oxidants and antioxidants in biology - Oxygen Club of California

Synergisms in antioxidant function of different classes of
natural products
JENS MILDE, JOHANNA GRASSMANN AND ERICH F. ELSTNER
Technische Universität München - Wissenschaftszentrum Weihenstephan.
Lehrstuhl für Phytopathologie, Labor für Angewandte Biochemie,
85350 Freising-Weihenstephan, Germany
Plants have to cope with a wealth of abiotic and biotic impacts
since some 2-3 billion years. Land plants have to sustain both extreme
temperatures or dryness and high light intensities accompanied
by oxygen saturation without a chance to escape. In addition
to these abiotic impacts infections by virus, bacteria, fungi and
wounding by animals, especially insects, may have dramatic effects.
Plants thus developed a strategy for defence combining several
operative avoidance reactions with a sophisticated set of
chemicals, present either constitutively or synthesized „just in
time“. Coevolution of animals took advantage of the synthesizing
capacity of plants sparing the synthesis of certain „expensive“
groups of chemicals such as aromats (phenolics).
In our days the knowledge about these interrelationships and
connections of protective systems is exponentially increasing
leading to novel insights mainly concerning medical - pharmacological
and nutritive aspects on the following basis: One main
common problem during most diseases, both of plants and animals,
is „oxidative stress“. The biochemistry of oxygen - activation and –
detoxification analyzed in the past has led to the identification of
many similar or more or less identical features in plants and animals.
Biochemical model reactions simulating these common
situations allow to predict possible functions of plant´s defence
molecules and/or systems, to find new fields of application and to
exploit up to date unknown resources. In this report potential cooperatively
- protecting properties for both animals and plants of certain
flavonoids, carotenoids and monoterpenes („essential oils“),
based on their biochemical activities in corresponding model reactions,
both „in vitro“ and „ex vivo“, are reported. We show that in
lipid protection certain substances are only active in the presence of
corresponding cooperating partners.
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