IUBio

flavonoids

Dr. Peter Gegenheimer PGegen at UKans.nospam.edu
Sat May 16 09:42:51 EST 1998


Gee, all the pigments of the maize kernel are flavonoids. All the classical
pigmentation mutants studied by McClintock, Peterson, and others, are defects
in enzymes of the flavonoid biosynthetic pathway. All plants synthesize a
variety of flavonoids; indeed, the types of flavonoid present in different
species has been used for  phylogenetic analysis. Flavonoids are typically
stored in the vacuole (if memory serves me). The colors of petals and fruit
skins are either carotenoids (orange, red, yellow) or flavonoids, specifically
anthocyanins (red, orange, yellow, and all the blues and purples). The red of
apples and strawberries, for example, is an anthocyanin.

Most of the biochemistry of the biosynthetic pathways was worked out in
parsley, with the genetics coming from maize. More recent work with
transgenics, etc., has been done with other plants, including
horticulturally-important species.

The pathway starts with the condensation of coumaryl-CoA and malonyl-CoA,
catalyzed by chalcone synthase, to form naringenin chalcone. The pathways then
typically branch into the flavones and the flavonols (3-hydroxy-flavone).
Anthocyanidins branch from the flavonols. These pathways then proceed more or
less in parallel. The compounds become colored when they are glycosylated, and
for the anthocyanins (glycosylated anthocyanidins), when they bind divalent
cations.

As for health effects, this idea has been around for a while, but who knows?
It's certainly true that the isoflavonoids (derived from flavonoids) are among
the major anti-bacterial compounds synthesized by plants in response to
bacterial or fungal infection.

Hope this gives some help. A good plant biochem text will be your best
reference.

Peter G.
_____________________________________________
On Tue, 5 May 1998 20:12:33, "Frank Kutka" <fkutka at sage.nrri.umn.edu> wrote:

> I recently heard that "flavonoids" found in grape juice provide some
> beneficial effect in the human body.  Does anyone know if these
> compounds are found in the seeds of maize? Is their presence related
> to particular colors of seeds if they are present at all?
>
> Peace,
>
> Frank J. Kutka
> Assistant Scientist
> Natural Resources Research Institute
> 5013 Miller Trunk Hwy
> Duluth MN 55811

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