Phytochemicals: Sources and biological functions

Abstract

Many plants are traditional sources for food and pharma products. Since the difference of a therapeutic and a toxic effect depends on the dose, there are fluent transitions between consumption, therapy and toxicity of nutraceuticals in food, medicines, or plants. The following review provides a classification of phytochemicals into categories according to their biosynthesis from carbohydrates, lipids and amino acids as well as an overview of epidemiologically important toxic phytochemicals affecting human health including examples from the terpenoids, phenolic compounds, and alkaloids families. Despite evidence indicating that phytochemicals can reduce the risk of chronic non-communicable diseases, research is still needed using new and precise methodologies to unravel the multitude of beneficial roles played by phytochemicals in human health.