Nordihydroguaiaretic acid (NDGA) is a classic lignan, a phenylpropane dimer linked by a bond between positions C8 and C8′, as opposed to a neolignan. It is a natural compound found in the creosote bush (Larrea tridentata).
The compounds of every Wikipedia article carrying a Chembox or a Drugbox, refreshed daily, with the values their infoboxes give. The pages need JavaScript; the API does not.