Ø In the organic chemistry the class
which contains a hydroxyl group that is directly bound to an aromatic hydrocarbon
Ø Phenolic compound is a substance
which contain benzoic
molecules with one or many hydroxyl
Ø Polyphenols contain one or many hydroxyl group
Ø In plants they are produce as
secondary natural metabolites as biogenetically phenylpropanoids that’s way in
plants physiological role fulfill by them.
Plant phenolic compounds
Ø In plants phenolic compounds are
Ø In oaks and mangroves they are particularly present abundantly.
Ø Thousands of phenolic compounds are known
Ø 40% is the total of organic carbon
present in the biosphere.
Ø In vascular plants they are present
in cell wall plant defense and flower colour etc.
Ø Phenolic compounds are widely present
as secondary metabolites.
Ø In vascular plants
Ø In bryophytes
Ø In fungi bacteria and algae
Ø Nuts fish oil and vegetables contain
vitamin –E which is a fat soluble vitamin.
Ø They have not a single molecule but a
family if a molecule has four called as tocopherols and rest of these four is
Ø Vitamin-c molecule consists of one
lactone ring with two hydroxyl group on it and have two chiral carbon.
Ø Due to presence of several hydroxyl
group present in the exteracellular areas of the body so it is called water
Ø Due to its polar nature and water
solubility it can be converted from the body more readily .to neutralize the
aqueous free radical and reactive oxygen so it reacts with them.
Ø Tannin word is drived from the French
its meaning is tanning substance using for range of natural polyphenols.
Ø In 1962 swain and bate-smith
formulated the acceptable definition for vegetable tannins.
Ø Phenolic compounds have unique group
(plant tannin) of high molecular weight they have a power to complex strongly with carbohydrates and
Antioxidant properties of phenolic compound
Ø Phenolic compounds have antioxidant
action it is due to their high tendency to chelate metal with heavy metals like
copper and iron.
Ø Free radicals are main components in
plant system as well as in human body it can be easily damage cell due to
presence of free electrons.
Ø Cell damage cause by free radicals
can be repair by compounds which are released by proteins and green vegetables.
Ø For stimulants to spore germination
flavonoid compound play role as signal molecule phytoalexins detoxifying agent.
Ø Flavonoid may also play protecting
role depends on the role of microorganism in plant.
Ø anthocyanin’s are pigments which
related to the color of leaves fruits and flowers.
Ø It is used for flavoring as chemical .the flavor may be act as
repellent to pest and pollinators.
Phenolic compounds in plants defense
Ø Natural animal toxicants
Ø E.g. simple phenolic, complex
tannins and resins in the plant surface
and deter bird.
Plant whispers (communication)
A best example is the lima bean .when
caterpillar feeds on the leaf surface many things happen. A cloud of fragrances
is released due to physical damage. Chemicals are produced by all leaves for
defense because fragrance warned whole plant of the impending danger. The
fragrance mixture acts as express highway of information. Message is understand
by neighbouring plants and they also start defensive measures.