Chinedum Eleazu

Review of the mechanism of cell death resulting from streptozotocin challenge in experimental animals, its practical use and potential risk to humans.

Streptozotocin (STZ) (2-deoxy-2-({[methyl(nitroso)amino]carbonyl}amino)-β-D-glucopyranose) is a naturally occurring diabetogenic compound, produced by the soil bacterium streptomyces achromogenes, that exhibits broad spectrum of antibacterial properties. Streptozotocin functions as a DNA synthesis inhibitor in both bacterial and mammalian cells. In mammalian cells, the actual mechanism and metabolic targets of STZ toxicity that results in cell death is not known. This review identifies four key areas that explain the mechanism of the cytotoxicity of STZ in mammalian cell lines, investigates the practical aspects of using STZ in experimental animals and the potential risks of its exposure to human health.

Effect of Partial Replacement of Wheat Flour with High Quality Cassava Flour on the Chemical Composition, Antioxidant Activity, Sensory Quality, and Microbial Quality of Bread

In the current study, wheat flour was mixed with high quality cassava flour (HQCF) in several ratios: 90:10, 80:20, 70:30, and 60:40, and used to prepare 10%, 20%, 30%, and 40% National Root Crops Research Institute (NRCRI) cassava bread, respectively. 100% wheat bread was prepared as a control (100% wheat bread). Five bread samples were prepared per group. Antioxidant assays [i.e., 2,2-diphenyl- 1-picrylhydrazyl radical (DPPH) scavenging assay, reducing power assay] revealed that the bread samples had considerable antioxidant capacities. Substitution of wheat flour with HQCF at various concentrations resulted in dose dependent decreases in the mineral and protein contents of the resulting bread samples. The crude fiber content of the bread samples was minimal, while the carbohydrate content of the bread samples ranged from 43.86% to 48.64%. A 20% substitution of wheat flour with HQCF yielded bread samples with a general acceptability that was comparable to that of 100% wheat bread. The mean bacteria counts of the bread samples ranged from 2.0×103 CFU/mL to 1.4×104 CFU/mL, while the fungal counts ranged from 0 CFU/mL to 3×103 CFU/mL. There was a positive correlation between the DPPH antioxidant activities and the reducing powers of the bread samples (R2=0.871) and a positive correlation between the DPPH antioxidant activities and the flavonoid contents of the bread samples (R2=0.487). The higher microbial load of the NRCRI cassava bread samples indicates that these bread samples may have a shorter shelf life than the 100% wheat bread. The significant positive correlation between total flavonoid content and reducing power (R2=0.750) suggests that the flavonoids present in the lipophilic fractions of the bread samples could be responsible for the reductive capacities of the bread samples.

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.

The role of dietary polyphenols in the management of erectile dysfunction–Mechanisms of action

The incidence of erectile dysfunction (ED) is on the increase and it is estimated that it will affect about 322 million men globally by the year 2025 if adequate measures are not taken to curb it. Natural polyphenols in plant based diets have gained public interest in recent times due to their roles in the prevention of various disease that implicate free radicals/reactive oxygen species and recently on ED. However, the role of polyphenols in the management of ED has not been explored due perhaps to limited data available. Hence this study which reviewed the role of dietary polyphenols in the management of ED and their mechanisms of action. Literature search was carried out in several electronic data bases such as Pubmed, Google Scholar, Medline, Agora and Hinari from1972 to 2016 to identify the current status of knowledge on the role of polyphenols in the management of erectile dysfunction. Progress made so far in this direction suggests inhibition of arginase, acetylcholinesterase, angiotensin converting enzyme, rho-kinase II; activation of endothelial and neuronal NO synthase; decreased synthesis of luteinizing hormone and testosterone reduction; activation of silent information regulator 2-related enzymes (sirtuin1) as well as free radical/reactive oxygen species inhibition as the mechanisms through which the polyphenols identified in this review exert beneficial roles in the management of ED.

