Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

Reactive oxygen species (ROS) are common by-products of normal aerobic cellular metabolism and play important physiological roles in intracellular cell signaling and homeostasis. The human body is equipped with antioxidant systems to regulate the levels of these free radicals and maintain proper physiological function. However, a condition known as oxidative stress (OS) occurs, when ROS overwhelm the body's ability to readily detoxify them. Excessive amounts of free radicals generated under OS conditions cause oxidative damage to proteins, lipids, and nucleic acids, severely compromising cell health and contributing to disease development, including cancer. Biomarkers of OS can therefore be exploited as important tools in the assessment of disease status in humans. In the present review, we discuss different approaches used for the evaluation of OS in clinical samples. The described methods are limited in their ability to reflect on OS only partially, revealing the need of more integrative approaches examining both pro- and antioxidant reactions with higher sensitivity to physiological/pathological alternations. We also provide an overview of recent findings of OS in patients with different types of cancer. Identification of OS biomarkers in clinical samples of cancer patients and defining their roles in carcinogenesis hold great promise in promoting the development of targeted therapeutic approaches and diagnostic strategies assessing disease status. However, considerable data variability across laboratories makes it difficult to draw general conclusions on the significance of these OS biomarkers. To our knowledge, no adequate comparison has yet been performed between different biomarkers and the methodologies used to measure them, making it difficult to conduct a meta-analysis of findings from different groups. A critical evaluation and adaptation of proposed methodologies available in the literature should therefore be undertaken, to enable the investigators to choose the most suitable procedure for each chosen biomarker.

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Approaches and Methods to Measure Oxidative Stress in Clinical Samples: Research Applications in the Cancer Field

Molecular insight in the multifunctional activities of Withaferin A

Cancer, being the second leading cause of mortality, exists as a formidable health challenge. In spite of our enormous efforts, the emerging complexities in the molecular nature of disease progression limit the real success in finding an effective cancer cure. It is now conceivable that cancer is, in fact, a progressive illness, and the morbidity and mortality from cancer can be reduced by interfering with various oncogenic signaling pathways. A wide variety of structurally diverse classes of bioactive phytochemicals have been shown to exert anticancer effects in a large number of preclinical studies. Multiple lines of evidence suggest that withaferin-A can prevent the development of cancers of various histotypes. Accumulating data from different rodent models and cell culture experiments have revealed that withaferin-A suppresses experimentally induced carcinogenesis, largely by virtue of its potent anti-oxidative, anti-inflammatory, anti-proliferative and apoptosis-inducing properties. Moreover, withaferin-A sensitizes resistant cancer cells to existing chemotherapeutic agents. The purpose of this review is to highlight the mechanistic aspects underlying anticancer effects of withaferin-A.

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Withaferin-A—A Natural Anticancer Agent with Pleitropic Mechanisms of Action

Oxidative stress is considered to be involved in the pathophysiology of all cancers. In order to evaluate the total oxidant/antioxidant status in patients with thyroid cancer and to investigate the relationship between oxidative stress parameters and serum thyroid profiles among thyroid cancer patients and various controls, we determined oxidative status including total antioxidant status (TAS) and total oxidant status (TOS) and calculation of oxidative stress index (OSI) in sera in 82 thyroid cancer patients, 56 benign thyroid disease patients, and 50 healthy controls. It was found that serum TAS levels were significantly lower in patients with thyroid cancer than in controls (P<0.001), while serum TOS levels and OSI values were significantly higher (both P<0.001) in the cancer patients. No significant correlations were observed between various oxidative stress markers and thyroid profiles in either the thyroid cancer patients or the controls. Receiver operating characteristic curve analysis demonstrated that OSI was the best indicator for distinguishing cancer patients from benign thyroid diseased or healthy controls, followed by TOS and TAS. Risk estimate statistics also indicated that TOS and/or OSI were good risk factors to discriminate patients with thyroid cancer from two controls. These findings suggested that oxidants are increased and antioxidants are decreased in patients with thyroid cancer. OSI may be a more useful oxidative stress biomarker than TAS and TOS for monitoring the clinical status of thyroid cancer patients.

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Total oxidant/antioxidant status in sera of patients with thyroid cancers

INTRODUCTION Oral cancer is the fifth most frequent cancer worldwide and India has recorded the highest incidence (40-50 percent) of oral malignancy. Clerodendron inerme is used by Indian traditional practitioners for the treatment of various ailments, including cancer. Our aim was to investigate the chemopreventive potential of the aqueous leaf extract of Clerodendron inerme (CiAet) in 7,12-dimethylbenz(a) anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. METHODS We developed oral squamous cell carcinoma in the buccal pouch of male Syrian golden hamsters by painting them with 0.5% DMBA in liquid paraffin thrice a week for 14 weeks. The tumour incidence, tumour volume and tumour burden that were formed in the hamster buccal pouches were determined. RESULTS Oral administration of CiAet at a dose of 500 mg/kg body weight to DMBA-painted animals on days alternate to DMBA painting for 14 weeks significantly prevented the tumour incidence, tumour volume and tumour burden. CiAet also exerts potent antilipidperoxidative effect and improved the antioxidant defence system in DMBA-painted animals. The chemopreventive efficacy of CiAet was evident by inhibition of tumour formation (80%) in DMBA-painted animals. CONCLUSION The chemopreventive potential of CiAet is probably due to its antilipidperoxidative effect or the presence of some potent bioactive chemopreventive principles in the leaves of Clerodendron inerme.

