Growth Inhibitory and Cytotoxic Effects of the Methanol Extracts of <em>Ficus Exasperata</em> Vahl (Moraceae) Root Bark

Abstract

Ficus exasperata is a medicinal plant characterized by its coarse and abrasive simple leaves. In ethnomedicine, the root bark is used in treating tumor related ailments. The cytotoxic and anti-proliferative effects of the methanol extract of the root bark and its organic solvent fractions were examined using the tadpoles of Raniceps ranninus and radicle length of guinea corn Sorghum bicolor seeds respectively. The methanol extract showed significant concentration dependent toxicity on the tadpoles as the percentage mortality of 56.67±1.23 obtained at a concentration 10µg/ml was increased to 100 at 20 µg/ml. The chloroform and the aqueous fractions did not show remarkable effects although 100% mortality was obtained at 80 µg/ml with the chloroform fraction. The crude extract gave an LC₅₀ of 8.67µg/ml while the aqueous and chloroform fractions produced LC₅₀ values of 57.33 and 28.67 µg/ml respectively. The extract significantly (P<0.01) reduced the radicle length of the seeds treated with 0.5-4 mg/ml of the extract throughout the 96h incubation period. At 96h, the control seeds produced average length of 51.4 ± 2.72 mm while the seeds treated with 2 and 4 mg/ml had average lengths of 42.2 ± 1.63 and 31.8 + 2.71 mm respectively. The aqueous fraction was more effective than the chloroform fraction as it produced 47.56% reductions in radicle lengths compared with the controls. The results suggest the probable use of the plant in treating tumor related ailments and purification did not enhance activity.