Evaluation of in vitro antiplasmodial, antiproliferative activities, and in vivo oral acute toxicity of Spathodea campanulata flowers

Spathodea campanulata is used in traditional medicine to treat various ailments such as malaria, human immunodeficiency virus (HIV), cancer, fever and urethral inflammation. The aim of this study was to investigate the antiplasmodial, and antiproliferative activities of the extract and resulted fractions from S. campanulata flowers, as well as assessing the acute toxicity of its aqueous fraction. The in vitro cell-growth inhibition activities were assessed against Plasmodium falciparum strain 3D7 for antimalarial activity and three cancer cell lines: Hs683 (human oligodendroglioma), MCF7 (human breast carcinoma), and murine B16F10 (mouse melanoma) for antiproliferative activity while the in vivo acute oral toxicity was determined according to the modified organisation for Economic Co-operation and Development (OECD) guidelines 423 at a fixed dose on Female Wistar strain laboratory rats. The dichloromethane, ethyl acetate and hexane fractions at a concentration of 25 µg/mL each significantly reduced the viability of 3D7 Plasmodium cells with viability percentages of 19.0%, 14.1% and 31.9%, respectively, and IC₅₀ of 28.1, 30.2 and 29.7 µg/mL, respectively. The ethyl acetate fraction showed a moderate antiproliferative activity on mouse melanoma with an I₅₀ value of 54.6 µg/mL. Only the dichloromethane fraction was able to inhibit the 3 cell lines tested with IC₅₀ values less than 15 µg/mL. An oral administration of the aqueous fraction did not induce an abnormal variation of the physiological parameters in female Wistar laboratory rats, at non-toxic doses up to 5000 mg/kg body weight for 14 days. These results confirm the use of this plant in traditional medicine for its antimalarial and anticancer potential.