Flavonoid
Flavonoids are secondary plant substances that occur universally in plants. Meanwhile, about 8000 different flavonoids have been discovered! They fulfil a variety of functions in the plants themselves. They form the most important group of flower pigments and serve to attract insects for pollination. They are also responsible for the colours of many fruits and vegetables. They also provide frass protection from herbivorous animals. Some act as protection against UV radiation, which is especially important for plants in extreme locations, such as alpine regions. Flavonoids are thought to have particularly antioxidant properties, but they also have direct antibacterial, antiviral and antifungal (against fungal attack) effects. Various flavonoid-containing plants are therefore used medicinally. Studies have shown a lower risk of various diseases with higher flavonoid intake through a plant-based diet. Flavonoids are mainly found in the marginal layers of the plants, as well as in the outer leaves, which explains why one should not peel apples or pears, for example, or skin tomatoes