For instance, berberine, which is secreted by golden thread (Coptis spp), is a secondary metabolite. Berberine is incredibly bitter, and its purpose is to prevent insects biting the plant.
例如黃蓮分泌的黃蓮素，即是二次代謝物，奇苦無比，目的在阻止小蟲啃蝕。