Biochemical effect of Graviola against radiation-induced toxicity in experimental animals

The objectives of this study were to determine the radioprotective and antitumor effects of the aqueous extract of graviola leaves in the experimental animals. Graviola, the plant of Annonaceae family, is also known as annona muricata or soursop and its leaves are known as antioxidant and anticancer medicinal herbal and have gained biochemist attention because of their wide range of bioactivity. The radioprotective effect of graviola was investigated against γ-irradiation (IRR)-induced toxicity in male albino rats. Rats exposed to ionizing radiation (IR) exhibited a potential elevation of hepatic and cardiac serum enzymes, lipid profile and heme oxygenase activity (HO-1). The γ-irradiation group also resulted in significant increase in tissue lipid peroxidation, total nitrate/nitrite NO(x), marked DNA fragmentation and caspase-3 activation as well as reduced glutathione (GSH) content, superoxide dismutase (SOD), adenosine triphosphate (ATP) level and glutathione peroxidase gene expression (GPx mRNA) were significantly decreased in hepatic and cardiac tissues. Administration of graviola (100 mg/kg B.W.) for 14 days prior to IRR ameliorated the hepatotoxicity and cardiotoxicity induced by IRR. Histopathological examination of liver and heart tissues confirmed the biochemical data. Also the antitumor activity of graviola and/or irradiation was evaluated against Ehrlich Ascites Carcinoma (EAC) and Solid Ehrlich Carcinoma (SEC) in female mice. The intraperitoneal (I.P.) injection once with graviola (100 mg/kg B.W.) showed significant delay in the tumor volume of mice-bearing SEC. In the EAC-bearing mice graviola showed a marked delay in the increase of body weight and significant increase in mean survival time (MST) and percent change in life span (%CLS) compared to untreated control group. Irradiation of mice-bearing SEC with single dose of 6 Gy resulted in significant reduction in the tumor volume. Irradiation of mice-bearing EAC demonstrated an obvious decrease in the average body weight and non-significant increase in MST and %CLS compared to untreated control group. The combination between graviola and γ-irradiation confirmed better results in the preceeding parameters compared to untreated control group or γ-irradiated group alone. Furthermore, our investigations on the graviola leaf extract showed a potent free radical scavenging activity and exhibited antitumor effect against both of Ehrlich ascites carcinoma and Ehrlich solid carcinoma