Chemopreventive Agents Inhibit NfkB Activation

Several agents that suppress carcinogenesis have been shown to block NF-kB activation. These include curcumin, green tea polyphenols, silymarin, and resveratrol (Fig. 1). Curcumin is a polyphenol (diferuloylmethane) derived from the roots of Curcuma longa, and it inhibits both tumor initiation induced by BP and 7,12 dimethylbenz(a)anthracene and phorbol ester-induced tumor promotion (61-63). Both B a P and phorbol esters are potent activators of NF-kB. Curcumin has also been shown to suppress...

Introduction To Free Radicals And Antioxidants

The chemical definition for free radicals (oxidants) is atoms or groups of atoms with one or more unpaired electrons.'' This property makes them very unstable and highly reactive, trying to capture the needed electron from other compounds to gain stability. When the attacked molecule loses its electron, it becomes a free radical itself, beginning a chain reaction. Some free radicals, such as the toxic oxyradical species hydroxyl radical (*OH) or the less reactive superoxide radical (O2* ),...

Cooperative Interaction Between iNos And Ho1

Nadph Heme

Biological function of HO system, the nonheme enzymes that oxidize heme to generate CO and the function of NOS system, the heme-containing enzymes that use heme to produce NO, is related to heme. HO degrades heme, but NOS needs heme. However, there are certain similarities and differences between the HO and NOS systems. As for the similarities, both the HO and NOS enzyme systems have constitutive and inducible isoforms. Expression of the inducible form of NOS (iNOS) is enhanced by some of the...

Mechanisms Of Antioxidant Defense By Flavonoids

Three different modes of action are indicated by the available evidence. 1. The mechanism which has been most extensively investigated is metal chelation preventing free radical formation and secondly, the direct scavenging of oxygen and nitrogen free radicals such as hydroxyl, superoxide, and nitric oxide radicals. Most of these studies have been made in vitro or ex vivo systems. Evidence for such activity in body tissues is generally absent or inconclusive. A pro-oxidant action of quercetin...

Conclusion

In the past decade, nutrition research has undergone an important shift in focus from epidemiology and physiology to molecular biology and genetics. This is a result of a growing realization that the effects of nutrition on health and disease cannot be understood without a profound understanding of how nutrients act at the molecular level micronutrients and macronutrients can be potent dietary signals that influence the metabolic programming of cells and have an important role in the control of...

Contributors

Amit Agarwal Natural Remedies Research Center, Bangalore, India Bharat B. Aggarwal Cytokine Research Section, Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, U.S.A. Yukihiro Akao Gifu International Institute of Biotechnology, Gifu, Japan Okezie I. Aruoma Department of Applied Science, London South Bank University, London, U.K. Debasis Bagchi Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton...

OF NFjBdriven Gene Induction By Phytoestrogens

Several nutrients and non-nutritive phytochemicals are being evaluated in intervention trials for their potential as health benefiting compounds (28,179-181). Despite significant advances in our molecular understanding of various diseases, little is known about the mechanism of action of most phytochemicals (12,29,30,64,182). The chemopreventive effects that most dietary phytochemicals exert are likely to be the sum of several distinct mechanisms. A wide array of phenolic substances,...

Oxidative Stressgenerating Systems In Hypercholesterolemia

Under normal physiological conditions, nitric oxide (NO) predominates over O2 in vascular endothelial cells. The excess NO regulates endothelial cell function, modulates CAM expression, inhibits leukocyte adhesion, and limits platelet activation (adhesion and aggregation). However, a large amount of evidence has amassed in the literature that implicates oxidative stress, a consequence of increased reactive oxygen species (ROS) generation and decreased NO bioavail-ability, in the chronic...

Neuroactive Responses In Vivo To Ginkgo Biloba Egb 761

An important limitation of the in vitro assay of gene expression analysis of herbal extracts is that it does not account for the processes that affect bioavailability and biotransformation. These biological processes of the alimentary tract and the liver will modify herb components. Therefore, an in vivo study was undertaken in normal mice to define the potential in vivo transcriptional activity of EGb 761 (3). The hypothesis was that a centrally active herbal extract should change the gene...

Antioxidant Protective Genes

An important effect of oxidative stress in the lungs is the upregulation of protective antioxidant genes. The antioxidant glutathione (GSH) is concentrated in epithelial lining fluid compared with plasma (101) and has an important protective role, together with its redox enzymes, in the airspaces and intracellularly in epithelial cells. Human studies have shown elevated levels of glutathione in epithelial lining fluid in chronic cigarette smokers compared with nonsmokers (26,101). However, this...

Phytoestrogens

Thousands of chemical structures have been identified in plant foods. Given the wide range of botanical species and plant parts from which phytochemicals are derived, they can contribute a significant variety and complexity to the human diet (27). In the past, the medicinal uses of spices and herbs were often indistinguishable from their culinary uses, and for good reason people have recognized for centuries both the inherent value, as well as the potential toxicity, of phytochemicals in...