The stilbenoids are naturally occurring stilbene derivatives. Examples include resveratrol and its cousin, pterostilbene. The stilbestrols, which are structurally but not synthetically related to (E)-stilbene, exhibit estrogenic activity. Members of this group include diethylstilbestrol, fosfestrol, and dienestrol. Some such derivative are produced by condensation of coenzyme A derivatives of cinnamic acid or 4-hydroxycinnamic acid and the malonic acid.