Attenuation of expression of cytokines, oxidative stress and inflammation by hepatoprotective phenolic acids from Thespesia populnea Soland ex Correa stem bark

Recently a highly active hepatoprotective phenolic acids fraction (PF) has been isolated from Thespesia populnea stem bark. This fraction showed hepatoprotective action against toxic chemicals such as carbon tetrachloride, acetaminophen and thioacetamide. It also showed in vitro anti-Hepatis B viral activity in cultured cells. In the present study, follow up investigations were carried out to determine the effect of PF on the expression of TNF-alpha, IL-6 and IL-10 in acetaminophen challenged rats. Further, the anti-inflammatory and in vitro antioxidant activities of PF were assessed. Acetaminophen administration resulted in liver damage and elevated levels of TNFalpha, IL-6 and IL-10. PF (2 mg/kg) administration prevented, to a large extent, acetaminophen-induced increase in the levels of these cytokines and liver injury. PF administration attenuated carrageenan induced paw edema in mice and rats. It showed potent in vitro antioxidant activity. Thus, the present study shows for the first time that PF from T. populnea attenuates toxic chemical-induced up-regulation of the cytokines and possesses antioxidant and anti-inflammatory properties. PF did not exhibit any conspicuous toxic symptoms in the preliminary subacute toxicity evaluation in rats. Therefore, PF is very promising for drug development.