In Vivo and In Vitro Studies on the Antioxidant Activity of Sea Cucumber Aqueous Extract against Isoproterenol-Induced Myocardial Injury in a Rat Model

Abstract

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 β-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 contrast reduced serum low density lipoprotein-cholesterol 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&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.

Keywords: Holothuria atra extract, HPLC analysis, Isoproterenol, Biochemical studies, In vitro antioxidant studies, Histological studies