Curcumin is the active component of the ancient herb from southern Asia, Curcuma longa, also known as turmeric. In the 1970s, researchers began to scientifically prove the validity of the longstanding use of turmeric in traditional Indian Ayurvedic medicine. For centuries, turmeric has been used to treat a variety of diseases, including digestive disorders, skin diseases, arthritis, hepatic disorders, inflammations and cardiovascular disease. Accumulating studies of curcumin show that this bright-yellow-colored root has significant anti-inflammatory, antimicrobial, antioxidant, anticarcinogenic and more recently discovered antiviral properties.
Curcumin
Curcumin (diferuloylmethane) is the active chemical component isolated from the roots of turmeric plants, which are grown extensively throughout Asia. The root, called the rhizome, is used as a primary spice in curry powders and has a long history in Ayurvedic and Chinese medicine. Curcumin exerts its healing effects via a variety of mechanisms that protect cells against death. A review by Strimpakos and Sharma in "Antioxidants and Redox Signaling" describes clinical studies showing that curcumin is non-toxic, showing only minor gastrointestinal discomfort at high doses, and has direct anti-inflammatory, antioxidant, antibacterial and anticarcinogenic activities. Curcumin affects these diverse pathologic processes by modulating cellular signal transduction pathways controlling cell growth and death.
Mechanism of Action
Active research is being done on curcumin's anticancer and antiviral properties. As of September 2010, the U.S. National Library of Medicine at the National Institute of Health lists 3596 scientific research papers on curcumin. A variety of cancers arise by specific virus-mediated genetic disruption. In addition to its numerous protective properties, curcumin also inhibits viral replication and infectivity. However, at higher concentrations, curcumin and its bioconjugates become toxic to cells, predominantly by inducing a process of cell death called apoptosis. According to a study by Kuttan, et al., in "Advances in experimental medicine and biology," this cytotoxic activity of curcumin can be used to inhibit proliferating tumor cells. By inhibiting the movement of essential signaling proteins into the cell nucleus, curcumin decreases the expression of genes required for cell division. In cervical carcinoma, neuroblastoma, melanoma, and prostate cancer cells, curcumin is therefore able to inhibit tumor cells from proliferating and promotes their apoptotic death. Clinical trials of curcumin in patients with a variety of different cancers are underway.
Viral Targets
Curcumin exhibits antiviral activity against numerous viruses, including human papillomavirus virus (HPV), influenza virus, Hepatitis B virus (HBV), Hepatitis C virus (HCV), adenovirus, coxsackievirus and Herpes simplex 1 (HSV-1). As demonstrated by Divya, et al., in "Molecular Carcinogenesis," curcumin inhibits the expression of HPV proteins that are required for HPV-induced cervical carcinoma. In another study published in the "Journal of Neuroimmune Pharmacology," neuronal cells were protected by curcumin from infection by the Japanese encephalitis virus, a deadly infection that primarily affects children. This antiviral activity may be mediated by curcumin's ability to decrease reactive oxygen species, restore cell membrane integrity and inhibit apoptosis of the neuronal cells. Another mechanism of action of this multi-functional chemical, published in "FEBS Letters" in 2010, demonstrates the direct inhibition of HCV viral replication by curcumin. Curcumin may therefore be useful in the treatment of patients with highly prevalent viral hepatitis, cirrhosis and liver cancer. In clinical trials, curcumin, however, does not appear to be an effective agent against the human immunodeficiency virus (HIV).
Keep these potential antiviral effects in mind the next time you sprinkle turmeric in your curry.
References
- "Antioxidants and Redox Signaling"; Curcumin: preventive and therapeutic properties in laboratory studies and clinical trials; Strimpakos AS and Sharma RA; 2008
- "Advances in experimental medicine and biology"; Antitumor, anti-invasion, and antimetastatic effects of curcumin; Kuttan G, et al.; 2007
- "Molecular Carcinogenesis"; Antitumor action of curcumin in human papillomavirus associated cells involves downregulation of viral oncogenes, prevention of NFkB and AP-1 translocation, and modulation of apoptosis; Divya CS and Pillai MR; 2006
- "Journal of Neuroimmune Pharmacology"; Curcumin protects neuronal cells from Japanese encephalitis virus-mediated cell death and also inhibits infective viral particle formation by dysregulation of ubiquitin-proteasome system; Dutta K, et al.; 2009
- "FEBS Letters"; Curcumin inhibits hepatits C virus replication via suppressing the Akt-SREBP-1 pathway; Kim K, et al.; 2010
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