Aucubin

[4] Aucubin was found to protect against liver damage induced by carbon tetrachloride or alpha-amanitin in mice and rats when 80 mg/kg was dosed intraperitoneally.

The stereochemical configurations at C5 and C9 lead to cis fused rings, which are common to all iridoids containing carbocyclic- or seco-skeleton in non-rearranged form.

[8] The initial steps of the pathway involve the fusion of three molecules of acetyl-CoA to produce the C6 compound 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA).

[8] IPP is the basic C5 building block that is added to prenyl phosphate cosubstrates to form longer chains.

biosynthesis studies suggest that the most probable synthetic sequence from 10-hydroxygerinol to 8-epi-iriotrial is the following: dephosphorylation of GPP, leads to a geranyl cation that is then hydroxylated to form 10-hydroxygeraniol; 10-hydroxylgeraniol is isomerized to 10-hydroxynerol; 10-hydroxynerol is oxidized using NAD to form a trialdehyde; finally the trialdehyde undergoes a double Michael addition to yield 8-epi-iridotrial.

[6] The cyclization reaction to form the iridoid pyran ring may result from one of two routes: Based on deuterium tracking studies, the biosynthetic pathway for aubucin from the cyclized lactone intermediate is organism specific.