In-vitro Antimalarial Activity of Plicosepalus acaciae Extracts Against Plasmodium falciparum

The emergence of drug-resistant Plasmodium strains necessitates the continuous search for novel antimalarial agents. Plicosepalus acaciae (P. acaciae), a semi-parasitic mistletoe, is used in traditional medicine, but its antimalarial potential is underexplored. This study aimed to evaluate the in vitro antimalarial activity of P. acaciae leaf and stem extracts. Methanol and chloroform extracts of P. acaciae leaves and stems were prepared. Their antimalarial activity against the chloroquine-resistant K1 strain of Plasmodium falciparum (P. falciparum) was assessed using a SYBR Green I-based assay at concentrations of 500, 250, and 125 µg/mL. Artemisinin (51.20 nM/L) was used as a standard drug. The 50% inhibitory concentration (IC50) was determined for active extracts. The methanolic stem extract exhibited the highest antimalarial activity with an IC50 of 3.26±0.10 µg/mL and achieved 91% parasite growth inhibition at 500 µg/mL, comparable to the 90% inhibition observed with artemisinin. The methanolic leaf extract and chloroform extracts showed lower activity, with IC50 values of 12.57 ± 0.03 µg/mL and 13.93 ± 0.07 µg/mL (leaves), and 7.61 ± 0.01 µg/mL (stems), respectively. Plicosepalus acaciae extracts, particularly the methanolic stem extract, possess promising in vitro antimalarial activity against P. falciparum. These findings justify further investigation to isolate the active compounds and evaluate their efficacy in vivo.