​Local spices ‘cure’ for crude oil products-induced toxicity.

Guardian. Lagos. Nigeria. 1.11.12

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Petroleum products have been shown to be toxic to the liver and can cause cancers. But two local spices may be the antidote or could be used to ameliorate the effect of petroleum products on human health. CHUKWUMA MUANYA writes.
NIGERIAN researchers have demonstrated how regular intake of local spices/vegetables, Gongronema latifolium and Ocimum gratissimum, could be used to ameliorate or prevent the damage caused by petroleum products on human health such as liver damage and cancers.
Gongronema latifolium is commonly called Utazi in Ibo and Arokeke in Yoruba. It belongs to the family Asclepiadaceae and it is a tropical rain forest plant primarily used as spice and vegetable in traditional folk medicine.
Commonly called Scent leaf, Ocimum gratissimum is a herbaceous plant which belongs to the Labiatae family. It is cultivated in rainforest and savannah areas of Nigeria. In Nigeria it is called Nchanwu in Ibo, Effinrin-nla in Yoruba, and Daidoya in Hausa.
The researchers from the Department of Biochemistry, Federal University of Technology, Owerri, Imo State; and Department of Biochemistry, University of Nigeria, Nsukka, Enugu State concluded: “This study has shown that diesel induced toxicity can be ameliorated by the consumption of Gongronema latifolium and Ocimum gratissimum, two abundant spices in Nigeria. We recommend increase usage and consumption especially in the Niger Delta region of Nigerian where the population is constantly exposed to petroleum product contamination.”
The study titled “Biochemical Studies on the Amelioration of Petroleum Product Intoxication with Indigenous Plants” was published recently in International Journal of Biochemistry Research & Review.
The researchers investigated the effect of Gongronema latifolium and Ocimum gratissimum supplemented diet on diesel petroleum induced liver damage in rats. Rats were acclimatized for two weeks and divided into three groups. Oxidative stress was induced with diesel petroleum (4 ml/kg body weight) at alternate days for seven days in group II and III rats.
Group II rats were fed the supplemented diet while Group I and III fed on normal rat pellet only. After one week of feeding, the fluctuations in the activities of antioxidant enzymes - superoxide dismutase and glutathione peroxidase and concentrations of glutathione and malondialdehyde (MDA) indicated stress in the liver of the rats exposed to diesel.
Significant increase in serum concentration of Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) and other liver damage markers was observed in group III rats. Serum lipid profile was also studied.
Feeding with the supplemented diet showed significant reduction in the activities of ALT and AST and in the concentration of MDA. The activities of some antioxidant enzymes indicated non- significant increase with treatment. The concentration of other liver marker compounds and lipid profile were positively affected by the treatment.
The values obtained from treated rats showed that, while diesel can induce oxidative damage to the liver, G. latifolium and O. gratissimum in the diet, indicated protective effect against oxidative and cellular degeneration in liver tissues.
Gongronema latifolium and Ocmium gratissimum are commonly consumed spices in Nigeria, which have useful medicinal potential. They have been shown to have high level of phytochemicals and also posses’ antibacterial, antitumor, anticancer and antidiabetic properties.
Phytochemical analysis indicates that G. latifolium is nutritionally high in iron, zinc, vitamins, protein and amino acids. The leaf extracts contains alkaloids, saponins, tannins, flavonoids and glycosides. The anti-oxidative properties have been utilized in the management of diabetes mellitus and other tropical diseases.
Phytochemical analysis shows that O. gratissimum is rich in alkaloid, tannin, phytate, flavonoids and oligosaccharides and tolerable cyanogenic content. Previous studies found that the leaves can be used to treat diarrhea, stomach upset and haemorrhoids. O. gratissimum is commonly used in Nigeria to treat upper respiratory tract infections, diarrhoea, headache, diseases of the eye, skin diseases, pneumonia, cough, fever and conjunctivitis. Most Nigerians, especially those in Niger Delta region use the leaves of these plants combined in the preparation of soups and stews and in herbal concoctions.
The researchers wrote: “The liver maintains and regulates homeostasis in living systems. It is involved in some biochemical pathways, which are necessary for growth and fight against diseases. It also supplies nutrients and energy. Therefore, maintenance of a healthy liver is essential for the overall well being of an individual. In xenobiotic induced hepatotoxicity, the balance between reactive oxygen species (ROS) production and antioxidants is lost. This could result in oxidative stress, a consequence of series of biochemical events which deregulate cellular functions leading to hepatic necrosis.
“In this study, the reduced activities of superoxide dismutase and glutathione peroxidase and increase concentration of MDA in rats intoxicated with diesel petroleum but not fed with supplement diets indicates hepatic oxidative damage. This observation is similar to that in rats administered with Carbon tetrachloride (CCl4), which is used to induce liver damage.
