Antioxidants and Cancer: Molecular Mechanisms. In: Armstrong D, editor. Free Radicals in Diagnostic Medicine. Boston: Springer US; 1994. pp. 215-39. [DOI: 10.1007/978-1-4615-1833-4_16]

Oriental Hornet (Vespa orientalis) Larval Extracts Induce Antiproliferative, Antioxidant, Anti-Inflammatory, and Anti-Migratory Effects on MCF7 Cells

The use of insects as a feasible and useful natural product resource is a novel and promising option in alternative medicine. Several components from insects and their larvae have been found to inhibit molecular pathways in different stages of cancer. This study aimed to analyze the effect of aqueous and alcoholic extracts of Vespa orientalis larvae on breast cancer MCF7 cells and investigate the underlying mechanisms. Our results showed that individual treatment with 5% aqueous or alcoholic larval extract inhibited MCF7 proliferation but had no cytotoxic effect on normal Vero cells. The anticancer effect was mediated through (1) induction of apoptosis, as indicated by increased expression of apoptotic genes (Bax, caspase3, and p53) and decreased expression of the anti-apoptotic gene Bcl2; (2) suppression of intracellular reactive oxygen species; (3) elevation of antioxidant enzymes (CAT, SOD, and GPx) and upregulation of the antioxidant regulator Nrf2 and its downstream target HO-1; (4) inhibition of migration as revealed by in vitro wound healing assay and downregulation of the migration-related gene MMP9 and upregulation of the anti-migratory gene TIMP1; and (5) downregulation of inflammation-related genes (NFκB and IL8). The aqueous extract exhibited the best anticancer effect with higher antioxidant activities but lower anti-inflammatory properties than the alcoholic extract. HPLC analysis revealed the presence of several flavonoids and phenolic compounds with highest concentrations for resveratrol and naringenin in aqueous extract and rosmarinic acid in alcoholic extract. This is the first report to explain the intracellular pathway by which flavonoids and phenolic compounds-rich extracts of Vespa orientalis larvae could induce MCF7 cell viability loss through the initiation of apoptosis, activation of antioxidants, and inhibition of migration and inflammation. Therefore, these extracts could be used as adjuvants for anticancer drugs and as antioxidant and anti-inflammatory agents.

An estimation and evaluation of total antioxidant capacity of saliva in children with severe early childhood caries

BACKGROUND. The available evidence implicating the involvement of oxidative stress in the caries process suggests that local antioxidant status may be of importance in determining the susceptibility to the caries process. AIM. The aim of this study was to estimate the total antioxidant capacity (TAC) in unstimulated saliva of healthy children with and without severe early childhood caries (S-ECC) and to correlate the individual TAC level with dmft (d = decayed, m = missing, f = filled, t = teeth) score and age. MATERIAL AND METHODS. The TAC of saliva was investigated in 100 healthy children in the age range of 3-5 years divided in two groups, control and study group based on the absence or presence of caries, respectively. The antioxidant capacity of saliva was estimated by an adaptation of ABTS [2, 2'-Azino-di-(3-ethylbenzthiazoline sulphonate)] assay. RESULTS. The mean TAC level in the saliva of the children in study group was found to be significantly increased (P < 0.001), and a significantly linear regression was seen between the TAC and dmft score (P < 0.001) whereas it was insignificant between the TAC and age (P = 0.078). CONCLUSION. The results indicated that TAC of saliva increased significantly in children with S-ECC and increasing prevalence of dental caries predisposes to the increase in TAC of saliva.

Total antioxidant levels of saliva in children related to caries, age, and gender

AIM

The purpose of this study was to evaluate the relationship between the physicochemical properties of saliva such as flow rate, buffering capacity, pH, calcium level, total protein, total antioxidant status, and dental caries, age, and gender.

MATERIAL AND METHODS

The antioxidant activity of saliva was investigated in 80 healthy children aged 7-15 years. They were divided into subgroups according to gender, age (7-10 years and 11-15 years), and caries activity (caries active=CA and caries free=CF). Unstimulated saliva samples were collected from all groups. Flow rates were determined, and samples analysed for pH, buffer capacity, calcium, total proteins, and total antioxidant status. Salivary total antioxidant activity (TAA) was estimated by an adaptation of the ABTS (2,2-azino-di (3-ethylbenzthiazoline-6-sulphonate)) assay.

RESULTS

The results indicated that in general, although there was no linear association between salivary flow rate pH and buffering capacity values obtained from different groups, salivary calcium concentration values were found to be higher in caries free groups. Total protein and total antioxidant values were higher in caries active groups except those in the 11- to 15-year-old girls group.

CONCLUSION

In general, total protein and total antioxidant insaliva were increased with caries activity. Calcium concentrations in saliva were higher in caries-free children. In addition, calcium concentration increased with age. Thus, it can be concluded that a linear association exists between calcium concentration age and caries activity. More clinical and laboratory studies are needed to determine the exact relationship between the physicochemical properties of saliva such as flow rate, buffering capacity, pH, calcium level, total protein, total antioxidant status, and dental caries, age, and gender.

