Potential antioxidant effect of essential oil of Ocinum basilicum in liver of Dicentrarchus labrax

The increasing problems associated with infectious diseases in farmed fish represent major challenges for this source of food production. As the use of antibiotics in aquatic environment poses serious problems at the level of environmental impact and to human health, research on antimicrobial agents from natural sources has received much attention. In addition some naturally occurring antimicrobial agents can be formulated as functional foods and nutraceuticals that can also help to prevent oxidative damage from occurring in the body. The phytochemical preparations with dual functionalities in preventing lipid oxidation and antimicrobial properties have remarkable potential for extending shelf life of food products. As regarding the genus Ocinum, namely Ocinum basilicum, in vitro results are reported on both the antioxidant and antimicrobial activity of its essential oil. In the present communication, an attempt has been made to explore in vivo the possible antioxidant properties of essential oil of O. basilicum in sea bass Dicentrarchus labrax, a widely utilized species in aquaculture, infected with Vibrio alginolyticus. The results obtained show that hepatic lipid peroxidation (measured as TBARS production) induced in D. labrax following infection with V. alginolyticus, is reduced in fish fed with O. basilicum essential oil. In the liver of the same fishes, antioxidant enzymatic activity of glutathione S-transferase (GST) and catalase, is also increased. In light of the results obtained, we suggest that the protective effect of O. basilicum essential oil could be due to activation of the cellular antioxidant system. Further studies are in progress to define the mechanism by which essential oil of O. basilicum could affect the synthesis or regulation of antioxidant enzymes