In vitro effects and mechanisms of action of Bidens pilosa in Trypanosoma brucei

Aboagye Kwarteng Dofuor; Georgina Isabella Djameh; Michael Amoa-Bosompem; Samuel Kwain; Enoch Osei; Gilbert Mawuli Tetevi; Frederick Ayertey; Peter Bolah; Laud Kenneth Okine; Kwaku Kyeremeh; Theresa Manful Gwira; Mitsuko Ohashi

doi:10.1016/j.jtcme.2021.08.008

In vitro effects and mechanisms of action of Bidens pilosa in Trypanosoma brucei

J Tradit Complement Med. 2021 Aug 11;12(3):260-268. doi: 10.1016/j.jtcme.2021.08.008. eCollection 2022 May.

Authors

Aboagye Kwarteng Dofuor^{1

2}, Georgina Isabella Djameh³, Michael Amoa-Bosompem³, Samuel Kwain⁴, Enoch Osei⁴, Gilbert Mawuli Tetevi⁴, Frederick Ayertey⁵, Peter Bolah⁵, Laud Kenneth Okine^{1

6}, Kwaku Kyeremeh⁴, Theresa Manful Gwira^{1

6}, Mitsuko Ohashi^{3

7}

Affiliations

¹ West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana.
² Department of Biological, Physical and Mathematical Sciences, University of Environment and Sustainable Development, Somanya, Ghana.
³ Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
⁴ Marine and Plant Research Laboratory of Ghana, Department of Chemistry, University of Ghana, Legon, Ghana.
⁵ Center for Plant Medicine Research, Mampong-Akuapem, Ghana.
⁶ Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana.
⁷ Department of Environmental Parasitology, Tokyo Medical and Dental University, Tokyo, Japan.

Abstract

Background and aim: African trypanosomiasis poses serious health and economic concerns to humans and livestock in several sub-Saharan African countries. The aim of the present study was to identify the antitrypanosomal compounds from B. pilosa (whole plant) through a bioactivity-guided isolation and investigate the in vitro effects and mechanisms of action against Trypanosoma brucei (T. brucei).

Experimental procedure: Crude extracts and fractions were prepared from air-dried pulverized plant material of B. pilosa using the modified Kupchan method of solvent partitioning. The antitrypanosomal activities of the fractions were determined through cell viability analysis. Effects of fractions on cell death and cell cycle of T. brucei were determined using flow cytometry, while fluorescence microscopy was used to investigate alterations in cell morphology and distribution.

Results and conclusion: The solvent partitioning dichloromethane (BPFD) and methanol (BPFM) fractions of B. pilosa exhibited significant activities against T. brucei with respective half-maximal inhibitory concentrations (IC₅₀s) of 3.29 μg/ml and 5.86 μg/ml and resulted in the formation of clumpy subpopulation of T. brucei cells. Butyl (compound 1) and propyl (compound 2) esters of tryptophan were identified as the major antitrypanosomal compounds of B. pilosa. Compounds 1 and 2 exhibited significant antitrypanosomal effects with respective IC₅₀ values of 0.66 and 1.46 μg/ml. At the IC₅₀ values, both compounds significantly inhibited the cell cycle of T. brucei at the G0-G1 phase while causing an increase in G2-M phase. The results suggest that tryptophan esters may possess useful chemotherapeutic properties for the control of African trypanosomiasis.

Keywords: AAT, Animal African trypanosomiasis; AT, African trypanosomiasis; African trypanosomiasis; Apoptosis; Asteraceae; B. pilosa, Bidens pilosa L (whole plant); BPC, crude extract of B. pilosa; BPFD, Dichloromethane fraction of B. pilosa; BPFH, hexane fraction of B. pilosa; BPFM, methanol fraction B. pilosa; BPWB, water-butanol fraction of B. pilosa; Cell cycle; HAT, Human African trypanosomiasis; Necrosis; Trypanosomatidae; Tryptophan esters.