Cucurbita pepo used in the folkloric treatment of malaria, mediates anti-inflammatory, anti-nociceptive, antipyretic, and immunomodulatory effects in murine models

Malaria is an infectious disease that presents fever, inflammation of joints, vomiting, arthralgia, abdominal cramps, splenomegaly, hepatomegaly, and severe anemia in children. This study was undertaken to investigate the anti-inflammatory, anti-nociceptive, antipyretic, and immunomodulatory properties of Cucurbita pepo and its use as an adjunct in the treatment of malaria in Nigeria. The dried plant material (aerial parts) was extracted by cold maceration using 70.0% ethanol. The extract was characterized by GC-MS analysis and subjected to pharmacological evaluation in systemic and topical inflammation, acetic acid-induced nociception, and lipopolysaccharide-induced pyrexia. Its effect on the primary humoral immune response to sheep red blood cells was also assessed. Cucurbita pepo extract (CpE) revealed its major components to be palmitic acids (47.4%), 9-octadecanoic acid (10.8%), and 4-coumaric acid (5.3%). The extract suppressed paw inflammation in a dose-dependent manner, producing a significant effect at a dose of 900 mg/kg. CpE at 0.25, 1.25, and 2.5 mg inhibited topical inflammation by 17.2% to 39.0% and lymphocyte infiltration associated with the inflammatory response. At a dose of 900 mg/kg, CpE significantly reduced hyperthermia, and its effect was comparatively higher than that of indomethacin. The extract inhibited writhing response to abdominal pain, although its effect was statistically insignificant. Treatment with the extract also stimulated the immune response, evidenced by an increase in hemagglutination antibody titer and relative spleen weight in CpE-treated groups. Particularly, the extract evoked a stronger immunostimulatory response compared to levamisole, a standard immunostimulatory agent. These findings provide evidence to support the use of C. pepo in the treatment of symptoms associated with malaria.