Comparative antiplasmodial, mito-protective and anti-inflammatory potentials of Phyllanthin and Stigmasterol-methyl siaresinolate mixture from Phyllanthus amarus in Plasmodium berghei-infected mice.

Phyllanthus amarus Schum. & Thonn is a medicinal plant, documented for its folkloric use in the treatment of malaria. This study investigated the antimalarial potential and mechanism of action of bioactive compounds purified from Phyllanthus amarus. Through bioactivity-guided assay, the dichloromethane fraction was obtained from the methanol extracts, and Phyllanthin, Stigmasterol-methyl siaresinolate mixture were purified from it using chromatographic and spectroscopic techniques. Thirty male mice were infected with Plasmodium berghei (ANKA strain) and treated after parasitemia confirmation for five consecutive days. Percentage parasitemia and chemosuppression were determined using microscopy. Host mitochondrial permeability transition (mPT) pore opening, FoF1 ATPase, and lipid peroxidation were determined using spectrophotometry. Inflammatory cytokines, biomarkers for liver toxicity and some glycolytic enzymes were assessed using ELISA. Gene expressions for mitochondrial complexes, matrix metalloproteinases (MMP2) and MMP9, creatine kinase, and troponins (TnI, TnC, and TnT), Janus kinase (JAK), aquaporin-3 (AQP3), and cGMP were determined. At 10 mg/kg, the Stigmasterol-Methyl siaresinolate mixture had the highest chemo-suppression and the least percentage parasitemia, reversed the mPT pore opening, decreased FoF1 ATPase activity, and lipid peroxidation. The compounds decreased inflammatory biomarkers, markers for liver toxicity, and modulated glycolytic enzymes. These compounds enhanced mitochondrial complexes, cGMP, and MMP2 and MMP9 expressions while it downregulated the expressions of AQP3, Creatine kinase, TnI, TnC, and TnT, as well as JAK genes. These compounds may have exerted this effect through mitochondrial protection, modulation of metabolic and inflammatory pathways, and regulation of gene expression, supporting their potential as therapeutic candidates for drug-resistant malaria.