Growth inhibitory and cytotoxic effects of the methanol extract of Brachystegia eurycoma Harms (Fabaceae) leaves

Brachystegia eurycoma Harms (Fabaceae) is used Nigeria for its anti-inflammatory, anti-malaria, anti-diabetics, and antihypertensive properties in combination with other plants. The seeds have particularly served as thickener in certain soups like ‘ egusi ’ and ‘ ogbono ’ in the eastern part of Nigeria. The growth inhibitory and cytotoxic effects of the methanol extract of the leaves and its organic solvent fractions were evaluated on the radicles of guinea corn Sorghum bicolor seed and tadpoles of Raniceps ranninus respectively. The extract and the aqueous fraction completely inhibited the germination of the guinea corn seeds in 24 h at a concentration of 20 mg/ml. The lengths of the radicles produced were significantly (<0.05) reduced with increase in the concentration of the extract and the fractions. The extract had an IC 50 of 5 mg/ml while the aqueous fraction was observed to have 1.61 mg/ml. The cytotoxic effects of the tested extract and its fractions were observed to be concentration and time related. The aqueous fraction produced 100 % mortality at the concentration of 100 μg/ml with LC 50 of 30 μg/ml whereas the extract produced 96.67 ± 3.33 % mortality at 200 μg/ml with LC 50 of LC 50 of 62.5 μg/ml. In conclusion, the results obtained confirmed the probable use of B. eurycoma leaves in treating tumour related ailments and the activities are enhanced with partial purification with the aqueous fraction showing higher activities. Keywords: Brachystegia eurycoma , Growth inhibitory effects; Cytotoxic.