AN ASSESSMENT OF THE HEPATOPROTECTIVE EFFECTS OF SENNA TORA LEAF EXTRACT ON CARBON TETRACHLORIDE INDUCED TOXICITY
Senna tora leaves are used as traditional medicine in Africa for the treatment of many disorders. In Cameroon, the leaves of this plant are used for the treatment of convulsions and malaria. No work has been interested on the anticonvulsant activity and toxicity of Senna tora as affected by solvent extraction. This study has the objective to evaluate the anticonvulsant activity and toxicity of Senna tora extracts. The extracts were produced by maceration in 4 different solvents (water, ethanol, methanol and hydroethanol) and by decoction. Several doses (45, 112.5, 225 and 450 mg / kg) of the five Senna tora extracts were tested for their efficacy against convulsion induced by bicuculin, kainic acid, strychnine and picrotoxin. Normal, negative and positive (phenobarbital and clonazepam treatment) control treatments were equally tested. Firstly, the animal received the treatment (per os), after 1 hour all they animals received the injection of convulsivant solution except normal control. Latency time and duration of convulsion were noted. For acute toxicity, the animals received one dose (5000mg/kg) of the different extracts and were observed during 7 days. As results, it appeared that the methanolic, ethanolic and hydroethanolic extract at the dose 450 mg/kg protected 80% of mice against convulsion induced by strychnine, picrotoxin. In addition, the plant induced a significant decreased of the duration of convulsions. Moreover, no dead nor toxicity were observed for administration doses less than 5000 mg/kg body weight. Definitively, Senna tora extracts exhibit anticonvulsant and are not toxic, thus pointing out the use of the plant in the treatment of epilepsy.
1.1 BACKGROUND OF THE STUDY
Medicinal plants play a key role in the human health care. About 80% of the world population rely on the use of traditional medicine which is predominantly based on plant materials 1. The traditional medicine refers to a broad range of ancient natural health care practices including folk/tribal practices as well as Ayurveda, Siddha, Amchi and Unani. These medical practices originated from time immemorial and developed gradually, to a large extent, by relying or based on practical experiences without significant references to modern scientific principles.
These practices incorporated ancient beliefs and were passed on from one generation to another by oral tradition and/or guarded literature. Although herbal medicines are effective in the treatment of various ailments very often these drugs are unscientifically exploited and/or improperly used. Therefore, these plant drugs deserve detailed studies in the light of modern science.
It is estimated that about 7,500 plants are used in local health traditions in, mostly, rural and tribal villages of India. Out of these, the real medicinal value of over 4,000 plants is either little known or hitherto unknown to the mainstream population. The classical systems of medicine such as Ayurveda, Siddha, Amchi, Unani and Tibetan use about 1,200 plants 2. A detailed investigation and documentation of plants used in local health traditions and pharmacological evaluation of these plants and their taxonomical relatives can lead to the development of invaluable plant drugs for many dreaded diseases. Random screening of plants has not proved economically effective 3.
Liver diseases and medicinal plants: Liver has a pivotal role in regulation of physiological processes. It is involved in several vital functions such as metabolism, secretion and storage. Furthermore, detoxification of a variety of drugs and xenobiotics occurs in liver. The bile secreted by the liver has, among other things, an important role in digestion. Liver diseases are among the most serious ailment. They may be classified as acute or chronic hepatitis (inflammatory liver diseases), hepatosis (non inflammatory diseases) and cirrhosis (degenerative disorder resulting in fibrosis of the liver). Liver diseases are mainly caused by toxic chemicals (certain antibiotics, chemotherapeutics, peroxidised oil, aflatoxin, carbon-tetrachloride, chlorinated hydrocarbons, etc.), excess consumption of alcohol, infections and autoimmune/disorder.
Most of the hepatotoxic chemicals damage liver cells mainly by inducing lipid peroxidation and other oxidative damages in liver. Enhanced lipid peroxidation produced during the liver microsomal metabolism of ethanol may result in hepatitis and cirrhosis 4. It has been estimated that about 90% of the acute hepatitis is due to viruses. The major viral agents involved are Hepatitis B, A, C, D (delta agents), E and G. Of these, Hepatitis B infection often results in chronic liver diseases and cirrhosis of liver. Primary liver cancer has also been shown to be produced by these viruses.
It has been estimated that approximately 14- 16 million people are infected with this virus in South East Asia region and about 6% of the total population in the region are carriers of this virus. A vaccine has become available for immunization against Hepatitis B virus. Hepatitis C and Hepatitis E infections are also common in countries of South East Asia region 5.
In the present work, authors had reviewed the articles of hepatoprotective activity of the medicinal plants and has arranged them in the systemic order as shown in table