The Effects of Bitter Kola Supplemented Diet on Hepatotoxicity of Mercury in Wistar Rats

The effect of bitter kola on the hepatotoxicity following mercury poisoning (mercuric chloride solution of 10ppm) was investigated in rats for a duration of six weeks. Thirty (30) acclimatized Wistar rats were divided into five groups(n=6).Group I served as control and were fed on normal rat chow and clean water ad libitum, group II received normal chow and mercury contaminated water (10ppm), group III animals were given clean water and 5% w/w bitter kola supplemented rat chow, group IV rats received bitter kola supplemented rat chow and mercury contaminated water, group V animals were placed for the first week of the experiment on mercury contaminated water and normal rat chow before substituting with clean water and bitter kola supplemented rat chow. Two (2) animals from each group were sacrificed at the end of 2, 4 and 6 week and blood collected by cardiac puncture before the liver was harvested .Serum Alkaline phosphatase (ALP), Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT) and hepatic content of Mercury (Hg) were determined by standard laboratory methods. The results (Mean ± SEM) showed that G kola supplemented diet significantly lowered the hepatic mercury content as well as limited the hepatotoxic effects of the heavy metal indirectly assessed by measurement of the serum levels of alkaline phosphatase and the transaminases. @ JASEM The element, mercury is considered a global pollutant (Fitzgerald et al, 1998; Jackson, 1997). Although exposure to mercury from therapeutics is now uncommon, occupational and environmental exposure continue to pose potentially serious treat to the living and unborn human populations (Klaasen,1999).Poisoning from environmental sources usually arise from contaminated drinking water as well as plant and animal sourced food products. The metal has been reported to be highly prone to bioaccumulate, leading to biomagnification along the food chain (EPA,1997). The absorption, distribution, metabolism, excretion and toxicodynamics of mercury have been reported to depend on the form and oxidation states (ATSDR, 1989). The forms of mercury important from a toxicological point of view are elemental (vapor), inorganic salts and organic salts of mercury. Ingestion of inorganic mercury salts such as mercuric chloride have been reported to cause mainly severe gastrointestinal irritation and renal failure (Klaasen,1999).The toxic effects of organic and elemental mercury have also been widely reported(Wikipedia,2009).Several epidemiologic studies had been conducted on the exposure of humans to mercury through fish and marine mammal consumption in different geographical areas (Bakir et al,1973).And about 25 food related compounds, including cysteine, fish protein, garlic, gluthation, r-Linolenic acid, phospholipids, and others have been reported to alter the metabolism of mercury.(Chapman and Chan,2000).Selenium ,Vitamin C and E as well as other essential minerals have been claimed to be effective against mercury toxicity in animal studies (Chowdhury and Chandra,1987; Watanabe,2002) . On the contrary, mega doses of vitamin B12 with or without folic acid or folic acid alone have been reported to increase methyl mercury concentration in the liver of guinea pigs administered mercuric chloride subcutaneously(Zorn and Smith,1990).The liver is recognized as one of the soft tissues or organs that ingested mercury especially the organic mercurials distribute to leading to increased hepatic content (Klaasen 1999).Hepatic Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT) and Alkaline Phosphatase have been reported to increase in domesticated rabbits that were treated with mercurous chloride salt (Anjum and Shakoori, 1994). In another study conducted on teleost fish exposed to LC50 (1.8 mg/L and sublethal (0.3mg/L) concentrations of mercuric chloride, it was also observed that GPT and GOT blood levels were elevated by 96hr for lethal exposure while for sublethal exposure resulted in elevated enzyme levels by the 15 and 30 day: Alkaline phosphatase level also increased following chronic exposure (Sastry and Sharma, 2000). Garcinia kola (Syn Bitter kola) belongs to the Crusiaceace family. It is native to Asia, South Africa and Polynesia, it is also found in West and Central Africa.The genus has about 50 species of ever green trees and shrubs. The seed is chewed as masticatory, stimulant and for its bitter taste in traditional hospitality cultural and social ceremonies (Olaleye et al, 2000). The plant has also been reported to possess anti-ulcerogenic and gastric acid lowering effects (Okunji and Iwu,1991; Ibironke et al,1997); anti-fungal effects (Olojede et The Effects of Bitter Kola Supplemented Diet on Hepatotoxicity of Mercury in Wistar ................... * Corresponding author: Ejebe D.E. 90 al,1993); antiviral, anti diabetic(Iwu,1986) and anti hepatotoxic activities (Akintowa and Essien,1990; Farombi et al,2000). Given the possibility that some persons exposed to mercury may indulge in any of the different uses of bitter kola, there is need to evaluate the possible effects of this nutritional factor on the toxicokinetic and toxicodynamics of mercury. This study is an investigation into the effects of bitter kola supplemented diet on mercury induced hepatotoxicity in Wistar rats.