Previous studies have highlighted the necessity of antioxidants and anti-inflammatory drugs in the defense against cancer. Cancer and most other chronic diseases are caused because of oxidative damage and inflammation. Curcumin, a principal component of the spice turmeric, has antioxidant and anti-inflammatory properties and is a potential option for the treatment of cancer. This review illustrates from various studies the potential uses of curcumin and the action mechanism behind its efficacy for the treatment and prevention of cancer. Curcumin, having a low bioavailability (or ability of the body to use the components) and solubility, has not achieved positive outcomes in many clinical trials that tested its use as a therapeutic agent. This review also discusses a few ways in which these problems can be overcome.
Polyphenols are chemical compounds that help to maintain good health and prevent most diseases. Coffee, green tea, chocolate, red wine, olive oil and nuts are good sources of polyphenols. Turmeric, which is conventionally used as a food spice, is a good source of polyphenols that possess antioxidant and anti-inflammatory properties. The U.S. Food and Drug Administration (FDA) has approved various turmeric products because of their safety. Curcumin is the principal polyphenol in turmeric and is available as over-the-counter supplements in countries all over the world. It gives turmeric its yellow color. Curcumin has been used for long in traditional treatment remedies, and various clinical trials have proved its safety. It has been used to supplement many other commonly used chemotherapeutic agents. This review was conducted to compare and evaluate the results from earlier studies on the efficacy of curcumin and to highlight possible modifications in the molecule that can enhance its bioavailability and solubility, thus converting it into a suitable therapeutic agent.
* Various studies and clinical trials conducted earlier were analyzed to evaluate the use of curcumin and its effects on inflammation and cancer.
* The studies were reviewed and discussed based on the toxicity of curcumin, its effects on inflammation, its effects on various cancers, its bioavailability, and modern methods of drug delivery for enhancing its efficacy.
* The daily acceptable limit for curcumin intake is between 0.1 and 3 mg per 1 kg of body weight. In one of the clinical trials reviewed, oral doses up to 3.5 g/kg body weight for three months caused no adverse effects.
* Curcumin, taken along with piperine, a component of black pepper, helps increase its bioavailability and absorption, thereby increasing the levels of curcumin in blood. Curcumin was found to inhibit the oxidizing molecules that cause oxidative damage and thus, it possesses antioxidant activity. It also showed anti-inflammatory effects by inhibiting certain molecules that are responsible for causing inflammation.
* Curcumin was found to delay graft rejection in some studies, and can therefore be beneficial in organ transplant. In another study, curcumin was shown to reduce the size of oral cancers.
* Modern drug delivery methods, such as those involving the use of lipid envelopes or nanoparticles, were shown to enhance the stability of curcumin and increase its uptake by blood.
A few of the studies that were reviewed had missing data, while some studies did not include control groups in their clinical trials. Although newer methods of delivery of curcumin have been reported, they have not yet been deployed for clinical evaluation. Thus, the poor bioavailability of the compound is yet to be tackled in order to make it a suitable candidate for use in therapeutics.
Owing to the beneficial effects of curcumin, especially as an antioxidant, it can prove to be a good adjunct treatment modality for cancers. From all the studies summarized in this review, it is found that curcumin is useful in wound healing; it functions as an antimicrobial, antiviral, antifungal, and an anti-inflammatory agent. The poor bioavailability and absorption of curcumin have been dealt with by using lipid encapsulation, polymeric coating, and nanoscale delivery methods. These newer methods of delivery increase its stability and bioavailability. Recent research suggests that naturally occurring chemicals from plants have synergistic effects, and can be used along with the previously available anti-cancer medications to achieve optimal effects. Thus, the choice of curcumin as an anti-cancer adjuvant seems very promising.
For More Information:
Curcumin: An Anti-inflammatory Molecule from a Curry Spice on the Path to Cancer Treatment
Publication Journal: Molecules, June 2011
By Purusotam Basnet; Natasa Skalko-Basnet; University of Tromsø, Tromsø, Norway
*FYI Living Lab Reports Are Summaries of the Original Research.