Antidermatophytic and Toxicological Evaluations of Dichloromethane-Methanol Extract, Fractions and Compounds Isolated from Coula edulis

Background: Coula edulis Bail (Olacaceae), is an evergreen tree growing to a height of 25-38 m. This study aimed at evaluating the antidermatophytic and toxicological properties of the stem bark of C. edulis extract as well as fractions and compounds isolated from it. Methods: The plant extract was prepared by maceration in CH2Cl2-MeOH (1:1 v/v). The fractionation of this extract was done by silica gel column chromatography. Antidermatophytic activities were assayed using agar dilution method. The acute and sub-acute toxicities of oral administrations of the extract were studied in rodents. Results: The crude extract of C. edulis displayed antidermatophytic activity against the tested microorganisms with highest activity against Microsporum audouinii and Trichophyton mentagrophytes. The fractionation enhanced the antidermatophytic activity in fraction F3 (MIC=0.62-1.25 mg/ml) compared to the crude extract (MIC=1.25-5 mg/ml). Further fractionation and purification of the fractions F2 and F3 gave respectively 3-O-β-D-glucopyranoside of sitosterol (MIC=0.20-0.40 mg/ml) and a mixture of β-sitosterol, stigmasterol and n-hexadecanoid acid (MIC=0.80 mg/ml). The median lethal doses (LD50) of the crude extract were 16.8 and 19.6 g/kg body weight (BW) in male and female mice, respectively. At 200 mg/kg BW, there was a decrease in body weight gain, food and water consumptions. Gross anatomical analysis revealed white vesicles on the liver of the rats treated with the extract at 200 mg/kg BW. This dose also induced significant (P<0.05) changes on hematological and biochemical parameters in rats after 28 days of treatment.