Antioxidant vitamins and chemoprevention

Interdependence of antioxidants and micronutrients in oral cancer and potentially malignant oral disorders: a serum and saliva study

OBJECTIVE

In our previous studies we have evaluated the role of antioxidants and trace elements in potentially malignant disorders and cancers of the oral cavity, taking into consideration the importance of antioxidants as biomarkers in cancer detection. We felt that other than evaluation, the correlation and interdependence that existed among antioxidants and trace elements require further evaluation in order to develop a better understanding.

MATERIALS AND METHODS

Serum and salivary zinc, glutathione, and superoxide dismutase levels were evaluated in 65 healthy controls, 115 subjects with potentially malignant oral disorders, and 50 subjects with oral squamous cell carcinoma, using the atom absorption photometry, [5, 5-Dithiobis (2 nitrobenzoic acid)], and nitroblue tetrazolium methods, respectively.

RESULTS

Serum zinc and serum glutathione showed significant positive correlation (r=0.76, P=0.01). Similarly, salivary glutathione and salivary zinc levels had a positive correlation (r=0.68, P=0.01). Serum superoxide dismutase showed a strong positive correlation with serum zinc (r=0.64, P=0.01). Similarly, there was a moderate positive correlation between salivary superoxide dismutase and salivary zinc (r=0.67, P=0.01).

CONCLUSION

Our findings showed that trace elements and antioxidants exhibited interdependence in serum, as well as in saliva, in both physiologic and pathologic states such as oral cancer.

Oxidative stress--implications, source and its prevention

Oxidative stress has been a major predicament of present day living. It has been the product of imbalance between the processes involved in free radical generation and their neutralization by enzymatic and non-enzymatic defence mechanisms. The oxidative stress has been contributed by numerous factors including heavy metals, organic compound-rich industrial effluents, air pollutants and changing lifestyle pattern focussing mainly on alcohol consumption, dietary habits, sun exposure, nuclear emissions, etc. The most common outcome of oxidative stress is the increased damage of lipid, DNA and proteins that resulted in the development of different pathologies. Among these pathologies, cancer is the most devastating and linked to multiple mutations arising due to oxidative DNA and protein damage that ultimately affect the integrity of the genome. The chemopreventive agents particularly nutraceuticals are found to be effective in reducing cancer incidences as these components have immense antioxidative, antimutagenic and antiproliferative potentials and are an important part of our dietary components. These secondary metabolites, due to their unique chemical structure, facilitate cell-to-cell communication, repair DNA damage by the downregulation of transcription factors and inhibit the activity of protein kinases and cytochrome P450-dependent mixed function oxidases. These phytochemicals, therefore, are most appropriate in combating oxidative stress-related disorders due to their tendency to exert better protective effect without having any distinct side effect.

Hyperhomocysteinemia and cardiovascular disease: The nutritional perspectives

Several members of the vitamin B-complex family are known to participate in the normal metabolism of homocysteine (Hcy). Leaving aside the genetic determinants of hyperhomocysteinemia (HHC), the deficiencies of these vitamins can also result in HHC. The situation of sustained and long standing HHC is likely to be prevalent in population groups with low/average socio-economic status, geriatric population and alcohol abusers. If not corrected by supplementation, these population groups certainly are more vulnerable to develop atherosclerosis (AS) and subsequently, cardiovascular disease (CVD). Hyperhomocysteinemia per se and/or HHC-induced oxidative stress result(s) in chronic chemical endothelial injury/dysfunction, smooth muscle proliferation, prothrombotic state and oxidation of low density lipoproteins (LDL) leading to diverse cardiovascular complications. In the first decade of the new millennium, major research efforts would be directed towards understanding the basic mechanism of HHC-induced oxidative stress and the pathophysiology of HHC-induced CVD, culminating in the evolution of hitherto unknown therapeutic strategies such as nutriceuticals and oxidant-antidotes.