Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 18 3 2024 09 30 264 275 Alireza Naziri Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Afsaneh Motevali Haghi Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mehdi Nateghpour Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran, Center for Research of Endemic Parasites of Iran, Tehran University of Medical Sciences, Tehran, Iran Mohammad Shabani Department of Biochemistry, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Ahmad Dehdast Department of Biochemistry, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Abbas Rahimi Foroushani Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Aram Khezri Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Zahra Farzaneh Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2023 10 15 2025 03 28 Background: The global rise in malaria parasite resistance to antimalarial drugs necessitates new therapeutic strategies. Medicinal plant extracts, long used in traditional malaria treatment, have shown antiplasmodial potential in recent stud­ies. This study investigated the effects of nano tannic acid MgO (NTA MgO) and chloroquine (CQ), both individually and in combination, on a chloroquine-sensitive Plasmodium berghei strain. Methods: BALB/c mice infected with P. berghei were divided into 11 groups. Groups were treated with NTA MgO (12.5, 25, 50, 100 mg/kg), CQ (1, 3, 10, 20 mg/kg), pure tannic acid (100 mg/kg), or assigned as controls. Peter's meth­od determined the fifty percent effective dose (ED50) for NTA MgO and CQ. Drug interactions were assessed using the fixed-ratio method (ratios: 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, 0/100). Parasitemia and inhibition percentages were calculated and analysed using SPSS software. Results: The ED50 values for CQ and NTA MgO were found to be 1.1 mg/kg and 25 mg/kg, respectively. A synergistic effect was observed when a combination of 30% CQ and 70% NTA MgO was used, which significantly reduced para­sitemia compared to the control group (P< 0.05, Kruskal-Wallis test). Additionally, NTA MgO administered alone at a dosage of 25 mg/kg effectively reduced the parasite load. Conclusion: NTA MgO showed strong antiplasmodial activity both alone and with chloroquine (CQ). The 30% CQ and 70% NTA MgO combination exhibited a significant synergistic effect, highlighting its potential as a new treatment for chloroquine-sensitive malaria and the promise of plant-based nanoparticles against drug-resistant malaria. https://jad.tums.ac.ir/index.php/jad/article/view/1691 https://jad.tums.ac.ir/index.php/jad/article/download/1691/669