Dengue Fever Management: Pathophysiology, Therapeutic Challenges, Potential of Carica Papaya Leaf, and Advanced Drug Delivery Systems

Dengue is a major mosquito-borne viral disease with a broad clinical spectrum ranging from self-limiting febrile illness to severe dengue associated with plasma leakage, thrombocytopenia, hemorrhage, shock, and multi-organ dysfunction. Despite advances in diagnosis and supportive management, the lack of a widely effective specific antiviral therapy remains a major therapeutic challenge. Consequently, increasing attention has been directed toward medicinal plants and bioactive phytoconstituents as potential complementary therapeutic approaches. Among these, Carica papaya L. has attracted considerable interest because of its reported platelet-supportive, antioxidant, anti-inflammatory, immunomodulatory, and potential antiviral properties. However, variability in plant material, phytochemical composition, extraction procedures, dose, stability, and bioavailability limits the reproducibility and pharmaceutical translation of conventional C. papaya preparations. This review summarizes the current understanding of dengue virology, pathophysiology, clinical progression, diagnosis, therapeutic management, and major unmet therapeutic needs, with particular emphasis on the pharmacological potential and evidence supporting C. papaya leaf in dengue. The review further discusses the phytochemical basis, proposed molecular mechanisms, preclinical and clinical evidence, safety considerations, and limitations of conventional preparations. In addition, advanced drug-delivery systems, including liposomes, phytosomes, nanoemulsions, lipid nanoparticles, and microemulsions, are evaluated for their potential to improve the solubility, stability, bioavailability, and formulation consistency of herbal therapeutics. Particular emphasis is placed on microemulsion-based delivery as a rational strategy for improving the pharmaceutical performance of C. papaya leaf extract. Finally, current research gaps and future perspectives involving extract standardization, mechanistic validation, pharmacokinetic studies, formulation optimization, toxicological evaluation, and well-designed clinical trials are highlighted. Integrating standardized phytochemistry with advanced drug-delivery technologies may provide a promising pathway for the development of reproducible C. papaya-based therapeutic formulations for dengue management.