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How bitter leaf prevents kidney, liver, heart damage


Can regular intake of biter leaf protect the vital organs from damage due to toxicity from poisonous substances?

Nigerian scientists have demonstrated how bitter leaf could be used to prevent kidney, liver and heart damage.

Botanically called Vernonia amygdalina, bitter leaf is of the plant family Compositae. It is called ewuro in Yoruba and onugbu in Ibo. It is a small shrub that grows predominantly in the tropical Africa. In Nigeria, the plant is locally called bitter leaf due to its bitter taste.

A study published in the Journal of Food and Nutrition Sciences demonstrated that ethanol leaf extract of Vernonia amygdalina ameliorate and protect liver, kidney and heart of male albino Wistar rats against theobromine induced toxicity and modulates the adverse effects on lipid profile.

Theobromine is the primary bitter-tasting alkaloid found in cocoa and chocolate. It has been reported to be toxic with oral average Lethal Dose (LD50) in the range of 950 mg/kg and 1356 mg/kg body weight in rats and mice, respectively. Eteng et al. reported that theobromine induces cardiotoxicity in experimental animals, which was evident in increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum. Histological evaluation of the heart of the experimental animals further proved that theobromine induces damage to the heart.


Adeyina et al. also carried out studies on the comparative effect of theobromine and cocoa bean shell (CBS) extract on serum enzyme activities in rabbits. Increase in the value of serum alkaline phosphate (ALP) and AST activities in rabbits administered theobromine was reported. The increase in ALP and AST was attributed to theobromine toxicity affecting the liver with subsequent breakdown in membrane architecture of the cells leading to spillage of the enzymes into the serum.

The researchers concluded: “The present study has demonstrated that ethanol leaf extract of Vernonia amygdalina protects the liver and heart of male albino wistar rats against theobromine induced toxicity as evidenced by its ability to reverse elevated activities of serum enzymes (ALT, AST and ALP). The extract also protects against kidney damage by restoring to normal values the theobromine induced increase in the serum concentrations of urea and creatinine.

“Dyslipidemia caused by the treatment of the experimental animals with theobromine was modulated by the ethanol leaf extract of Vernonia amygdalina. Additionally, the theobromine induced alterations in the histology of the liver, heart and kidney sections of the experimental rats were normalized following treatment with ethanol leaf extract of Vernonia amygdalina.”

The study is titled “Effect of Ethanol Leaf Extract of Vernonia amygdalina on Some Indices of Liver, Kidney Function and Lipid Profile in Theobromine Intoxicated Male Albino Wistar Rats.”

The researchers are from the Department of Biochemistry, Faculty of Basic Medical Sciences, University of Uyo, and Department of Biochemistry, Faculty of Natural and Applied Sciences, Obong University, Etim Ekpo, Akwa Ibom State.

The researchers investigated the effect of ethanol leaf extract of Vernonia amygdalina on some indices of liver, kidney function and lipid profile in male albino Wistar rats intoxicated with theobromine.

Thirty male Wistar rats weighing between 140gramme – 160 gramme used for the study were divided into six groups with five animals in each group. Group I served as control while Group 2 received 700 mg/kg body weight (bw) of theobromine daily for four days. Group 3 received 400 mg/kg bw of V. amygdalina leaf extract daily for 21 days while Groups 4 and 5 were treated with 400 mg/kg bw of V. amygdalina leaf extract for 21 days before and after intoxication with 700 mg/kg bw of theobromine for four days respectively. Group 6 was given 700 mg/kg bw of theobromine daily for four days and then allowed for 21 days without treatment. Serum was obtained from whole blood and used to determine activities of some serum enzymes and lipid profile as well as kidney function. The liver, kidney and heart were excised and used for histological studies.

The results show significantly increased serum enzyme activities, total cholesterol and Low Density Lipo-protein (LDL)/bad cholesterol concentration in Group 2 compared to the control. High Density Lipo-protein (HDL)/good cholesterol was significantly decreased in theobromine treated group when compared to Group 1. Administration of V. amygdalina leaf extract alone showed results close to those of the control. Group 4 showed decreased serum enzyme activities, decreased concentration of total cholesterol and LDL cholesterol while HDL cholesterol was increased significantly when compared to Group 2. Group 5 also showed a significant difference in the biochemical indices when compared to Group 2 while Group 6 show decreased serum enzyme activity that was significant when compared to Group 2.

The urea and creatinine concentrations were significantly increased in theobromine intoxicated animals while administration of Vernonia amygdalina normalised these parameters. Histology of the liver, kidney and heart revealed altered cellular architecture following administration of theobromine (Group 2) while normal histological features were restored after treatment with ethanol leaf extract of V. amygdalina.

