Biochemical Characterization of the Unsaponifiable Fraction of Coula edulis Oil Collected at Sembé

Abstract

Coula edulis Baill., is a non-timber forest product which represents a considerable food, cultural and economic stake for the populations of Central Africa. It belongs to the order of Olacales and the family of Olacaceae. The unsaponifiable fraction of the oil of Coula edulis Baill. from Sembé, extracted by Soxhlet (NF ISO 82 62-3) with n-hexane was the subject of this study. The extracted fat content is: 25.91 ± 0.16% per 100 g of almonds. Conventional methods were used to characterize the unsaponifiables of this oil: Extraction with diethyl ether (NF EN ISO 3596) to determine the content of unsaponifiables; High Performance Liquid Chromatography (NF EN ISO 9936) for tocopherols and tocotrienols; determining the content of individual and total sterols (NF EN ISO 12228); total polyphenols by Folin's method and alkanes by HPLC-GC-FID coupling. We obtained: Tocopherols and Tocotrienols (α-tocopherol acetate <5 mg/Kg of fat, α-tocopherol, β-tocopherol, γ-tocopherol, Δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol, Δ-tocotrienol <2 mg/Kg of fat for each molecule); Sterols: β-sitosterol (49.3%), Stigmasterol (41.3%), Δ5-avenasterol (3%), Campesterol (1.5%), Δ7-stigmastenol (1.2%), Clerosterol (1% ), Sitostanol (0.9%), Cholesterol (0.8%), Δ5,24-Stigmastadienol (0.8%), Brassicasterol, 24-methyl-cholesterol, Campestanol, Δ5, 23-stigmastadienol and Δ7- avenasterol 0.1% for each of the molecules. The content of total sterols is: 959 mg/Kg, that of total polyphenols, 34 mg/Kg and that of alkanes, 98 mg/Kg. These molecules are of paramount importance in human nutrition and in medicine.