Effect of kolaviron, a biflavanoid complex from Garcinia kola on some biochemical parameters in experimentally induced benign prostatic hyperplasic rats

BACKGROUND To determine the effect of kolaviron on some biochemical parameters in benign prostatic hyperplasia (BPH) rats. METHODS BPH was induced in rats using a mixture of dihydrotestosterone and estradiol valerate (10:1). RESULTS The lethal dose of kolaviron was 3050mg/kg body weight. Body weights, relative heart weight (RHW), relative liver weight (RLW), serum levels of prostate specific antigen, prolactin, estradiol, testosterone, testosterone/estradiol ratio, aspartate transaminase (AST), alanine transaminase (ALT), urea, creatinine and prostatic levels of total proteins in the normal rats administered finasteride (standard drug) or kolaviron were not different (P>0.05) from normal control whereas most of these parameters were altered in the disease control except RHW, RLW, AST and ALT. Finasteride (5mg/70kg) or kolaviron (100 and 200mg/kg) ameliorated most of these parameters compared with disease control except RHW, RLW, prolactin, AST, ALT, urea and creatinine (for kolaviron at 100mg/kg). The normal rats administered finasteride or kolaviron had decreased prostate weights (P<0.05) compared with the normal control which results were corroborated by histological assay that also showed that treatment with kolaviron (200mg/kg) or finasteride reversed the histoarchitecture of the prostates of the BPH rats. CONCLUSION Kolaviron could be useful in the management of BPH.

Effect of livingstonepotato (Plectranthus esculenthus N.E.Br) on hyperglycemia, antioxidant activity and lipid metabolism of streptozotocin induced diabetic rats

Highlights • Streptozotocin induced diabetes altered fasting blood glucose, glycated hemoglobin, body weight, serum lipid profiles, hepatic lipogenic enzymes and antioxidant activities of the rats.• Livingstone potato modulated the fasting blood glucose, glycated hemoglobin, lipid profiles, hepatic lipogenic enzymes and antioxidant status of the diabetic rats.• Treatment of diabetics with livingstone potato may lead to increased utilization of circulating glucose by the liver.

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

Abstract Objective To investigate the biochemical basis of the anti-diabetic action of cocoyam [ Colocassia esculenta ( C. esculenta )] in streptozotocin diabetic rats. Methods Blood glucose of the rats was measured with a glucometer. The relative heart weight, relative pancreatic weight, serum proteins, urea, creatinine, albumin, amylase, lipase, serum and hepatic aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and chemical analysis of the test feed were determined using standard techniques. Results The diabetic rats fed with cocoyam had significant elevation ( P P P P >0.05) in the relative heart weights of all the rats in the three groups. The test feed contained considerable amounts of phenolics, crude fiber, Ca, Fe, K, Na but low amounts of oxalate and phytate. Conclusions C. esculenta may exert its anti-diabetic action by delaying/regulating the rate at which dietary starch is hydrolyzed to glucose or possibly through inhibition of acute pancreatitis. Finally, the study also shows the potentials of C. esculenta in the dietary management of obesity.

Management of Benign Prostatic Hyperplasia: Could Dietary Polyphenols Be an Alternative to Existing Therapies?

The incidence of benign prostatic hyperplasia (BPH) is gradually on the increase. While conventional drugs such as the α1-adrenergic receptor antagonists and 5α-reductase inhibitors have been found to be useful in the treatment of BPH, the adverse side effects associated with their usage, have led to increased search for alternative means of managing this disease. Furthermore, although surgery has also been suggested to be a sure method, the cost and risks associated with it excludes it as a routine treatment. Dietary polyphenols have gained public interest in recent times due to their roles in the prevention of various diseases that implicate free radicals/reactive oxygen species. However, their roles in the management of BPH have not been explored. Hence, this review on their prospects in the management of BPH and their mechanisms of action. Literature search was carried out in several electronic data bases such as PubMed, Google Scholar, Medline, Agora, and Hinari from1970 to 2017 to identify the current status of knowledge on this concept. The findings from these data bases suggest that while dietary polyphenols may not replace the need for the existing therapies in the management of BPH, they hold promise in BPH management which could be explored by researchers working in this field.