Combined efficacy of tamoxifen and coenzyme Q10 on the status of lipid peroxidation and antioxidants in DMBA induced breast cancer

An increasing amount of experimental and epidemiological evidence implicates the involvement of oxygen derived radicals in the pathogenesis of cancer development. It is well known that chemical carcinogenesis is multistage process. Free radicals arefound to be involved in both initiation and promotion of multistage carcinogenesis. Tamoxifen (TAM) is a potent antioxidant and a non-steroidal antiestrogen drug most used in the chemotherapy and chemoprevention of breast cancer. Besides its anticarcinogenic potential, it also produces some adverse toxic side effects, while taken for a long time. In order to minimise the side effects and to improve the antioxidant efficacy of tamoxifen, coenzyme Q10 (CoQ10) was added. Hence the present study was designed to investigate the combined efficacy of TAM along with CoQ10 in 7, 12 dimethyl benz(a)anthracene (DMBA) induced peroxidative damage in rat mammary carcinoma. The experimental setup comprised of one control and five experimental groups and it was carried out in adult female Sprague-Dawley rats. Mammary carcinoma was induced by oral administration of DMBA (25 mg kg(-1) body wt) and the treatment was started by the oral administration of TAM (10 mg kg(-1) body wt day(-1)) and CoQ10 (40 mg kg(-1) body wt day(-1)) dissolved in olive oil and continued for 28 days. Rats induced with DMBA showed a decline in the thiol capacity of the cell accompanied by high malondialdehyde content levels along with lowered activities of antioxidant status (superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione). In contrast, glutathione metabolising enzymes (glutathione reductase, glucose-6-phosphate dehydrogenase and glutathione-S-transferase) were increased significantly in chemically induced carcinoma bearing rats. Administration of TAM along with CoQ10 restored the activities to a significant level thereby preventing cancer cell proliferation. This study highlights the increased antioxidant enzyme activities in relation to the susceptibility of cells to carcinogenic agents and the response of tumour cells to the chemotherapeutic agents.

Coenzyme Q10 concentrations and antioxidant status in tissues of breast cancer patients

OBJECTIVES

An increasing amount of experimental and epidemiological evidence implicates the involvement of oxygen derived radicals in the pathogenesis of cancer development. Oxygen derived radicals are able to cause damage to membranes, mitochondria, and macromolecules including proteins, lipids and DNA. Accumulation of DNA damages has been suggested to contribute to carcinogenesis. It would, therefore, be advantageous to pinpoint the effects of oxygen derived radicals in cancer development.

DESIGN AND METHODS

In the present study, we investigated the relationship between oxidative stress and breast cancer development in tissue level. Breast cancer is the most common malignant disease in Western women. Twenty-one breast cancer patients, who underwent radical mastectomy and diagnosed with infiltrative ductal carcinoma, were used in the study. We determined coenzyme Q10 (Q) concentrations, antioxidant enzyme activities (mitochondrial and total superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase), and malondialdehyde (MDA) levels in tumor and surrounding tumor-free tissues.

RESULTS

Q concentrations in tumor tissues significantly decreased as compared to the surrounding normal tissues (p < 0.001). Higher MDA levels were observed in tumor tissues than noncancerous tissues (p < 0.001). The activities of MnSOD, total SOD, GSH-Px and catalase in tumor tissues significantly increased (p < 0.001) compared to the controls.

CONCLUSIONS

These findings may support that reactive oxygen species increased in malignant cells, and may cause overexpression of antioxidant enzymes and the consumption of coenzyme Q10. Increased antioxidant enzyme activities may be related with the susceptibility of cells to carcinogenic agents and the response of tumor cells to the chemotherapeutic agents. Administration of coenzyme Q10 by nutrition may induce the protective effect of coenzyme Q10 on breast tissue.

Antioxidants in the prevention of renal disease

In view of the role of oxidative processes in inflicting damage that leads to glomerulosclerosis and renal medullary interstitial fibrosis, more attention could be paid to the use of antioxidant food constituents and the usage of drugs with recognized antioxidant potential. In any case atherosclerosis is an important component of chronic renal diseases. There is a wide choice of foods and drugs that could confer benefit. Supplementation with vitamins E and C, use of soy protein diets and drinking green tea could be sufficient to confer remarkable improvements.

Whole-grain consumption and chronic disease: protective mechanisms

Dietary guidance recommends consumption of whole grains to reduce the risk of chronic diseases including cancer and cardiovascular disease. Epidemiologic studies support the belief that whole grains are protective against cancers, especially gastrointestinal cancers such as gastric and colonic, and cardiovascular disease. Components in whole grains that may be protective are diverse and include compounds that affect the gut environment, i.e., dietary fiber, resistant starch, and other undigestible compounds in whole grains, compounds that function as antioxidants such as trace minerals and phenolic compounds, and compounds that are phytoestrogens with potential hormonal effects. Many of the protective compounds in whole grains are also in fruits and vegetables, but some plant compounds are more concentrated in whole grains, such as phenolic compounds including ferulic and caffeic acid. Other potential mechanistic effects of whole grains include binding of carcinogens and modulation of glycemic index. Clearly, the range of protective substances in whole grains is impressive, and advice to consume additional whole grains is justifiable.