PROJECT TOPIC- ACTIVITY OF CHLOROFORM-ETHANOL EXTRACTS OF CASHEW (Anacardium occidentale) KERNEL IN CASTOR OIL-INDUCED DIARRHOEA IN RATS
The anti-diarrhoeal activity of ethanol-chloroform extracts of Anacardium occidentale kernel at the doses of 21 and 84 mg/kg body weight were studied using rat models of diarrhoea, enteropooling and gastro-intestinal motility induced castor oil. The results of the qualitative phytochemical analysis showed that the ethanol-chloroform extracts (ethanol, chloroform and middle layers) tested positive to flavonoids, alkaloids, saponins, reducing sugars, glycosides and steroids, while chloroform layer and middle layer tested positive to fat and oil. Acute toxicity and lethality studies on ethanol-chloroform extracts revealed an oral LD50 equal to or more than 5000 mg/kg body weight in mice. The results showed that over a period of 5 hours the extracts significantly (p<0.05) reduced the watery texture and number of faecal droppings in treated groups compared with the untreated group. The extracts also significantly (p<0.05) reduced the volume and weight of intestinal content compared to the control animals. On gastro-intestinal motility, the extracts significantly (p<0.05) reduced the small intestinal transit of charcoal meal in rats induced with castor oil. The extracts also significantly (p<0.05) reduced the intestinal sodium and potassium ion (Na+ and K+) concentrations compared with animals in the untreated groups. These results showed that kernels of A. occidentale possess anti-diarrhoeal properties through inhibition of hyper-secretion, enteropooling and gastro-intestinal motility which can substantiate its use in the treatment of diarrhoea in traditional medicine.
Plants and their derivatives play key role in world health and have long been known to possess biological activity. Thirty percent of all modern drugs are derived from plants (Riaz et al., 2010). According to the World Health Organization, about 80% of the world’s population relies essentially on plants for primary health care (Mckay and Blumberg, 2007).
In our traditional civilization, the healers used to occupy a special place within the community; but with the advent of modern orthodox need, they are fast losing relevance. Nigeria and indeed black Africa has been witnessing the gradual disappearance of traditional healers, as well as a decline of their knowledge. By putting much effort into research on plants in the sphere of ethno-medicine, it is possible to revive knowledge of traditional mode of healing (Mustapha and Hafsat, 2007).
Diarrhoea is a major health problem especially in developing countries. In Africa, diarrhoea remains a major contributor to the high rate of child mortality. In Nigeria, diarrhoeal infection is probably the number one killer disease among children under 5 years (Magaji et al., 2010). Each year, there are approximately 4 billon cases of diarrhoea world wide leading to 4 million deaths especially among children in this age group (Azubuike and Nkagineme, 2007). Also, in this age group, 38% of all deaths are associated with diarrhoeal diseases (WHO, 1990) with 7-12 month-old babies being the most susceptible (Audu et al., 2010).
PROJECT TOPIC- ACTIVITY OF CHLOROFORM-ETHANOL EXTRACTS OF CASHEW (Anacardium Occidentale) KERNEL IN CASTOR OIL-INDUCED DIARRHOEA IN RATS
Diarrhoea is defined by the World Health Organization as the presence of three or more loose or liquid stools per day, or as the presence of more stools than is normal for that person. The incident of diarrhoeal diseases still remains high despite the intervention of government agencies and international organizations to halt the trend (Magaji et al., 2010). The use of herbal drugs in the treatment of diarrhoea is a common practice in many African countries (Agunu et al., 2005). Despite immense technological advancement in medicine, many people in developing countries still rely on traditional healing practices and medicinal plants for their health care needs (Ojewole, 2004).
The World Health Organization (WHO) encourages studies onto traditional medicinal prevention of diarrhoeal diseases (Alta and Mouneir, 2004). Therefore, there is urgent need for intensification of research into medicinal plants claimed to be effective in the management of diarrhoeal diseases (Mohammed et al., 2009).
The cashew (Anacardium occidentale) is a well known member of the Anacardiaceae family and is commonly found in Northeast Brazil. The cashew nut has been commercially exploited since colonization. Brazil, India and Mozambique are the leading cashew nut producers in the world (Pimentel et al., 2009).
Anacardium occidentale, an evergreen, multi-branched shrub of the Anacardiacea family, commonly known as cashew, attains a height of about 12 meters and has a spread of 25 m. The kernels of the plant have been reported to have antidiarrhoeal effect (Orwa et al., 2009).
1.1 Anacardium occidentale
Description of the plant The cashew (Anacardium occidentale) plant is a well known member of the Anacardiaceae family and is commonly found in northeast Brazil (Paramashiva et al., 2001).
A medium-sized tree, much branched, grows to a height of 12 meters. When growing on lateritic gravel or coastal sandy areas, it rarely exceeds 6m and develops a spreading habit and globose shape with crown diameter to 12 cm. When growing on loamy soil, it reaches 15m and is much branched, with smaller (94-96 m) crown diameter. The root system of a mature Anacardium occidentale when grown from the seed consists of a very prominent tap root, a well developed and extensive network of lateral and sinker roots.
Its leaves are simple, alternate, glabrous, round at ends, 10-18 × 8-15cm with short petiole (Orwa et al., 2009). When young, the leaves are pale green or reddish and are dark green when mature. The inflorescence is a terminal panicle-like cluster commonly bearing male and hermaphroditic flowers. The male flowers usually bear one exerted stamen and nine small inserted ones. Anacardium occidentale normally comes into flowering in 3-5 years. It has light grey back that is smooth when young but develops small cracks with increased age, it has potential as a soil stabilizing plant because it tolerates drought and is able to grow on relatively dry infertile soils and still provides some financial returns (Orwa et al., 2009).
The thin-skinned edible cashew fruit has a light yellow spongy flesh, which is very pleasantly acidic and slightly astringent when eaten raw and highly astringent when green.
The generic name was given by Lineaus and refers to the vaguely health shaped look of its false fruit (Orwa et al., 2009). Cashew apple juice is a rich source of vitamin C (ascorbic acid) and presents functional properties such as prevention of cancer and Helicobacter pilori – bacteria that cause severe gastritis; besides, presenting antioxidant properties (Joelia et al., 2006). In the main producing areas of East Africa and India, 95% or more of the apple crop is not eaten, as the taste is not popular.
However, in some parts of South America and West Africa, local inhabitants regard the apple rather than the kernel as a delicacy (Orwa et al., 2009). The nut which is the true fruit dries and does not split open. Inside the poisonous shell is a large curved seed, nearly 2.5cm long which is the edible cashew kernel. As the nut matures, the stalk (receptacle) at the base enlarges rapidly within a few days into the fleshy fruitlike structure, broadest at the apex, popularly known as the fruit (Orwa et al., 2009).
In 1970s, Africa was the largest producer of cashew nuts accounting for 67.5% of world production. This subsequently declined to 35.6% by 2000, with Nigeria, Tanzania and Mozambique being largest producers. The production in Asia during the same periods increased from 26.8% to 49.5% with the major producer being India, Indonesia and Vietnam. Similarly, the production in South and Central America also rose from 4.5% in 1970 to 14.5% in 2000 with Brazil and El Salvador being the leading producers (Hammed et al., 2008).