Anti-plasmodial and anti-apoptotic effects of walnut leaf extracts on mice infected with Plasmodium berghei

Abstract

Malaria, primarily caused by Plasmodium parasites, remains a major public health challenge, especially in regions with emerging drug resistance. Among the Plasmodium species, Plasmodium berghei ( Pb ) induces severe infections in experimental models. This study investigated the anti-apoptotic effects of walnut ( Juglans regia L.) leaf extract (JRLE) in C57BL/6 mice infected with Pb . Methanolic extracts of JRLE were characterized using LC-ESI-MS, revealing alkaloids, phenolics, flavonoids, anthocyanins, fatty acids, and sterols. Six groups of female mice ( n  = 5 each) were established, including controls, non-infected JRLE-treated, and Pb -infected groups treated with JRLE (250 or 500 mg/kg) or chloroquine (10 mg/kg). Pb infection was induced intraperitoneally, and treatments were administered orally from day 4 to 8. Blood and brain samples were collected on day 9 for hematological and immunohistochemical analyses, and parasitemia, suppression rates, and feed intake were assessed. JRLE significantly reduced parasitemia (43.87 % at 250 mg/kg; 72.84 % at 500 mg/kg), improved feed intake, restored hemoglobin and erythrocyte levels, and normalized white blood cell counts. Additionally, JRLE lowered elevated caspase-3 expression in infected mice, indicating a protective effect against apoptosis. These findings suggest that walnut leaf extract, rich in bioactive phytochemicals, may offer anti-plasmodial activity and reduced brain caspase-3 signal in malaria infection.