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

Abstract Context: The possibility of combining unripe plantain [Musa paradisiacae Linn (Plantaginaceae)] and cocoyam [Colocassia esculenta Linn (Araceae)] in the management of diabetes has not been investigated. Objective: The objective of this study is to evaluate the antihyperglycemic and antihyperlipidemic actions of unripe plantain and cocoyam. Materials and methods: Diabetes was induced in rats by intraperitoneal injection of streptozotocin (STZ) (65 mg/kg body weight). Twelve days after STZ induction, respective groups of diabetic rats were fed cocoyam (810 g/kg), unripe plantain (810 g/kg), and unripe plantain + cocoyam (405:405 g/kg) for 28 d. Body weights, feed intake, biochemical parameters, namely serum glucose, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), atherogenic index, coronary risk index, triacylglycerol, glycated hemoglobin (HbA1C), hepatic isocitrate dehydrogenase, malic enzyme, and glucose-6-phosphate dehydrogenase of the rats and phytochemical composition of the test and standard rat feeds were measured. Results and discussion: Cocoyam or unripe plantain alone significantly (p < 0.05) ameliorated the body weights (18.89 and 19.95% decreases, respectively) and biochemical parameters as compared with those of STZ controls (31.21% decrease). While combination of cocoyam and unripe plantain significantly (p < 0.05) ameliorated the biochemical parameters of the rats (except HbA1C), it did not ameliorate their body weights (28.53% decrease). The feed intake of the experimental rats did not differ from each other (p > 0.05) at the end of experimentation and the feed samples contained considerable amounts of saponins, alkaloids, flavonoids, and tannins. Conclusion: Cocoyam or unripe plantain alone showed better antihyperglycemic and anihyperlipidemic action than their combination.

Dietary intake of boiled breadfruit (Treculia africana) seeds did not improve hyperglycemia in streptozotocin induced diabetic rats: Effect on the oral glucose tolerance of normoglycemic rats

BACKGROUND Although African breadfruit (Treculia africana) is said to be useful in the dietary management of diabetes, the effect of cooking on its glycemic index has not been reported. Hence this study has investi- gated the effect of a dietary intake of boiled breadfruit on the serum glucose, glucose tolerance, body weights and relative organ weights of streptozotocin (STZ) induced diabetic rats. METHODS Twenty albino rats were used and were divided into four groups of five rats. Groups 1 (normal control) and 2 (diabetic control) received standard rat pellets while groups 3 (diabetic-test group) and 4 (non-diabetic) rats received breadfruit. RESULTS The blood glucose of the normoglycemic rats fed standard rat feeds peaked at 30 min (149.75 ±11.12 mg/dl) following oral glucose loading (3 g/kg) but reduced to 85.25 ±21.05 mg/dl after another 90 min, while the blood glucose of the normoglycemic rats fed breadfruit peaked at 30 min (146.25 ±15.22 mg/dl) follow- ing oral glucose loading, but elevated (130.75 ±36.69 mg/dl) after another 90 min. There was significant elevation (P < 0.05) of the serum glucose, relative liver weight (RLW) and relative kidney weight (RKW) but a significant decrease in the body weights of the diabetic control compared with the normal control; no sig- nificant difference (P > 0.05) in the serum glucose, body weights, RLW and RKW of the test group compared with the diabetic control, and no significant differences (P > 0.05) in the serum glucose, body weights, RLW and RKW of the normal rats fed the breadfruit diet compared to the normal control. CONCLUSIONS The study showed that the traditional method of cooking African breadfruit negatively affects its hypoglycemic property.