Nutraceuticals in Metabolism and Xenobiotics

Recently, dietary nutraceuticals have gained increased attention in the prevention and treatment of various oxidative stress health conditions, as these natural compounds do not exhibit any significant side effects. Especially, a number of natural products are specific in eliminating harmful man-made xenobiotics and other endogenous toxic chemicals from the body by modulating the expression a multitude of xenobiotic metabolizing enzymes, drug transporters and gene regulators. Researches have shown that the nutritional deficiencies result in lowered xenobiotic metabolism. Nutraceuticals include the protecting bioactive agents in diet such as flavonoids, phenolic compounds that are non-flavonoids, essential fats/oils, bioactive peptides, probiotics, vitamins, minerals, organosulfur compounds, dietary fibers and terpenoids. This chapter mainly focusses on the influence of dietary nutrients on the diverse targets of the detoxification system involved in processing and eliminating the toxic chemicals from the body, by modulating the phase I and II metabolizing enzymes, uptake and efflux transporters of drugs, and transcriptional factors triggering the detoxification. The chapter also sheds light on the potential role of the nutraceuticals in the chemoprevention by protecting against carcinogenesis. Excessive enzymatic activity of phase I metabolism with inadequate support from phase II detoxification system results in the biotransformation of xenobiotics to carcinogenic DNA adducts leading to genotoxicity and subsequent cancer growth. Thus, the chapter also covers the potential of dietary nutrients in the inhibition of certain gene expression of detoxification system triggering the carcinogenesis or modulation of certain drug transporters in liver, kidney or intestine to enhance the bioavailability of pharmaceutical drugs.