1.1 BACKGROUND OF THE STUDY
Plants have been used for centuries before the advent of Orthodox medicine. Leaves, flowers, stems, roots, seeds, fruit and bark can all be constituents of herbal medicines. The medicinal values of these plants depend on their phytochemical components, which produces definite physiological actions on the human body. The most important of these phytochemicals are alkaloids, tannins, flavonoids and phenolic compounds (Afolabi et al., 2007; Okorondu et al, 2010). Moringa is the sole genus in the flowering plant family Moringaceae. The genus Moringa in turn is made up of 12 species. Moringa oleifera is the most widely cultivated species of the genus Moringa and it is found in many tropical and sub-tropical regions (Sofowora, 1984). M. oleifera is cultivated and harvested in many areas of the world where other plants are unable to thrive and virtually every part of the Moringa tree can be used for food, medicine or put some other beneficial use (Farooq et al., 2007). The “Moringa” tree is grown mainly in semi-arid, tropical and subtropical areas. It grows best in dry sandy soil, tolerates poor soil, including coasted areas. M. oleifera, commonly referred to as the miracle tree, is the most widely cultivated species of the genus Moringa, which is the only genus in the family Moringaceae. It is a fast growing and resistant shrub, native to India but now widely distributed in the tropics and subtropical areas (Oliver-Bever, 2000). In Nigeria, M. oleifera is encountered doing well in all ecological zones where it is always in season all the year round. The plant is propagated by both seeds and cuttings. The Moringa tree is grown mainly in semi-arid, tropical and subtropical areas. Today, it is widely cultivated in Africa, Central and South America, Sri- Lanka, India, Mexico, Malaysia, Indonesia and the Philippines. It is considered one of the World’s most useful trees, as almost every part of the Moringa tree can be used for food or has some other beneficial property (Fahey, 2005).
Jatropha curcas is a plant which belongs to the family Euphorbiaceae originated from Mexico and South Africa (Tint and Mya, 2009). The plant was introduced to Africa by the Portuguese in 1500 and was found growing sparsely in the wild in Nigeria and was use as hedge (Lozan, 2007). It is easy establish and grows relatively quickly producing seeds for 50 years. It is usually propagated by seed. (okorodun et al.,2013)