Biochemical basis of the use of cocoyam (Colocassia esculenta L.) in the dietary management of diabetes and its complications in streptozotocin induced diabetes in rats

Aroids as underexplored tubers with potential health benefits

Colocasia esculenta (L.) Schott and Xanthosoma sagittifolium (L.) Schott are the most popular tubers among the Araceas family. Their chemical composition related to their nutritional benefits could make these rhizomes a valid option for the nutritional and technological improvement of food products. This chapter provide a clarification about the correct nomenclature of both tubers giving an insight around the principle components and their health effects. The scientific literature review has primarily highlighted several in vitro and animal studies where the consumption (leaves and whole tuber) of Colocasia esculenta (L.) Schott and Xanthosoma sagittifolium (L.) Schott was related with certain antihyperglycemic, antihypertensive, hypoglycemic and prebiotic effects. Owing to their functional properties, different component from these rhizomes, specially starch, mucilage and powders are being used by the food industry. Their ability to behave as thickener and gelling agent has allowed their incorporation in baked food, food paste and beverages. This chapter suggests the development of more research around these rhizomes since they could potentially play, with other crops, an important role in the future sustainable strategies to feed the planet.

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.

Balanites aegyptiaca ameliorates insulin secretion and decreases pancreatic apoptosis in diabetic rats: Role of SAPK/JNK pathway

SAPK-JNK pathway performs a significant role in the pathogenesis of type 2 diabetes. Balanites aegyptiaca (BA) is used as an anti-diabetic agent in folk medicine however its hypoglycemic mechanism is not fully elucidated. The current study aimed to evaluate the effect of crude extract, butanol, and dichloromethane fractions from BA on the stress-activated protein kinase/c-Jun N-terminal kinase (SAPK-JNK) pathway in experimental diabetic rats. Six groups of male Wistar rats were included: normal control, diabetic, diabetic rats treated with crude, butanol or dichloromethane fraction from BA (50 mg/kg BW) and diabetic rats treated with gliclazide as a reference drug for one month. Our results suggested a protective role of treatment of diabetic rats with BA against oxidative stress-induced SAPK-JNK pathway. Moreover, BA treatment produced a reduction in plasma glucose, HbA_1c, lactic acid, lipid profile, malondialdehyde levels and produced an increase in insulin, reduced glutathione levels, catalase and superoxide dismutase activities compared with untreated diabetic rats. Moreover, it decreased apoptosis signal-regulating kinase 1, c-Jun N-terminal kinase 1, protein 53 and increased insulin receptor substrate 1 in rat pancreas while it increased glucose transporter 4 in rat muscle. Analysis of BA extracts by LC-HRMS revealed the presence of different saponins with reported hypoglycemic effect. In conclusion, BA exerted hypoglycemic, hypolipidemic, insulinotropic and antioxidant effects. Additionally, it reduced apoptosis in pancreatic β-cells and increased glucose uptake in muscle. These results suggest that the hypoglycemic effect of BA is due to the inhibition of the SAPK-JNK pathway.

Modulation of the lipid profile and insulin levels of streptozotocin induced diabetic rats by ethanol extract of Cnidoscolus aconitifolius leaves and some fractions: Effect on the oral glucose tolerance of normoglycemic rats

BACKGROUND

No study to date has investigated the effect of different polar solvent extracts from Cnidoscolus aconitifolius leaves on glycemic control as used in folk medicine. Hence this study which investigated the effect of ethanol extract and fractions of C. aconitifolius leaves on body weights, relative organ weights, serum levels of glucose, lipid profiles and insulin in streptozotocin induced diabetic rats and on oral glucose tolerance of normoglycemic rats.

METHODS

The ethanol extract was partitioned using methanol, hexane and chloroform to obtain different fractions.

RESULTS

The ethanol extract, fractions or glibenclamide demonstrated hypoglycemic/therapeutic actions as seen from the reduction of serum glucose but increase in serum insulin and body weights of the diabetic rats at the end of experimentation following their administration, unlike the diabetic control that had significant alteration of these parameters with respect to the normal control. Whereas the diabetic control had significant increase in pancreatic weights with no alteration in the heart weights, the ethanol extract, fractions or glibenclamide had no effect on these organs. The ethanol extract, methanol fractions or glibenclamide showed better hypoglycemic actions than the n-hexane or chloroform fractions at the doses used and results obtained were corroborated by histology. Furthermore, the ethanol extract, n-hexane (at 250mg/kg) and methanol fractions or glibenclamide improved glucose tolerance in glucose loaded normal rats. The methanol fraction (500mg/kg) demonstrated anti-hypercholesterolemic, anti-hypertriglyceridemic and insulin modulatory properties in a manner akin to glibenclamide. Acute toxicity study revealed the non toxicity of the plant CONCLUSION: The study justifies the use of polar solvent extracts of this plant in the management of diabetes mellitus.