What are secondary metabolites in plants?

Secondary metabolites produced by plants are chemicals that have no defined role in the plant's metabolism, including growth, photosynthesis, reproduction and other primary functions. Many secondary metabolites produced by plants play key roles in human lives.

One type of secondary metabolite produced by plants, flavonoids, are touted as having antioxidant properties and are consumed by humans for these benefits, as well as anti-inflammatory properties. Flavonoids may also be known as Vitamin P or citrin. Phytoestrogens, a secondary metabolite found in nuts, seed and other foods, are chemicals that mimic the hormone estrogen. They are thought to protect bone and heart health.