African Journal of Biotechnology Vol. 5 (11), pp. 1154-1160, 2 June 2006 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2006 Academic Journals Full Length Research Paper Comparative studies on Khaya. A. Juss (Meliaceae) in Nigeria Jemilat A. Ibrahim 1 *, Emmanuel A. Ayodele 2 , Adeola I. Jegede 1 and Yemisi F. Kunle 1 1 Department of Medicinal Plant Research and Traditional Medicine, NIPRD, Abuja. Nigeria. 2 Department of Botany and Microbiology, University of Ibadan, Ibadan, Nigeria. Accepted 3 May, 2006 Comparative phytochemical, microscopical and chemomicroscopical studies were carried out on the genus Khaya with the aim of obtaining useful characters for the identification and delimitation of species boundaries. Tannins and saponins were present in all the species while phenols were detected in all except K. grandifoliola. Protein and anthraquinones were present in the bark of all the species. Carbohydrate is present in all the species except in the bark of K. ivoriensis. Flavonoids and phlobatannins were absent in all the taxa. Microscopical examination of the powdered bark revealed different types and shapes of lignified sclereids, abundant distribution of prismatic calcium oxalate crystals, druses, lignified cork-cells, fibres, medullary rays and parenchyma cells which may contain starch grains. Key word: Khaya, microscopy, phytochemistry, taxonomy, chemomicroscopy. INTRODUCTION Khaya A. Juss belongs to the family Meliaceae. Five species of this genus occur in Africa with four species in West Africa. These are Khaya anthoteca (Welw.) C. Dc., K. senegalensis (Desv.) A. Juss, K. ivoriensis A. Chev. and K. grandifoliola C. Dc. (Hutchinson and Dalziel, 1954). One species, K. nyasica Stapf. ex E. G. Baker, was introduced from Central Africa. The West African species are commonly referred to as African mahogany. While the Yorubas in Nigeria call the species ‘oganwo’, the Hausas and Igbos call them ‘madachi’ and ‘ono’ respectively. The genus is easily recognized by its round or mainly spherical woody capsules which are about 4 - 5 valved and dehiscent. The wood of Khaya is fairly hard, mostly odourless, durable and resistant to insect attack due to the presence of oleo-resin in their vessels. These qualities make them a valuable source of timber (Dalziel, 1948). Khaya species are highly priced in traditional medicine in West Africa. The main part used is the very bitter bark. *Corresponding authors E-mail: sadiqoyene@yahoo.com. The uses range from the treatment of fever, lumbago, cough, rheumatism and stomach ache to gastric pains (Kerharo and Banquet, 1950). In veterinary medicine, the bark is also used in the treatment of worm infestation, ulcer and mucous diarrhoea in horses and Camels (Dalziel, 1948). The juice from the pulped roots of K. ivoriensis is used together with Piper guineense Schum.and Thonn. as enema for dysentery and the bark decoction is drunk for lumbago as well as rheumatic pains (Irvine, 1961). The wood ash of K.senegalensis is used for storing millet seeds to preserve them for planting the following year (Irvine, 1961; Ashvine, 2001). Olowokudejo and Nyananyo (1990) first reported the epidermal morphology of the genus Khaya and conclu- ded that the micro morphological characters of the leaf are useful in the identification of the species even if only their leaf fragments are available. The present study focuses on the comparative phytochemical investigation of the leaves and stems bark of the species with a view to obtaining additional characters for the identification and delimitation of the species as well as establish the chemical basis for the traditional uses of the taxa in medicine. Furthermore, the organoleptic and microsco-