In Vivo and In Silico Evaluation of the Anti-plasmodial Properties of the Ethanolic Fraction of Chromolaena odorata

Chromolaena odorata (L.) R.M. King & H. Rob commonly known as Siam weed is a member of the Asteraceae family and is widely distributed in West Africa. Aqueous decoction from the leaves of the plant is used in the traditional treatment of malaria in the Western parts of Nigeria. Hence, this present study sought to identify effective anti-malarial agents by exploring the anti-plasmodial activity of the ethanol fraction of C. odorata (COEF) through in vivo and in silico approaches.

The anti-plasmodial activity of the ethanol fraction was evaluated using the 4-day Peter’s test and the Ranes and Repository tests, while the chemical compounds identified in the fraction were docked against Pf glutathione-S-transferase (Pf GST), Pf falcipain 2 and 3, Pf plasmepsin, and Pf heat shock protein 90.

Treatment with 100, 200, and 400 mg/kg bw of the COEF showed strong curative, chemo-suppressive, and prophylactic anti-plasmodial activity against P. berghei. The promising action of the ethanol fraction of C. odorata competes favourably with chloroquine, artemether-lumefantrine, and pyrimethamine-sulfadoxine. In addition, the COEF improved the plasmodial infection-induced alterations in haematological parameters and the levels of immunoglobulin G and tumour necrosis factor-α. The molecular docking suggests that the anti-malarial activity of the fraction is likely due to the presence of quercetin, luteolin, and naringenin. The indicated molecules not only inhibit Pf GST, Pf falcipain 2 and 3, and Hsp90 but also have high binding affinity for more than one of the target proteins and fully comply with the Lipinski, Veber, Egan, Muegge, and Ghose rules of druglikeness. Collectively, the COEF exhibited promising antimalarial action, particularly a superior prophylactic antimalarial property relative to the standard drugs. In addition, our findings indicate that the COEF may serve as a source of promising therapeutic inhibitors of malaria infection.

The findings from this study show that the leaf of C. odorata possesses strong anti-plasmodial properties which validates its use in the traditional treatment of malaria. However, further studies are needed to investigate the safety and toxicological profile of the plant.