“Catalase, found in nearly all living organisms are involved in the reduction of reactive oxygen species and protects the cell from oxidative stress. Decreased activity of catalase in untreated animals exposed to diesel petroleum could be due to its involvement in antioxidative activities. Superoxide dismutase (SOD) catalyses the conversion of naturally occurring but harmful superoxide radicals into molecular oxygen and hydrogen. The observed decrease in SOD activity could be a consequence of its oxidation by free radicals.
“Reduced activity of SOD could lead to immune system damage. Treatment of rats with supplemented diet indicated a non significant increase in activities of catalase and SOD when compared with untreated rats. These variations in activities suggest a potential antioxidative ability of G. latifolium and O. gratissimum supplemented diet on prolonged usage.
“The activities of Glutathione peroxidase (GPx) protect organisms from oxidative damage. The decreased activity of GPx as seen in untreated group may indicate its use in the reduction of hydrogen peroxide to water. Reduced activities of GPx are associated with oxidative DNA damage and as a result lead to risk of cancer. Feeding on the supplemented diet showed a non significant increase in GPx activities when compared with untreated rats.
“Glutathione (GSH) is an important antioxidant produced by liver cells and the major soluble antioxidant in cell compartment. The significant decrease in GSH concentration may be attributed to its use in various protective roles against oxidants. Treatment with supplemented diet of O. gratissimum and G. latifolium resulted in non significant change in the concentration of GSH. Malondialdehyde concentrations increased significantly, indicating the amount of cellular damage. This increase could signify damage, from lipid peroxidation.
“Rats treated with O. gratissimum and G. latifolium showed reduction in MDA concentration, suggesting possible antioxidative role of these spices.
“The values obtained for AST and ALT corroborates the results from oxidative stress parameters in which some (glutathione and MDA) indicated diesel induced oxidative stress in the animals. The serum activities of AST and ALT increased significantly in untreated rats indicating liver injury and leakage of enzymes into blood. This is in agreement with the findings of (Patrick-lwuanyawu et al., 2011) in their study on the hepatotoxic and nephrotoxic effect of kerosene and petrol contaminated diets in Wistar albino rats.
“Activities of ALT rises in diseases associated with death of hepatocytes, like viral hepatitis. AST on the other hand is not specific for liver damages but has been found to be a cardiac marker as it is found in cardiac and skeletal muscles. The activities of AST and ALT in treated rats were significantly lower when compared to untreated rats. The dysfunctional liver also affected protein metabolism. The concentration of serum proteins (albumin, globulin) decreased in the untreated group when compared to control and treated rats.
“Similar observations were made by (Nwaogu and Onyeze, 2010) when they studied the effect of spent engine oils on oxidative stress parameter. The treated animals showed a non-significant increase in concentration of albumin, a protein made specifically by the liver. Study has shown that it reduces in chronic kidney damage where it is lost through urine. The significant decrease in globulin concentration indicates liver damage and also suggests a problem in the immune system because globulin is produced in the liver with some percentage by the immune system. Higher concentrations of these proteins were observed in treated group when compared with untreated group, suggesting a hepato-protection by O. gratissimum and G. latifolium supplemented diet.
“The values obtained in the lipid profile shows a non significant increase in the concentration of cholesterol and a significant increase in Low Density Lipo-protein (LDL)- ‘bad’ cholesterol in untreated group. Increase in serum cholesterol emphasizes liver dysfunction, as cholesterol is synthesized in the liver and also excreted by the liver. The increase in the concentration of LDL-cholesterol is probably because of increased concentration of cholesterol. LDL-cholesterol can be deposited on the walls of the artery leading to arthrosclerosis and other cardiovascular diseases. High concentration of cholesterol in the serum could lead to diseases like arthrosclerosis and stroke (Brown, 2007).
“Also high serum cholesterol has been reported to decrease concentration of circulating insulin and serum glutathione. These metabolic alterations predispose hepatocytes to lipid peroxidation as observed in the increased concentration of MDA in rats as a result of diesel intoxication. The concentration of triglyceride, High Density Lipo-protein (HDL)- ‘good’ cholesterol and Very Low Density Lipo-protein (VLDL)- cholesterol was significantly lower in untreated animals. These lipids are synthesized by liver cells. Hence their lower concentration signifies liver dysfunction, resulting in the inability of liver to properly package the lipids.
“HDL-cholesterol has higher molecular weight than other lipoproteins and transports cholesterol from the arterial walls back to the liver where it is used for biosynthesis. Therefore, its decrease in untreated group signifies increased chances of arthrosclerosis and vascular diseases. However, the concentrations of cholesterol and LDL-cholesterol in the treated rats were lower when compared to those of the untreated, indicating hypo-lipidemic action and the ability of the contents of the supplements to improve lipid metabolism in hepatocytes. The concentration of HDL-cholesterol was higher in treated group signifying a better state of the liver and better cardiovascular health. High HDL-cholesterol concentration favours cholesterol clearance from the arteries. The values obtained in the treated group shows that O. gratissimum and G. latifolium can be used in improving the cardiovascular health.”