PLANTS AND EXTRACTS, AS WELL AS SOME FRUITS AND VEGETABLES are natural sources of polyphenols (bioflavonoids) and carotenoids. Above all, the citrus extract, apple pulp, red fruits (blueberries and pomegranate), some vegetables (spinach, pumpkin and tomato), and plant extracts (thyme, rosemary and calendula) stand out. Polyphenols and carotenoids are a very broad group of substances produced naturally by plants, with a protective function against UV light and oxidation due to the formation of free radicals, against herbivorous animals (some, such as tannins, give a bitter taste) or as a lure to attract pollinating animals or dispersers of seeds and fruits (they give specific colors and aromas to attract said animals). Animals aren't capable of producing these substances, so they must obtain them from the diet by eating the plants that produce them. In animals that eat these plants, they have antioxidant action, are precursors of vitamins and have a protective effect against coronary, cerebrovascular, neurodegenerative diseases and some types of cancer.
Some of the best known bioflavonoids are quercetin, silymarin, anthocyanidins and tannins; and within the carotenoids, the -carotene, precursor of vitamin A.