Curcumin is a polyphenol group compound with a chemical structure similar to ferulic acid. Curcumin is a substance contained in java ginger and turmeric. Hereditary, java ginger and turmeric has been used by Asians for cooking, medicine, and even cosmetics.
Cancer is a group of diseases that have more than 100 types. Cancer is characterized by uncontrolled growth of cells, invasion of local tissues, and metastases to a place away from tumor cells. This disease is ranked second after heart disease and cause many deaths.
Prevention or treatment of cancer became increasingly important as the incidence rate is quite high. Some attempts at cancer treatment have been carried out intensively covering physical medicine, surgery and treatment with chemotherapy. Until now a truly effective cancer treatment has not been found. This is because the low selectivity of cancer treatment used or not yet know clearly the carcinogenic process.
Curcumin is the largest part of yellow pigment found in the turmeric rhizome (Curcuma longa) which has various biological activities such as antioxidants, anti-inflammatory, and antineoplastic. By Asians, like India and Indonesia, the yellow dye from the curcuma is often used as a food or medicinal herb and does not cause any harmful toxic effects.
Over the past two decades a lot of research on curcumin as an active ingredient to overcome some diseases. Among these studies reported on the effects of curcumin as an antioxidant. The mechanism of curcumin as an anticancer is a very complex problem. Antioxidant activity and curcumin are well documented and indicate as an inhibitor of cancer carcinogenesis process.
Its activity as an anti-inflammatory, ie as a cyclooxygenase enzyme inhibitor, has been linked to activity as an anticancer, especially colon cancer. Other studies have shown that curcumin is also active to inhibit the process of carcinogenesis at the initiation stage. Curcumin also has the effect of spurring the apoptosis process, a natural process of cell death to support the cell integrity as a whole. Other studies have shown that curcumin is able to inhibit cell proliferation and induce cell cycle in colon adenocarcinoma without prostaglandin. Curcumin is also able to inhibit the growth of breast cancer cells without expression of estrogen receptor.
Curcumin as an anti-cancer
Some aspects of curcumin biology have been widely reported in various literatures. Biological aspects of curcumin are widely developed pharmacological performance as anti-inflammatory, antihepatotoxic, and anti-cancer. As an anti-cancer, the curcumin action is usually associated with its activity as an antidote to free radicals, antioxidants, anti-proliferation, anti-inflammatory.
1. Curcumin as an antioxidant
Curcumin has been known to have antioxidant activity. In addition, curcumin also acts as a catalyst in the hydroxyl radicals formation. This ability makes curcumin able to act as radical scavenger to metabolites between carcinogen compounds, thereby reducing the incidence of cancer. The chemopreventive properties of curcumin because it has the ability to inhibit the P450 cytochrome and glutathione enzymes. However, curcumin is an antioxidant to counteract free radicals.
2. Curcumin as cyclooxygenase inhibitors
Until now in the body there are two types of COX in the form of isoform, COX-1 and COX-2. Both have the same activity as a prostanoid synthesis catalyst of arachidonic acid. The enzyme cyclooxygenase type 1 constitutively expressed significantly by almost all mammals at a constant level and will only increase slightly when there is stimulation for growth factors or during differentiation, whereas COX-2 is expressed only by a part of the network in a low-level. The enzyme cyclooxygenase type 2 usually be expressed more for their mitogen stimulation, cytokines, and tumor promoters that can be caused by the presence of cell damage or other factors.
Inhibition of cyclooxygenase (COX) enzyme, the prostanoid overproduction can be prevented and will reduce the effects of inflammation. In cancer cells, it will reduce cell proliferation and prevent apoptosis. In this path the apoptotic process is driven by the accumulation of arachidonic acid due to inhibition of the cyclooxygenase enzyme. The arachidonic acid accumulation activates the sphingomyelinase enzyme that catalyzes the ceramide formation from sphingomyelin. The ceramide is a positive booster apoptosis process. The curcumin mechanism is not limited to COX inhibition, but also inhibits lipoxesigenase (LOX) enzyme activity, thereby reducing the LOX product.
3. Curcumin as anti-proliferation
Curcumin is able to inhibit cell proliferation, so it is called anti-proliferation compound. In mammals, cell proliferation is regulated by a set of proteins produced by the genes regulating tumor known as oncogenes, in normal circumstances is called a proto-oncogene. While there is also a tumor suppressor gene, a type of inhibiting cell proliferation gene as well. Both types of genes work in harmony to regulate cell proliferation damage or gene mutation is at risk for cancer or excessive cell proliferation.
Curcumin can inhibit cell proliferation through various mechanisms. Curcumin is reported to inhibit the activity of protein kinase C. This protein has a role in cell division. Curcumin exhibits anti-proliferative effects in colon adenocarcinoma cell lines. Anti-proliferative curcumin is caused due to changes in cell cycle that are independent of prostaglandin synthesis. Curcumin is also able to inhibit the proliferation of breast cancer cells through other channels. To inhibit breast cancer cell proliferation will be more effective when done together with isoflavonoid.
4. Curcumin as a trigger apoptosis
Apoptosis is a suicide program of a cell. This program has an important role to maintain cell proliferation homeostasis. One important role is to limit the cells proliferation that are not needed and can cause cancer. Curcumin can stimulate the process of apoptosis in several ways.
A new perspective on curcumin activity as an anticancer linked to the curcumin mechanism, which has provided a more comprehensive overview of curcumin performance as an anticancer. In the future, research on curcumin as an anticancer will make it more clear to elucidate mechanisms at the molecular level. By knowing the mechanism of curcumin as an anticancer will open the possibility of curcumin compounds to be developed as cancer treatment in the future.