Exploring Vitamin C as an Adjunct Therapy in Neglected Tropical and Parasitic Diseases: A Review of Preclinical Evidence

Abstract

Neglected tropical diseases (NTDs) and parasitic infections (such as leishmaniasis, malaria, Chagas disease, schistosomiasis) disproportionately impact poor populations worldwide. Existing treatments are beset with issues such as reduced efficacy, toxicity, drug resistance, and compliance issues. This review examines vitamin C (ascorbic acid) as an adjunctive therapy to enhance the efficacy of current antiparasitic drugs based on available preclinical evidence. A comprehensive literature analysis reveals vitamin C’s antioxidant, immunomodulatory, and synergistic activities. It has been evidenced to modulate oxidative stress, enhance drug bioavailability, and bolster host immunity. When co-administered with traditional drugs, vitamin C demonstrated a 30-60% reduction in parasitic burdens, improved survival rates by 15-25%, and reduced organ damage in experimental models. Specific benefits included enhanced macrophage activity in leishmaniasis models, 40-50% reduction in cardiac inflammatory markers in Chagas disease, and improved parasite clearance rates in malaria studies. Its affordability and accessibility make it feasible for implementation in endemic areas. Vitamin C shows considerable promise as an adjunct therapy in NTDs. However, clinical trials are urgently required to establish human efficacy, optimize dosing regimens, and validate safety profiles observed in preclinical studies.