Antioxidant and antimicrobial potential of polyphenols from foods

Abstract

Change in the lifestyle is causing the overproduction of reactive oxygen species (ROS), free radicals, and decreasing the physiological antioxidant capacity. ROS can also cause protein and lipid oxidation, nucleic acid mutation, and further responsible for the development of various diseases including cancer, cardiovascular diseases, cataract, ageing, etc. Antioxidants can prevent the oxidation of biomolecules. Antioxidants present in food are now being preferred by consumers instead of synthetic antioxidants due to their non-toxic and non-carcinogenic effects. Antioxidants present in leafy vegetables, fruits, herbs, spices, seeds, alcoholic, and non-alcoholic beverages have the ability to reduce the damage caused by ROS. Polyphenols have redox potential high enough to scavenge or terminate ROS and also provide the environment favourable for inhibition of bacterial growth. Polyphenols also have metal ion chelating property which causes the deficiency of essential metal ions in the growth medium and ultimately responsible for antimicrobial effect. Binding of the polyphenols to the thiol groups at the active site of various microbial enzymes makes them inactive, thus inhibiting the growth of microbes. Polyphenols particularly phenolic acids and flavonoids have great potential as food additives with pharmaceutical, nutraceutical, and food preservative properties. The aim of this chapter is to present some valuable natural sources of polyphenols, structural characteristics, main classes of polyphenolic compounds, and extraction of polyphenols and also provide information on the most recent developments in the chemical investigation of polyphenols, emphasising their antioxidant and antimicrobial potential.