Biological activities of the crude skin toxin of the Suez Gulf oriental catfish (Plotosus lineatus) and its antitumor effect in vivo (mice)

Quantitative determination of newly reported enzymes activity in the crude skin toxin (CST) of catfish revealed highest activities of hyaluronidase and lipase, lesser activities of phospholipase A2, lactate dehydrogenase (LDH), cholinesterase (CE), alkaline phosphatase (ALP), and aspartate transaminase (AST), and least activities of proteinase and 5-nucleotidase (5'-NT). The CST has a hemolytic activity of 54% and no ichthyotoxicity up to 500 ug/ml. The chosen dose of CST (LD12.5) showed a potential cytotoxic activity against solid Ehrlich carcinoma-bearing mice demonstrated by an increase in the mean survival time (238.8%) and tumor growth inhibition ratio (T/C) of 73%. The CST ameliorated the relative weights of heart and liver after three weeks, while modulating the elevation in the relative spleen weight throughout the treatment periods (three, six, and nine weeks). The levels of serum triglyceride, total cholesterol, and liver total lipids were normalized after three weeks, whereas the serum albumin and hepatic glycogen concentrations, as well as ALT, AST, 5'-NT, and G-6-Pase activities were ameliorated after 6 weeks. Serum levels of glucose, LDH, and creatine kinase (CK) activities were significantly modulated throughout the treatment periods. Histological examinations of the tumor and liver tissues of treated tumor-bearing animals were carried out. Tumor tissues showed many cytolytic and cytopathic changes after treatment, while liver tissues showed moderate dysplastic changes after six weeks of treatment, which became more marked after nine weeks.