Clove (Syzygium aromaticum) and honey extracts significantly reduce inflammatory cytokines and liver function enzymes in experimental rats fed on carbon tetrachloride (CCl4)

Abstract

Liver is the key organ (detoxifier) that gets injured by reactive oxygen species (ROS) which deplete the body's stores of anti-oxidants. ROS is present in all chronic liver diseases leading to oxidative stress. Consumption of foods high in anti-oxidants replenishes and supplies the body with important anti-oxidants which break down ROS lowering inflammatory responses and preventing liver damage. In this work, clove and honey, which are known to be rich in anti-oxidants extracts were evaluated for their potential to breakdown ROS, Reactive nitrogen species (RNS) and lower oxidative stress in rats. Purified extracts were tested in vitro for ROS scavenging by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and in vivo using CCl4-induced liver injury model. A total of 50 experimental rats were assigned to 5 groups each consisting of 10 animals and treated as follows; 1. CCl4 group: fed on CCl4 in olive oil 2. honey group: fed CCl4 then honey extract, 3. clove group: CCl4 then clove extract, 4. double negative control group: rats fed on standard diet and 5 Negative control: fed olive oil, At 10 weeks, liver histopathology was done and sera collected for liver and kidney function tests. CCl4 -only treated rats showed fibroblastic cells proliferation and inflammatory cells infiltration which was absent in the control animals. Clove extract did not exhibit fibroblastic cells proliferation at all. Both clove and honey significantly reduced cytokines (TGF-β, TNF-α and EGF) and liver function enzymes'(ALT, AST and GGT) activity (58.5,56; 119,121 and 6.1; 6.3) compared to the CCl4 group (97; 191 and 10.1). Clove highly inhibited DPPH (77.2%) compared to honey (6.5%) and conferred better liver protection against CCl4. These findings indicate that clove and honey contain compounds that have anti-oxidant activity with the ability to reverse liver fibrosis. Frequent consumption of these foods may lower liver damage and prevent development of some liver diseases. Public health education on nutritional benefits of these foods is strongly encouraged. Keywords: Clove, Honey, Liver, CCl4, Antioxidant, ROS