Hepatoprotective and antioxidant effects of porcine plasma protein hydrolysates on carbon tetrachloride-induced liver damage in rats.

Porcine plasma protein hydrolysate (PPH) prepared by alcalase for 5 h was fractioned by ultrafiltration. Four fractions, H(1) (MW>10k), H(2) (MW 6-10k), H(3) (MW 3-6k) and H(4) (MW<3k), were obtained. H(4) possessed the highest antioxidant activity as indicated by thiobarbituric acid-reactive substance values and hydroxyl radical scavenging activity (P<0.01). Male rats were pretreated with H(4) at dose of 50, 100, and 200 mg/kg of body weight orally once daily for 12 days, then they were treated intraperitoneally with a single dose of CCl(4) (2 mL/kg of body weight). The results showed that oral feeding of H(4) could significantly lower (P<0.01) the serum levels of hepatic enzyme markers (aspartate transaminase and alanine transaminase). Compared with the CCl(4)-only treatment group, levels of hepatic superoxide dismutase, glutathione peroxidase, catalase and total antioxidant capacity were significantly increased, and the malondialdehyde levels were sharply decreased (P<0.01) in rats treated by all doses of PPH fraction H(4). A histological examination of the liver showed that lesions, including necrosis, lymphocyte infiltration and fatty degeneration, were partially healed by treatment with H(4) fractions. These data suggest that in rats, PPH can protect the liver against CCl(4)-induced oxidative damage.