title: The chemopreventive effect of Ginkgo biloba and Silybum marianum extracts on hepatocarcinogenesis in rats.
abstract: OBJECTIVE
  This study was designed to evaluate the potential chemopreventive activities of Ginkgo biloba extract (EGb) and Silybum marianum extract (silymarin) against hepatocarcinogenesis induced by N-nitrosodiethylamine (NDEA) in rats.
  
  
  METHODS
  Rats were divided into 6 groups. Group 1 served as normal control rats. Group 2 animals were intragastrically administrated NDEA at a dose of 10 mg/kg five times a week for 12 weeks to induce hepatocellular carcinoma (HCC). Groups 3 and 4 animals were pretreated with silymarin and EGb respectively. Groups 5 and 6 animals were posttreated with silymarin and EGb respectively. The investigated parameters in serum are alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyltransferase (GGT) and vascular endothelial growth factor (VEGF). The investigated parameters in liver tissue are malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and comet assay parameters.
  
  
  RESULTS
  In NDEA group, MDA level was elevated with subsequent decrease in GSH level and SOD, GPx and GR activities. In addition, NDEA group revealed a significant increase in serum ALT, AST and GGT activities and VEGF level. Furthermore, NDEA administrated animals showed a marked increase in comet assay parameters. These biochemical alterations induced by NDEA were confirmed by the histopathological examination of rat livers intoxicated with NDEA that showed an obvious cellular damage and well differentiated HCC.In contrast, silymarin+NDEA treated groups (3&5) and EGb+NDEA treated groups (4&6) showed a significant decrease in MDA level and a significant increase in GSH content and SOD, GPx and GR activities compared to NDEA group. Silymarin and EGb also beneficially down-regulated the increase in serum ALT, AST, GGT activities and VEGF level induced by NDEA. In addition, silymarin and EGb significantly decreased comet assay parameters. Histopathological examination of rat livers treated with either silymarin or EGb exhibited an improvement in the liver architecture compared to NDEA group.
  
  
  CONCLUSIONS
  The obtained findings suggested that silymarin and EGb may have beneficial chemopreventive roles against hepatocarcinogenesis through their antioxidant, antiangiogenic and antigenotoxic activities.
authors: Therapeutical Chemistry Department, Pharmaceutical and Drug Industries Research Division, National Research Centre (NRC), Tahrir st,, Dokki, Giza, Egypt. nadiametwally@yahoo.com.
authors: Hala O
authors: HO
authors: El Mesallamy
authors: Nadia S
authors: NS
authors: Metwally
authors: Mahmoud S
authors: MS
authors: Soliman
authors: Kawkab A
authors: KA
authors: Ahmed
authors: Mai M
authors: MM
authors: Abdel Moaty