| Pharmaceutical Applications | C. longa is a golden herb consisting of many medicinal properties and is an effective source of treatment for various diseases since ancient times (Chaturvedi 2009; Zhang et al. 2012). This perennial plant is a member of the family Zingiberaceae. The rhizomes are the source of yellow dye and spice, “turmeric.” The yellow-colored pigment in turmeric is curcumin. C. longa has exhibited anti-inflammatory activity in animal models, and curcumin is majorly responsible for that. Curcumin acts as an antioxidant agent because of its phenolic structure. This compound alters serum glutathione and peroxidase activity, reduces lipid peroxidation, and scavenges the reactive oxygen species. Curcumin is established as an antioxidant, antimicrobial, and anti-inflammatory agent and effective against inflammatory bowel disease, pancreatitis, arthritis, cough, and cold (Jurenka 2009). Though chemopreventive efficacy of turmeric is established in experimental systems, its mechanism of action is not fully elucidated in vivo. Garg et al. (2008) have investigated in detail the mechanism of turmeric-mediated chemoprevention in buccal pouch carcinogenesis in hamsters. Dietary turmeric (1%) led to decrease in tumor burden by causing a decrease in cell proliferation, enhanced apoptosis, decrease in inflammation, and aberrant expression of differentiation markers, the cytokeratins. These biomarkers are proving to be helpful in monitoring clinical trials and evaluating drug effect measurements.
The most significant role of curcumin is its anti-tumorigenic and chemopreventive role (Anand et al. 2008). Curcumin shows growth inhibitory effect on cell lines of various cancers like those of the large intestine and bone, leukemia, and oral malignant epithelium (Sharma et al. 2005). In different studies on the cell lines of various cancers, curcumin inhibited proliferation of cells and accumulated cells at G2/M cell cycle (Sharma et al. 2005). A study on turmeric and oral cancer has reported that curcumin taken either in diet or applied locally could significantly reduce DNA adducts (Ganjre et al. 2015). Curcumin effectively repaired the broken DNA strands in the peripheral cells (Gupta et al. 2013a, b). It also deactivates tobacco carcinogens (Chaturvedi 2009). The augmented effect of curcumin and green tea is also studied on oral carcinogenesis in hamsters. Green tea and curcumin treatment significantly decreased oral visible tumor incidence from 92% to 69% and that of squamous cell carcinoma from 77% to 42%. Also curcumin alone and along with green tea significantly inhibited angiogenesis in papilloma and squamous cell carcinoma (Li et al. 2002).
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