Turmeric is the most common spice in India, as explained in Ayurveda for treating inflammatory diseases. Curcumin and curcuminoids are the active compounds of turmeric considered effective therapy. The dietary supplements containing curcumin are popular, and more antioxidant and anti-inflammatory curcumin nutritional supplements are available (Menon & Sudheer, 2007). Inflammation is the adaptive response caused by harmful stimuli and conditions due to infection and tissue damage, resulting in complexities in physiological and pathological processes. The inflammation in any disease worsens the disease severity, enhancing the inflammation, possessing challenges in the treatment. Hence, there is a need for the compounds to have anti-inflammatory effects showing direction for the therapeutic drugs. The anti-inflammatory activity of curcumin has attracted several researchers’ interests. It is considered one of the natural compounds with the most significant potential in the treatment of diseases.
Hence, the anti-inflammatory and antioxidant mechanisms, along with some other therapeutic effects of curcumin, are considered the most important hotspot. Antioxidant and anti-inflammatory properties are the two primary mechanisms that explain the impact of curcumin on different conditions.
Anti-inflammatory mechanism of curcumin
The inflammatory pathway consists of four significant parts involving inducers, sensors, mediators and effectors. The anti-inflammatory effects of drugs affect the mechanism of receptors and signalling pathways, regulation of the response of target tissues to inflammatory mediators, reversing the impact of the medium on the target tissue and production of anti-inflammatory mediators. Curcumin evolves anti-inflammatory effects by regulating signalling pathways and inhibiting the production of mediators.
Curcumin binds to Toll-like receptors (TLRs) and regulates downstream nuclear factor kappa-B (NF-κB), Mitogen-activated protein kinases (MAPK), Activator Protein 1(AP-1) and other signalling pathways. It results in the regulation of inflammatory mediators and treating inflammatory diseases. Curcumin can decrease the level of proinflammatory mediators in the case of inflammatory cells. The regulatory effect of curcumin on immune cells shows efficacy in treating inflammatory diseases. Also, oxidative stress is closely associated with the inflammatory process.
Anti-oxidant mechanism of curcumin
The chemical structure of curcumin, along with hydroxyl and methoxy groups, is associated with different properties, mainly concerned with antioxidant, antimicrobial, anti-inflammatory, anti-angiogenic, and antimutagenic (Kocaadam & Şanlier, 2017). Curcumin inhibits inflammatory cell proliferation and angiogenesis due to its capability of interacting with different target molecules. These mechanisms are concerned with the regulation of proinflammatory cytokines, nitric oxide synthase (iNOS) enzymes, cyclooxygenase-2 (COX-2), lipoxygenase, xanthine oxidase, and reduction in malondialdehyde (MDA). The effectiveness of antioxidant properties of curcumin minimizes the effects of oxidative stress. It interacts with various molecular mechanisms that, in turn, result in reducing the level of oxidative stress while chelating heavy metals and regulating the activity of many enzymes.
Complexities in the interaction of inflammation and oxidative stress have contributed to implicating different therapeutic roles of curcumin. Hence, the information on curcumin’s anti-inflammatory and antioxidant functions is explained to utilize curcumin as a therapeutic agent in future therapeutic regimes to enhance the efficacy of the treatment and reduce the adverse effects of synthetic chemical drugs.
- Kocaadam, B., & Şanlier, N. (2017). Curcumin, an active component of turmeric (Curcuma longa), and its effects on health. Critical reviews in food science and nutrition, 57(13), 2889-2895. https://doi.org/10.1080/10408398.2015.1077195
- Menon, V. P., & Sudheer, A. R. (2007). Antioxidant and anti-inflammatory properties of curcumin. The molecular targets and therapeutic uses of curcumin in health and disease, 105-125. https://doi.org/10.1007/978-0-387-46401-5_3