Polyphenols are natural compounds found in plants, primarily functioning as antioxidants and defense mechanisms against UV radiation and pathogens. They are abundant in fruits, vegetables, beverages, and cereals, with significant amounts present in red wine, tea, and coffee. Epidemiological studies suggest that long-term consumption of polyphenol-rich diets may reduce the risk of chronic diseases such as cancer, cardiovascular disease, diabetes, osteoporosis, and neurodegenerative disorders. Polyphenols are classified into several groups, including phenolic acids, flavonoids, stilbenes, and lignans, each with distinct structures and biological activities. Polyphenols are absorbed in the gastrointestinal tract, often in conjugated forms, and undergo extensive metabolism in the liver, leading to various metabolites that may have different biological activities. Bioavailability varies among polyphenols, and their absorption is influenced by factors such as food matrix, processing, and storage. Polyphenols can cross the blood-brain barrier, contributing to their neuroprotective effects. Polyphenols exhibit antioxidant, anti-inflammatory, and anti-carcinogenic properties, protecting against oxidative stress and cellular damage. Resveratrol, found in red wine, has cardioprotective effects by inhibiting platelet aggregation and reducing LDL oxidation. Quercetin, found in onions, has anti-diabetic and anti-aging properties. Flavonoids, such as those in tea and berries, have been shown to improve endothelial function and reduce the risk of cardiovascular diseases. Polyphenols also play a role in preventing neurodegenerative diseases like Alzheimer's and Parkinson's by reducing oxidative stress and inflammation. They may help in treating asthma by reducing airway inflammation and improving lung function. Additionally, polyphenols have antiviral properties, such as inhibiting HIV-1 and SARS-CoV-2. Despite their potential health benefits, the mechanisms of action of some polyphenols are not fully understood. Further research is needed to elucidate their bioavailability, metabolism, and mechanisms of action to optimize their use in disease prevention and treatment. Overall, polyphenols are promising candidates for the prevention and management of chronic diseases due to their diverse biological activities and potential therapeutic applications.Polyphenols are natural compounds found in plants, primarily functioning as antioxidants and defense mechanisms against UV radiation and pathogens. They are abundant in fruits, vegetables, beverages, and cereals, with significant amounts present in red wine, tea, and coffee. Epidemiological studies suggest that long-term consumption of polyphenol-rich diets may reduce the risk of chronic diseases such as cancer, cardiovascular disease, diabetes, osteoporosis, and neurodegenerative disorders. Polyphenols are classified into several groups, including phenolic acids, flavonoids, stilbenes, and lignans, each with distinct structures and biological activities. Polyphenols are absorbed in the gastrointestinal tract, often in conjugated forms, and undergo extensive metabolism in the liver, leading to various metabolites that may have different biological activities. Bioavailability varies among polyphenols, and their absorption is influenced by factors such as food matrix, processing, and storage. Polyphenols can cross the blood-brain barrier, contributing to their neuroprotective effects. Polyphenols exhibit antioxidant, anti-inflammatory, and anti-carcinogenic properties, protecting against oxidative stress and cellular damage. Resveratrol, found in red wine, has cardioprotective effects by inhibiting platelet aggregation and reducing LDL oxidation. Quercetin, found in onions, has anti-diabetic and anti-aging properties. Flavonoids, such as those in tea and berries, have been shown to improve endothelial function and reduce the risk of cardiovascular diseases. Polyphenols also play a role in preventing neurodegenerative diseases like Alzheimer's and Parkinson's by reducing oxidative stress and inflammation. They may help in treating asthma by reducing airway inflammation and improving lung function. Additionally, polyphenols have antiviral properties, such as inhibiting HIV-1 and SARS-CoV-2. Despite their potential health benefits, the mechanisms of action of some polyphenols are not fully understood. Further research is needed to elucidate their bioavailability, metabolism, and mechanisms of action to optimize their use in disease prevention and treatment. Overall, polyphenols are promising candidates for the prevention and management of chronic diseases due to their diverse biological activities and potential therapeutic applications.