Phytonutrients of Nutraceutical Importance: Exploring Antimicrobial, Antiproliferative, and Antioxidant Activities

Introduction

The rapidly increasing knowledge on nutrition, pharmacology and plant biotechnology has changed some concepts about food and health. Epidemiologic studies from the latest 50 years have provided evidence of an inverse association between the dietary intake of fruit and vegetables and occurrence of varied illness such as diabetes, osteoporosis, cancers, cardiovascular and infectious diseases. This protective effect obtained in food intake has been assigned to plant secondary metabolites; specifically, phytomolecules with nutritional properties, the phytonutrients. In a few words, phytonutrients can be defined as plant-derived compounds with nutritive properties that can have also curative or preventive effects over diseases (Michels et al., 2000). These phytomolecules are thought to be responsible for most of the health benefits observed in individuals that adopted long-time diets rich in fruits, vegetables, beans, cereals, and plant-based beverages such as tea and wine. The correlation between observed effects and the type or concentration of some phytomolecules has been described, such as Lycopene and Resveratrol, for instance, in cancer prevention. In plants, several phytomolecules of nutraceutical interest are part of defense mechanisms against environmental challenges such as damage due to ultraviolet light exposure and natural predators such as insects and other plagues (Hecht, 2000; Sharma et al., 2009).

The low bioavailability of phytomolecules is an important limitation on their use to prevent or treat diseases. The often low concentration found in plasma has led to some skepticism in this sense; however, in spite of their low bioavailability, varied studies in the latest years have provided evidence of their beneficial effects in humans and animals. To overcome the issue of low levels of phytonutrients in fruits and vegetables, pharmaceutical and nutritional companies have developed several pharmaceutical dosage forms of nutraceutical formulations and other dietary plant-based supplementary products. This becomes even more relevant considering that nutraceutical formulations provide adequate concentrations of phytomolecules and thus, different beneficial effects to health can be expected. Moreover, nutraceutical formulations make the use of phytonutrients feasible in a clinical perspective (McCullough et al., 2003; Key et al., 2004; Yang et al., 2010). Examples of Nutraceuticals are presented in Table 1.

ROS: Reactive oxygen species; RNS: Reactive nitrogen species.