Covering: 2000 to 2004 Lignans are a class of secondary plant metabolites produced by oxidative dimerization of two phenylpropanoid units. Although their molecular backbone consists only of two phenylpropane (C₆–C₃) units, lignans show an enormous structural diversity. There is a growing interest in lignans and their synthetic derivatives due to applications in cancer chemotherapy and various other pharmacological effects. This review deals with lignans possessing anticancer, antioxidant, antimicrobial, anti-inflammatory and immunosuppressive activities, and comprises the data reported in more than 100 peer-reviewed articles, so as to highlight the recently reported bioactive lignans that could be a first step towards the development of potential new therapeutic agents.

To search for secondary metabolites of Alnus hirsuta (Betulaceae), various chromatographic separations of the ethyl acetate soluble fraction of the stem bark of A. hirsuta led to the isolation of a new diarylheptanoid glycoside, (3R)-1,7-bis-(4-dihydroxyphenyl)-3-heptanol 3-O-β-D-glucopyranosyl(1→3)-β-D-xylopyranoside (13) and twelve diarylheptanoid derivatives, namely, oregonin (1), rubranoside A (2), hirsutanonol 5-O-β-D-glucopyranoside (3), rubranoside B (4), rubranoside C (5), hirsutanonol (6), hirsutenone (7), (5S)-O-methylhirsutanonol (8), platyphylloside (9), platyphyllonol 5-O-β-D-xylopyranoside (10), aceroside VII (11) and platyphyllenone (12). Isolates were assessed for their hepatoprotective effects against tert-butylhydroperoxide (t-BHP)-induced toxicity in HepG2 cells. Of these isolates, compounds 1—8 showed significant hepatoprotective effects on t-BHP-induced damage to HepG2 cells, with 8 exhibiting the greatest protective effect (50.7±3.7% at a concentration of 10 μM).