Curcumin and Its Nanoformulations: Emerging Strategies for the Prevention and Management of Allergic Diseases

Allergic diseases are a heavy clinical and socioeconomic burden to human society. Dysregulated immune responses, especially a Th2 cytokine response and IgE-mediated hyperinflammation, are the main factors of the cascade of cellular and molecular events that underlie the immunopathogenesis of allergic diseases. The traditional antiallergic treatment is restricted today because of a wide variety of adverse effects (skin atrophy, growth retardation in children, hypertension, osteoporosis, and tachycardia). Thus, preclinical research should find other interventions that have fewer side effects and optimize the effectiveness of the treatment plan. Curcumin is a polytropic bioactive polyphenol derived from the rhizome of turmeric plant (strong anti-inflammatory, antioxidant, and immunomodulatory properties). The low water solubility, chemical instability, and rapid systemic metabolism have, however, limited its clinical use. Reportedly, nanotechnology has attempted to improve the pharmacokinetic and therapeutic targeting of nanocurcumin formulations using a number of methods. Therefore, this paper is a review of the immunopharmacological prospects of curcumin and nanocurcumin in allergic diseases, including preclinical and clinical evidence. The current review paper reviews the effects of curcumin in the inhibition of Th2 responses. Moreover, it has explored the Th1/Th2 balance, mast cell degranulation inhibition, decreasing proinflammatory mediators, and immune modulation. Conversely, it has recommended nanotechnological methods to enhance the solubility, cellular internalization, and release characteristics of nanocurcumin preparations to increase its efficacy. Lastly, the review gives future research directions by ranking limitations of the existing literature (methodological diversity and difficulties in applying the results to a clinical setting).