Curcuminoids

Curcuminoids are a class of natural polyphenolic compounds found in the rhizomes of turmeric, Curcuma longa. The best known members are curcumin (diferuloylmethane), demethoxycurcumin, and bisdemethoxycurcumin. Together they contribute to turmeric’s yellow color and have been studied for anti-inflammatory, antioxidant, and potential anticancer activities. Curcuminoids are diarylheptanoids with methoxy- and hydroxy-substituted phenyl rings connected by a seven-carbon chain.

Source and uses: Turmeric rhizomes contain curcuminoids in modest amounts and are widely used as a culinary spice, a natural dye, and in traditional medicine. Curcuminoids are also marketed as dietary supplements. In the food industry, turmeric extract and curcuminoids are used as color additives in some jurisdictions (often labeled as curcumin or turmeric extract).

Chemistry and properties: Curcuminoids are relatively hydrophobic and have limited water solubility, with higher solubility in organic solvents such as ethanol or DMSO. They are sensitive to light and heat and can degrade under alkaline conditions. They exhibit keto–enol tautomerism in solution and are typically present as a mixture of forms.

Biology and pharmacokinetics: In vitro and in animal studies, curcuminoids show anti-inflammatory and antioxidant effects and can modulate signaling pathways such as NF-κB and COX-2. In humans, bioavailability is generally low due to poor absorption, rapid metabolism, and systemic elimination, with most detectable forms being glucuronide or sulfate conjugates. Formulations with adjuvants (for example, piperine) or specialized delivery systems can enhance exposure.

Safety and regulation: Curcuminoids are considered safe in amounts typical for food use. High-dose supplementation can cause gastrointestinal symptoms in some individuals and may interact with certain medications. They are not approved as drugs for disease treatment in most jurisdictions.