General Introduction Lignans are a diverse group of natural polyphenolic compounds found primarily in plants. They are a subgroup of non-flavonoid polyphenols, derived from the oxidative coupling of two phenylpropanoid units (C6-C3). Lignans are biosynthesized from phenylalanine through the shikimic acid pathway. They are structurally characterized by a 2,3-dibenzylbutane skeleton, …