Identification of the Key Aroma Compounds in Dried Fruits of Xylopia aethiopica

West African “Peppertree” [Xylopia aethiopica (Dunal) A. Rich, Annonaceae] is a slim, tall tree of about 60–70 cm in diameter and up to 15–30 m high with straight stem and a slightly stripped or smooth bark. It is widely distributed in the humid forest zones of West Africa especially along rivers in the dry country sides (Irvine 1961). Xylopia aethiopica has a wide variety of application, the very odorous roots of the plant are employed in West Africa in tinctures, administered orally to expel worms and other parasitic animals from the intestines, or in teeth-rinsing and mouth-wash extracts against toothaches. The fruits are also used in various forms and exhibit revulsive properties, especially when mashed with grains. These properties are used advantageously in the external treatment of rheumatism. Crushed powdered fruits can also be mixed with shea butter fat and coconut oil and used as creams, cosmetic products, and perfumes (Burkill 1985), and the dried fruits are also used as spices in the preparation of two special local soups named “obe ata” and “isi-ewu” taken widely in the southwest and southeastern parts of Nigeria. Ekong and Ogan (1968), were the first to report on the chemical composition of Xylopia aethiopica, and several publications have appeared subsequently on this subject. A number of diterpenes from the bark, fruits, and pericarp of the plant have been reported, Faulkner et al. (1985); Rabunmi and Pieeru (1992); Harrigan et al. (1994). Ekundayo (1989) published a review of the volatiles in a number of Annonaceae species among which includes Xylopia aethiopica and, reported that they consist mainly of mono and sesquiterpenoids with typical constituents being aand b-pinene, myrcene, p-cymene, limonene, linalool, and 1,8-cineole. Recently, two new sesquiterpenes, elemol and guaiol (among other terpenes) were found in the essential oil of the fruit from the Republic of Benin (Ayedoun et al. 1996) while Jirovetz et al. (1997) gave a semblance of the aroma note from the essential oil in the fruit of Xylopia aethiopica from Cameroon. No attempt had been undertaken to rank the volatiles in their flavor contribution. In order to detect these compounds, volatiles isolated from the crushed dried fruits of Xylopia aethiopica from Nigeria have been analyzed by High-Resolution Gas Chromatography (HRGC) and eluate sniffing.