The Role of Silymarin in the Protection of Mice Liver Damage Against Microcystin-LR Toxicity

The presence of cyanobacterial toxins in drinking and recreational waters represents a potential risk to public health. Microcystin-LR (MC-LR) is a potent cyclic heptapeptide hepatotoxin produced by the blue-green algae Microcystis aeruginosa (M. aeruginosa). Chemoprotectant studies suggest that membrane-active antioxidants may offer a protection against microcystin toxicity. The aim of this study is to investigate the potential benefits of dietary supplementation of silymarin as antioxidant on microcystin toxicity in mouse livers. A group of Balb/c mice was pre-treated for ten days with silymarin (extracted from milk thistle seeds collected from local areas of north Jordan) (400 mg of silymarin /Kg mouse body weight given orally once a day for 10 days), before an intraperitoneal injection (i.p) with 200 |jg toxin/kg mouse body weight of MC-LR (according to LD50 value). Pre-treatment of mice with a single dose of silymarin, aflavonolignane (Silybum marianum L. Geartin) completely abolished the lethal effects and significantly decreased the levels of serum enzymes, alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and gamma glutamyl transferase (GGT), inhibition of Protein phosphatase (PP1) , level of methylglyoxal (MG) and lipid peroxidation (LPO) as MDA amount induced by MC-LR. Therefore, silymarin supplied as dietary supplement may have protective effects against chronic exposure to MC-LR.