Phytochemical screening and promiximate composition and onion bulb ( Allium cepa L)

The phytochemical constituents and proximate composition of onion ( Allium cepa L. ) were investigated. The light scaly leaves on the onion bulbs were removed and the fleshy parts chopped into tiny pieces, dried in an air-circulating oven in the laboratory and ground into fine powder using a mechanical grinder. Phytochemical studies were carried out on the resulting powdered extract. The secondary metabolites in the bulb were screened and identified. A proximate analysis was also ran to determine the moisture content, ash value, protein, fats, carbohydrate and fibre value of the bulb. The results of the phytochemical screening showed that carbohydrates, glycosides, proteins, alkaloids, saponins, flavonoids, acid compounds, reducing sugars and oils were present while steroids were absent. Similarly, the results of the proximate analysis showed that onion bulb contains mostly carbohydrates(78.36%) and crude protein (11.53%) while crude fat and crude fibre had the least concentrations of 0.97 and 0.07 % respectively. The research has indicated that onion is widely used around the world as a food product and has also been used for medicinal applications. It has a very long folkloric history of use in a wide range of ailments. Keywords : Allium cepa , phytochemistry, proximate analysis, Alliaceae, allicin, methanolic extraction Journal of Pharmaceutical and Allied Sciences , Vol. 7 No. 2 (2010)