Anti-proliferative study and isolation of Ochnaflavone from the ethyl acetate-soluble fraction of Ochna kibbiensis Hutch & Dalziel.

Anti-proliferative activity of the ethyl acetate fractions of Ochna schweinfurthiana F. Hoffm. and Ochna kibbiensis Hutch. and Dalziel methanol leaf extracts were investigated against glioblastoma multiforme (GBM U-1242 MG) cell line. O. kibbiensis significantly (p < 0.001) and dose dependently (IC50 = 25.74 μg/mL) reduced cell count. At 125 μg/mL, O. kibbiensis extract reduced cell count by about 92% compared to the untreated control. On the other hand, at 125 μg/mL, O. schweinfurthiana extract reduced cell count only by 20%, indicating a much weaker activity (IC50 = 823.51 μg/mL). Following from the result obtained, ethyl acetate fraction of O. kibbiensis was subjected to chromatographic purification. This led to the isolation of ochnaflavone; the structure of the isolated compound was identified by analysis of its nuclear magnetic resonance (NMR) spectral data and comparison with data in the literature. Although the isolated ochnaflavone could not be tested for anti-proliferative activity due to insufficient quantity, the obtained results indicate the presence of bioactive anti-GBM principles in O. kibbiensis.