Evaluating the Antiplasmodial Activity of <i>Picrasma javanica</i> Stem Bark Extract and Its Synergy With Artesunate in Rodent Malaria Models

Malaria remains a global health challenge, exacerbated by the emergence of drug-resistant <i>Plasmodium</i> strains. This study evaluates the antimalarial activity of <i>Picrasma javanica</i> stem bark extract and its combination with artesunate (ART) in <i>Plasmodium berghei</i>-infected mice. The extraction yield using hexane at a 1:5 (w/v) ratio was 7.8% w/w. Acute toxicity assessment indicated no mortality or adverse effects at doses up to 2000 mg/kg. In suppressive activity tests, <i>P. javanica</i> stem bark extract exhibited dose-dependent efficacy, achieving 13.3%, 36.4%, and 52.5% parasitemia inhibition at doses of 100, 200, and 400 mg/kg, respectively, with significant inhibition at higher doses (<i>p</i> < 0.05 and <i>p</i> < 0.01). ART showed 90.7% suppression (<i>p</i> < 0.001). In curative tests, the extract at 400 mg/kg reduced parasitemia by 31.0% (<i>p</i> < 0.05), while ART achieved 75.3% suppression (<i>p</i> < 0.001). The effective dose (ED₅₀) values were 404.9 mg/kg for <i>P. javanica</i> stem bark extract and 2.03 mg/kg for ART. Combination treatments at ED₅₀ ratios of 40/60 and 20/80 (extract/ART) resulted in 65.9% (<i>p</i> < 0.01) and 81.7% (<i>p</i> < 0.001) inhibition, respectively, with the 20/80 ratio showing a significant synergistic interaction (CI = 0.44121). The mean survival time (MST) for the untreated group was 12.2 ± 1.9 days. <i>P. javanica</i> stem bark extract and ART alone extended MST to 21.4 ± 2.4 and 21.8 ± 2.4 days, respectively (<i>p</i> < 0.05), while the 20/80 combination achieved the longest MST of 28.6 ± 1.7 days (<i>p</i> < 0.01; <i>p</i> < 0.05 vs. monotherapies). These findings highlight the potential of <i>P. javanica</i> stem bark extract as a complementary antimalarial agent when used with ART, offering a promising approach for combating drug-resistant malaria.