Evaluation of anticarcinogenic effects of Clerodendron inerme on 7,12-dimethylbenz(a) anthracene-induced hamster buccal pouch carcinogenesis

The present study has investigated the chemopreventive and antilipidperoxidative effects of the ethanolic extract of Clerodendron inerme leaves (CiELet) in DMBA induced skin carcinogenesis in Swiss albino mice. The skin squamous cell carcinoma was induced in the shaved back of mice, by painting with DMBA (25 microg 0.1 mL(-1) acetone) twice weekly for 8 weeks. We have observed 100% tumor formation in the fifteenth week of experimental period. Elevated lipid peroxidation and decline in enzymatic and non-enzymatic antioxidants status was observed in tumor bearing mice. Oral administration of CiELet (300 mg kg(-1) bw) for 25 weeks significantly prevented the tumor incidence, volume and burden of the tumor. The CiELet also showed potent antilipidperoxidative effect as well as enhanced the antioxidant defense mechanisms in DMBA painted mice. The present study thus demonstrated the chemopreventive and antilipidperoxidative efficacy of CiELet in DMBA induced mouse skin carcinogenesis.

Chemopreventive and antilipidperoxidative potential of Clerodendron inerme (L) Gaertn in 7,12-dimethylbenz(a)anthracene induced skin carcinogenesis in Swiss albino mice.

The present study has investigated the antigenotoxic effect of withaferin-A, a steroidal lactone obtained from the roots and leaves of Withania somnifera, in 7,12-dimethylbenz(a)anthracene (DMBA)-induced genotoxicity. Measurement of the frequency of micronucleated polychromatic erythrocytes (MnPCEs) and chromosomal aberrations is used as cytogenetic endpoints. A single intraperitoneal injection of DMBA (30 mg/kg b.w.) to golden Syrian hamsters resulted in marked elevation in the frequency of MnPCEs and aberrations in the chromosomal structure. Hamsters pretreated with withaferin-A intraperitonealy 2 h before the injection of DMBA, significantly reduced the frequency of MnPCEs and chromosomal aberrations such as chromosomal break, gap, minute, and fragment. Our results thus demonstrated the antigenotoxic effect of withaferin-A in DMBA-induced genotoxicity in the bone marrow of golden Syrian hamsters.

Protective role of withaferin-A on 7,12-dimethylbenz(a)anthracene-induced genotoxicity in bone marrow of Syrian golden hamsters.

The levels of lipid peroxidation products (TBARS), non-enzymatic antioxidants and enzymatic antioxidants activity were investigated in plasma and erythrocytes of twenty clinically diagnosed stage II papillary thyroid cancer patients and an equal number of age and sex matched healthy subjects. An increase in the levels of lipid peroxidation products, decrease in non-enzymatic antioxidants levels and enzymatic antioxidant activities in plasma and erythrocytes were detected in papillary thyroid cancer patients as compared to healthy subjects. Impairment in antioxidant defence mechanisms are responsible for enhanced lipid peroxidation observed in plasma and erythrocytes of papillary thyroid cancer patients.

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Lipid peroxidation and antioxidants status in patients with papillary thyroid carcinoma in India.

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Chemopreventive and Antilipidperoxidative Efficacy of Piper longum (Linn.) on 7,12-dimethylbenz (a) anthracene (DMBA) Induced Hamster Buccal Pouch Carcinogenesis

Namasivayam Senthil

Papers

Evaluation of anticarcinogenic effects of Clerodendron inerme on 7,12-dimethylbenz(a) anthracene-induced hamster buccal pouch carcinogenesis

Chemopreventive and antilipidperoxidative potential of Clerodendron inerme (L) Gaertn in 7,12-dimethylbenz(a)anthracene induced skin carcinogenesis in Swiss albino mice.

Protective role of withaferin-A on 7,12-dimethylbenz(a)anthracene-induced genotoxicity in bone marrow of Syrian golden hamsters.

Lipid peroxidation and antioxidants status in patients with papillary thyroid carcinoma in India.

Chemopreventive and Antilipidperoxidative Efficacy of Piper longum (Linn.) on 7,12-dimethylbenz (a) anthracene (DMBA) Induced Hamster Buccal Pouch Carcinogenesis