Polyphenols are a large group of chemical compounds found in plants. Although more than 8000 different polyphenols have been reported, there are four main classes of polyphenols, each with their own subgroups1:
- Flavonoids: The most studied group of polyphenols. They can be divided into six subclasses: flavonols, flavones, flavanones, flavanols, anthocyanins, and isoflavones.
- Phenolic acids: These polyphenols are abundantly found in food and can be separated into two subclasses: derivatives of benzoic acid and cinnamic acid, such as the more common hydroxycinnamates.
- Stilbenes: The occurrence of stilbenes in our diet is quite low, but one of the most studied stilbenes is resveratrol, which is found primarily in grapes and grape-related products such as red wine.
- Lignans: Unlike the first three groups, this group of polyphenols are primarily found in grains and seeds.