Curcumin is a bright yellow chemical produced by plants of the Curcuma longa species. It is the principal curcuminoid of turmeric, a member of the ginger family, Zingiberaceae. It is sold as an herbal supplement, cosmetics ingredient, food flavoring, and is commercially isolated as a mixture of curcuminoids or as an enriched crystalline diferuloylmethane (CAS 458-37-7) with molecular formula C21H20O6 and molecular weight 368.38 g mol^-1. The compound has low aqueous solubility, is soluble in ethanol, acetone and DMSO, and shows a characteristic UV-vis absorbance near 420 to 425 nm in organic solvents; it is commonly standardized to 95 percent total curcuminoids for analytical and formulation use. Typical production methods employ solvent extraction, supercritical CO2 extraction, or chromatographic purification, and finished material is characterized by HPLC, UV spectroscopy and melting point evaluation.
Commercial curcumin preparations are mixtures in which curcumin I (diferuloylmethane), demethoxycurcumin (curcumin II) and bisdemethoxycurcumin (curcumin III) are the principal related compounds; a typical 95 percent curcuminoid extract will contain approximately 70 to 80 percent curcumin I, 15 to 25 percent demethoxycurcumin and 2 to 7 percent bisdemethoxycurcumin, with remaining components and noncurcuminoid residues below about 5 percent. Typical quality specifications for finished material include loss on drying or moisture less than or equal to 5 percent, total ash under 0.5 percent, residual solvents within ICH class limits (for example ethanol as class 3 solvent), and heavy metals commonly controlled to lead less than 10 parts per million, arsenic less than 3 ppm, cadmium less than 1 ppm and mercury less than 0.1 ppm; degradation markers such as vanillin or ferulic acid are generally present at trace levels under one percent, and microbial limits are set to pharmacopeial or food grade thresholds.
Curcumin is one of several active curcuminoids found in turmeric root; turmeric is the whole rhizome that contains volatile oils, starches and about 2 to 9 percent curcuminoids by weight, so curcumin is a constituent of turmeric but not the whole plant material.
Curcumin interacts with multiple biochemical pathways in vitro and in vivo, displaying antioxidant and antiinflammatory activity in laboratory studies; in humans it is studied for effects on inflammatory markers, joint comfort and digestive tolerance, but clinical outcomes depend on dose, formulation and bioavailability.
Limitations include very low oral bioavailability in unformulated material, variable absorption between individuals, potential for gastrointestinal upset at high doses, possible interactions with drugs that affect liver enzymes or blood clotting, and the need for standardized, contaminant tested material to ensure safety.
Curcumin shows anticancer activity in cell culture and animal models through multiple mechanisms, but evidence from controlled human clinical trials is not conclusive; it is considered an investigational compound in oncology contexts and should not replace standard cancer therapies.
