4, and 6 rats received 3 mg/kg of TP and 100, 200 and 400 mg/kg of ethanol extracts of cocoyam respectively while group 5 (normal control) received olive oil + normal saline. The study lasted for 28 days. The negative control had increased prostate weight (p < 0.05), decreased body weight gain, prostatic superoxide dismutase, catalase and glutathione concentrations; no differences (p > 0.05) in the serum total cholesterol, triacylglycerol, Very Low Density Lipoprotein, High Density Lipoprotein, Low Density Lipoprotein concentration but increased (p < 0.05) prostate levels of interleukin 10, prostate specific antigen, testosterone, total proteins and malondialdehyde relative to the normal control. Finasteride or the C. esculenta tuber extract modulated most of these parameters as corroborated by histology of the prostate. The percentage yield of the C. esculenta tuber extract was 1.56% and 23 phenolic compounds were characterized in the tuber. The study showed the potentials of C. esculenta tuber in the management of BPH.

Anticancer and Immunomodulatory Benefits of Taro (Colocasia esculenta) Corms, an Underexploited Tuber Crop

Taro corms contain valuable bioactive molecules effective against cancer and cancer-related risk factors, such as carcinogens and biological agents, several pathophysiological conditions, including oxidative stress and inflammation, while controlling metabolic dysfunctions and boosting the immunological response. Such broad effects are achieved by the taro health-influencing compounds displaying antitumoral, antimutagenic, immunomodulatory, anti-inflammatory, antioxidant, anti-hyperglycemic, and anti-hyperlipidemic activities. Taro bioactivities are attributed to the combination of tarin, taro-4-I polysaccharide, taro polysaccharides 1 and 2 (TPS-1 and TPS-2), A-1/B-2 α-amylase inhibitors, monogalactosyldiacylglycerols (MGDGs), digalactosyldiacylglycerols (DGDGs), polyphenols, and nonphenolic antioxidants. Most of these compounds have been purified and successfully challenged in vitro and in vivo, proving their involvement in the aforementioned activities. Although these health-promoting effects have been recognized since ancient times, as well as other valuable features of taro for food profit, such as hypo-allergenicity, gluten-free, and carbohydrates with medium-glycemic index, taro crop remains underexploited. The popularization of taro intake should be considered a dietary intervention strategy to be applied to improve the overall health status of the organism and as supportive therapy to manage tumorigenesis.

Characterization of the natural products in cocoyam (Colocasia esculenta) using GC-MS

CONTEXT

There is paucity of information in literature on the natural products in cocoyam [Colocasia esculenta Linn (Araceae)] that confer it with biological properties.

OBJECTIVES

This study investigated the antioxidant properties of C. esculenta and also reported for the first time the natural products in C. esculenta that justify its biological properties.

MATERIALS AND METHODS

The antioxidant activity of the methanol extract (50-250 μg/mL) of C. esculenta was determined using the 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical and reducing power assays. Characterization of the natural products in C. esculenta was done using the gas chromatographic-mass spectrometric (GC-MS) technique. The experiment lasted for 3 months.

RESULTS

GC-MS analysis of methanol/chloroform extract of the flour of C. esculenta indicated the presence of eight compounds, namely hexadecanoic acid methyl ester (0.43%), octadecanoic acid (20.91%), 9,12-octadecadienoyl chloride (0.77%), 11-octadecenoic acid methyl ester (2.12%), 9-octadecenoic acid (64.37%), 3-hexadecyloxycarbonyl-5-(2-hydroxylethyl)-4-methylimidazolium(1.36%), hexanedioic acid, bis(2-ethylhexyl)ester (1.36%) and 3,5-di-t-butyl phenol (3.27%). The total phenolic content of C. esculenta was 15.15 ± 0.35 mg Gallic Acid Equivalence/g and it was significantly higher (p < 0.05) than the total flavonoid (8.50 ± 0.42 mg Quercetin Equivalence/g) and condensed tannin (4.40 ± 0.14 mg Catechin Equivalence/g) contents, respectively. C. esculenta possessed strong antioxidant capacity though it was lower than that of standard quercetin.

DISCUSSION AND CONCLUSION

Results showed that C. esculenta possesses strong antioxidant activity and also contains some important bioactive compounds that justify its medicinal properties as used in ethno-medicine.

Gmelina arborea Roxb. (Family: Verbenaceae) Extract Upregulates the β-Cell Regeneration in STZ Induced Diabetic Rats

Gmelina arborea Roxb. (common name: Et-demata, Family: Verbenaceae) has been used traditionally in Sri Lanka as a remedy against diabetes mellitus. The objective of the present study was to evaluate antidiabetic mechanisms of the aqueous bark extract of G. arborea in streptozotocin induced (STZ) diabetic male Wistar rats. Aqueous bark extract of G. arborea (1.00 g/kg) and glibenclamide as the standard drug (0.50 mg/kg) were administered orally using a gavage to STZ diabetic rats (65 mg/kg, ip) for 30 days. The antidiabetic mechanisms of aqueous extract of G. arborea (1.00 g/kg) were determined at the end of the experiment. The fasting blood glucose concentration was significantly lowered and the serum insulin and C-peptide concentrations were increased by 57% and 39% in plant extract treated rats on day 30, respectively (p < 0.05). The histopathology and immunohistochemistry results of the plant extract treated group showed a regenerative effect on β-cells of the pancreas in diabetic rats. In addition, serum lipid parameters were improved in G. arborea extract treated diabetic rats. The results revealed that the aqueous stem bark extract of G. arborea (1.00 g/kg) showed beneficial effects against diabetes mellitus through upregulating the β-cell regeneration and biosynthesis of insulin in diabetic rats.