Capsicum from Spice to Medicine: A Treasure Trove of Bioactive Compounds and Biotechnological Applications

Abstract

Capsicum fruits occupy an unusual position between staple horticultural commodities, globally traded spices, natural colourants and sources of pharmacologically active molecules. This critical narrative review integrates evidence on domestication, phytochemical diversity, biosynthetic regulation, human pharmacology, formulation science and crop biotechnology to evaluate how far the genus has progressed from culinary use towards defensible medical and industrial applications. Literature was selected through transparent searches of accessible biomedical and scholarly sources, with emphasis on verified primary studies, controlled clinical evidence, recent genomic resources and methodologically informative reviews. Capsaicinoids, capsinoids, carotenoids, phenolics, vitamins and volatile metabolites vary substantially with species, cultivar, tissue, maturity, environment and processing, making ‘Capsicum’ an imprecise exposure unless chemotype and product matrix are specified. Molecular work has established core components of pungency and pigment pathways, while pan-genomes, integrated metabolomics and spatial imaging now reveal regulatory and tissue-level heterogeneity that bulk assays can obscure. The strongest therapeutic evidence concerns topical capsaicin for selected peripheral neuropathic pain conditions, where local delivery can provide clinically meaningful but generally modest benefit without systemic drug exposure. Claims for weight control, cardiovascular protection, cancer treatment and broad anti-inflammatory action remain less secure because human studies are short, heterogeneous or absent, and many mechanistic findings rely on concentrations that may not be achieved through ordinary dietary intake. Delivery systems can improve solubility, retention and tolerability, but formulation-specific evidence cannot be generalised automatically to foods or crude extracts. In parallel, genome editing, virus-mediated reagent delivery and synthetic biology offer routes to tailor pungency, disease resistance, colour and high-value metabolites, although genotype-dependent regeneration, product standardisation, scale-up and regulation remain limiting. Capsicum is therefore best regarded not as a single medicinal entity but as a diversified platform whose translation depends on precise chemical characterisation, indication-specific clinical testing and biotechnology linked to realistic production and safety criteria.