2.1. Podophyllotoxin biosynthesis
The first step in the production of PPT is the deamination of
phenylalanine by phenylalanine ammonia-lyase to cinnamic acid, which is
converted into feruloyl-CoA by caffeoyl-CoA O-methyl transferase.
Feruloyl-CoA further undergoes a series of formation of intermediates
such as coniferyl alcohol to produce pinoresinol and lariciresinol.
These compounds lead to the production of secoisolariciresinol in the
presence of pinoresinol-lariciresinol reductase leading to the synthesis
of matairesinol, which eventually yields PPT (Fig. 2 )
(Bahabadi et al., 2012;
Javadian et al., 2017).