Evaluating phytochemical constituents and in-vitro antiplasmodial and antioxidant activities of Fadogiella stigmatoloba, Hygrophylla auriculata, Hylodesmum repandum, and Porphyrostemma chevalieri extracts.

Introduction: Fadogiella stigmatoloba, Hygrophylla auriculata, Hylodesmum repandum and Porphyrostemma chevalieri are used against malaria in traditional medicine in the Democratic Republic of the Congo (DRC). To evaluate their potential in the treatment of this disease, the in vitro antiplasmodial property of these four plants was evaluated. All experiments were conducted on methanolic extracts performed on selected organ parts of these plants. Methods: The methanolic extracts, obtained by maceration, were firstly screened in vitro against the chloroquine sensitive (3D7) and resistant (W2) Plasmodium falciparum strains by the measurement of lactate dehydrogenase activity, and on human keratinocytes (HaCat) cells by the MTT assay to determine their selectivity indices (SI). Secondly, the antioxidant activity of the same extracts was evaluated using DPPH and FRAP assays. Finally, the presence of specific phytochemical constituents was evaluated using standard methods and tentatively identified by GC-MS. Results: An optimum antiplasmodial activity (IC50 = 3.4 ± 0.7 µg/mL, for 3D7, SI = 58.2; IC50 = 7 ± 1.0 µg/mL, for W2, SI = 28.3) was obtained with the leave extract of P. chevalieri. The leaves (for F. stigmatoloba and H. repandum), and the aerial part (for H. repandum) extracts showed promising and moderate antiplasmodial activities against respectively the 3D7 strain (IC50: <15 µg/mL), and W2 strain (IC50:15-50 µg/mL). All extracts presented a weak cytotoxic effect (IC50: >100 µg/mL) on HaCat cells. For the antioxidant test, the most interesting activity was obtained with the leaf extract of P. chevalieri. The GC-MS analysis of these four plants species extracts revealed the presence of various compounds, such as Ethyl 2-nonenoate, 2-(2-Hydroxy-2-phenylethyl)-3,5,6-trimethyl pyrazine, Palmitic Acid, Ethyl palmitate, Ethyl linolenate, and N-Acetyltyramine. Conclusion: Based on the obtained results, P. chevalieri could be selected for further investigations or /and for the management of malaria after standardization.