In vivo and in vitro studies on the antioxidant activity of sea cucumber aqueous extract against isoproterenol-induced myocardial injury in a rat model

The present study was undertaken to evaluate the cardiopreventive activity of the aqueous extract of sea cucumber body wall against isoproterenol-induced cardiac injury in rats. Isoproterenol a synthetic catecholamine and beta-adrenergic agonist, which causes severe oxidative stress-induced myocardial injury. HPLC analysis of the sea cucumber aqueous extract revealed the presence of some active phenolic components with antioxidant activity, such as pyrogallol, rutin, chlorogenic acid, ascorbic acid, catechin, coumaric acid, cinnamic acid, and ellagic acid. Subchronic oral administration of sea cucumber extract [14.4mg/Kg b.w.] to normal rats thrice weekly for 8 consecutive weeks did not exert any toxic side effects. whereas enhanced the cardiac reduced glutathione level and catalase activity, and in contract reduced serum low density liporprotein-cholestrol level. On the other hand, pretreatment of rats with the sea cucumber extract for 8 weeks before being intoxicated with 2 subcutaneous injections of isoproterenol normalized serum levels of total CK, CK-MB activity, total cholesterol. triglycerides and high-density lipoprotein-cholesterol, as well as cardiac glutathione peroxidase and catalase activities. In vitro antioxidant studies on the sea cucumber extract have shown a moderate scavenging activity for NO radical and iron chelating activity, as well as a weak inhibition of lipid peroxidation. In addition, histopathological examination of H and E stained myocardium sections of the left ventricle showed that pretreatment of isoproterenol-intoxicated rats with sea cucumber extract caused a substantial attenuation in the degenerative cellular changes induced by isoproterenol

Cardioprotective activity of polysaccharopeptides extracted from pleurotus ostreatus mycelium in a doxorubicin-rat model

The present study was undertaken to investigate the possible abatement of doxorubicin-induced cardiomyopathy in the rat by polysaccharopeptides extracted from the culture broth of Pleurotus ostreatus mycelium. It was found that polysaccharopeptides given as protection before doxorubicin intoxication normalized the levels of serum total creatine kinase, aspartate aminotransferase and lactate dehydrogenase activities, in addition to malondialdehyde, reduced glutathione, as well as superoxide dismutase and catalase activities in the heart tissue. Nitric oxide and tumor necrosis factor-alpha concentrations were persistently reduced in the heart tissue, while interferon-gamma concentration was insignificantly changed, compared to controls. Light microscopic examination of haematoxylin and eosin-stained sections of the left ventricles showed normal structure of the cardiac myocytes, except for a slight but significant decrease in their thickness, compared to controls. Pretreatment with mycelial polysaccharopeptides provided a potential protective effect against doxorubicin-induced oxidative stress in rats

Resveratrol, a natural phytoalexin: a therapeutic promise for metabolic disorders in streptozotocin-nicotinamide induced type 2 diabetic rats

Resveratrol, a natural phytoalexin, has demonstrated a wide variety of biological activities, which make it a good candidate for treatment of diabetes mellitus. The present study was aimed to evaluate the properties of resveratrol [RSV] as an antidiabetic agent in streptozotocin-nicotinamide [STZ-NIC] induced Type2 diabetes model. Furthermore, the antidiabetic nature of resveratrol was compared with glyclazide, an oral standard antidiabetic drug. This study includes 40 male albino rats divided into 5 groups: control, control+resveratrol, diabetic, diabetic+resveratrol and diabetic+ glyclazide. The antidiabetic effect of oral administration of RSV [5mg kg/b.wt] for 45days was evidenced from the improvement in the levels of blood glucose, glycosylated hemoglobin and the calculated homeostasis model assessment of insulin resistance. The significant decrease [p<0.05] in plasma insulin level exhibited in the diabetic rats was not affected by RSV treatment, indicating that the hypoglycemic effect of RSV is independent of insulin. The altered activities of key enzymes of carbohydrate metabolism such as glucokinase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase and glycogen synthase in liver tissues of diabetic rats were all significantly reverted [p<0.05] to near normal levels by administration of RSV. Hyperlipidemia observed in the diabetic group of rats was markedly alleviated by oral treatment with RSV. Lastly, STZ-NIC induced diabetic rats orally treated with RSV had significantly lower [p<0.05] plasma homocystein level and significantly higher [p<0.05] serum folic acid and vit. B12 levels than the untreated ones indicating improvement in the endothelial function in those rats. The present study suggests that STZ-NIC induced diabetes is an excellent model for type2 diabetes, and that RSV is an effective therapeutic agent for treatment of type 2 diabetes mellitus