Also, researchers from the Department of Biochemistry, Delta State University, Abraka, concluded: “This study indicated that the consumption of crude petroleum contaminated diets induced kidney damage and consequent malfunction. However, the administration of bitter leaf extract offered defence against the induced negative effects of crude petroleum and ameliorated and restored the lost renal function capabilities by conferring protection on tissue ultra-structure.”

The study, published in International Journal of Veterinary Science and Medicine, is titled “Role of bitter leaf (Vernonia amygdalina) extract in prevention of renal toxicity induced by crude petroleum contaminated diets in rats.”

The efficacy of Vernonia amygdalina against chemical toxicity has attracted attention. The aim of the study was to evaluate the protective potentials of Vernonia amygdalina methanol extract (BLME) against petroleum toxicity. Thirty six male albino rats (Rattus norvegicus) were redistributed randomly into six groups of six rats each and fed with growers feed for a period of 30 days according to the following description: Group A = Feed; Group B = Feed + 100 mg kg−1 body weight of BLME; Group C = Feed + 200 mg kg−1 body weight of BLME; Group D = Feed (100 g Feed + 4 mL crude petroleum); Group E = Feed (100 g Feed + 4 mL crude petroleum) + 100 mg kg−1 body weight of BLME; Group F = Feed (100 g Feed + 4 mL crude petroleum) + 200 mg kg−1 body weight of BLME.

Animals were sacrificed at the end of the experimental period and the serum and kidney were harvested for biochemical and histological analysis following standard procedures. The data generated were subjected to analysis of variance (ANOVA).

The study revealed that crude petroleum stimulated alterations in kidney dysfunction makers: urea, creatinine and serum electrolytes, which were significantly ameliorated by BLME administration relative to control. Oxidative stress markers, lipid peroxidation and enzymatic and non-enzymatic antioxidant profiles (MDA levels, GSH, Vitamin C. FRAP, CAT, SOD, GPx, GSTs) as well as oxidase enzymes (AO, SO, MO and XO) induced changes by crude petroleum were positively modulated by BLME administration.

The study concluded that crude petroleum contaminated diets are injurious to animal health and BLME is able to prevent the renal dysfunction induced by crude petroleum contaminated diets.

Until now, the leaf of Vernonia amygdalina is widely consumed as vegetable for its rich array of nutritional components and phytochemicals which are responsible for the various health and medicinal benefits attributed to Vernonia amygdalina. The proximate composition of Vernonia amygdalina has revealed significant quantities of lipids, proteins with high essential amino acid score that compare favourably with values reported for Telfairia occidentalis (fluted pumpkin/ugu) and Talinum triangulare (green vegetable), carbohydrates and fibre. The plant has also been shown to contain appreciable quantities of ascorbic acid, carotenoids, calcium, iron, potassium, phosphorous, manganese, copper and cobalt.


The presence of oxalates, phytates and tannins has been reported. Stigmastane-type saponins such as vernoniosides, have been found abundantly in the leaves of Vernonia amygdalina. Some of the identified Sesquiterpene lactones are vernolide, vernodalol, vernolepin, vernodalin and hydroxyvernolide. Reports have established the presence of flavonoids in the leaves of Vernonia amygdalina.

Other phytochemicals present in the leaf of Vernonia amygdalina are terpenes, coumarins, phenolic acids, lignans, xanthones and anthraquinones. These phytochemicals are believed to be responsible for the plethora of bioactivities possessed by the plant.

Nwanjo reported that the aqueous leaf extract of Vernonia amygdalina reduced triacylglycerol levels and normalized cholesterol concentrations in the serum of diabetic rats. The ethanol leaf extract of the plant has also been reported to maintain the lipid profile of rats within normal range (taken as that of the control rats) when doses of 100 – 1000 mg/kg body weight were administered. It has been reported that Vernonia amygdalina has cardio-protective potential in Streptozocin (STZ) induced diabetic rats. These authors observed that the leaf extract of Vernonia amygdalina could protect the heart against impairment and complete destruction due to diabetes. Furthermore, Arhoghro et al. reported that Vernonia amygdalina protected against and also reversed the hepatic damage caused by tetrachloromethane-induced hepatotoxicity in albino rats. Iwalokun et al. also support the hepato-protective effect of Vernonia amygdalina in rats. Ethanol leaf extract of Vernonia amygdalina has been reported to protect against kidney impairment. Due to its numerous medicinal benefits, the leaf of Vernonia amygdalina has found wide application in various aspects of traditional medicine including its usage in the amelioration of toxic effects of chemical substances.


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