Phenolic compounds

1
Phenolic compounds
By Dr/ Amani S. Awaad Professor of
pharmacognosy, King Saud University
2
???????? ????????? Phenolic compounds
?????? ????? ???? ????? ????? ??? ?????. ??????
????????? ????? ?? ???????? ?? ???????
???????????? ???? ???????? ?????? ???? ??????
??????? ???? )?????? ?????? ????? sulphate ??
(acetyl
Group of secondary plant products or
compounds Composed of a hydroxyl group attached
to an aromatic ring A broad range of compounds -
found in all components of plants leaves,
flowers, fruit etc Function of most compounds is
unknown Comprised of many groups Flavonoids,
Tannins, Lignin etc. All very chemically diverse!
????? ?????????
???? ????? ???????? ????????? ????? ???? ????
??????? ?? ?????? ??????? ??? ?? ???? ???????
??????
3
????? ?????????
4
?????? ???????? ?????????
??? ??????? ?? ??? ???? ??????????(?????,?????
---???)
???? ?? ???? ????? ?????? ?????? ?????? ? ??????
?????? ?? ???????
??? ???????? ?????????
?) ????????????
?) ??????????
?) ??????? ????????? ???????
?) ???????????
?) ???????????
? ) ???????????? ???????????
?) ?????????
5
?????? ??????? ?????????

6
???????????? Flavonoids
There is growing evidence from human feeding
studies that the absorption and bioavailability
of specific flavonoids is much higher than
originally believed
???? ?? ????? ???? ???????? ?????
??????? ???????
1- ?????? ??????? 2- ???? ?????? ?? ???????.
??????? ??????
Most widely studied group of phenolics over 3000
described Water soluble pigment Seem to have
major health benefits for humans Variety of
important functions in plants
1- ????? ?? ???????? ??????? 2- ?? ??????? (???
???????) 3-?? ?????? ??????(???? ????? ??????
???????)
7
?????? ??????????? flavonoids Chemistry of

• Structure
• Aglycone (aglycone)
• Glycoside (aglyconesugar)

???? ???????? ((Pigments.

• ???? ??? ?????? ((C15 .
• ?????? ?? ??????? ??????????? ??? ?????? ???????
  (???????) ???? ??? ???? ????????? ??????????
  ???????? ????????.
• ??? ???? ?????.
• - ??? ?? ??????

Flavonoids naturally occurring low molecular wt
phenols consisting of 2 benzene rings linked via
a heterocyclic pyrone or pyran ring They are
benzo-?-pyrone derivatives so not open by alkalis.
- ??? ????? ????? ?????
Number and specific positions of OH groups /
nature of substitutions determine whether
flavonoids function as antioxidant,
anti-inflammatory, cytotoxic or antimutagenic
agents in vitro or in vivo.
8
?????? ??????????? flavonoids Chemistry of
C6 - C3 - C6
- ????? ??? - C 15 ?? ???? ???????? ????? ????
????? ?? ?????? 2, 3, ?? 4
?????? 2 ?????? ?? ??????? ????? ?????? ?????
??????
- ??? ?? ???????? ??? ???????? ??? 2 ???? 3 (
????????)
9
????? ???????????? classes of Flavoniods
1-?????????? Chalcones
2- ?????? Flavone
4- ???????? Flavanone
3- ???????? Flavonol
6- ???????????? ????? ??????
5- ?????????? Anthocyanins ?????????????
Anthocyanidin
Neoflavonoid
Isoflavonoids
10
Flavanols

• The structure of flavanols is similar to its
  counter parts except it is lacking an oxygen
  group at the 4-position of the heterocyclic
  C-ring (Hollman and Arts, 2000).

11
Some Flavanols Structure
?????? Flavone
???????? Flavonol
4- ???????? Flavanone
Isoflavonoids
12
Flavonol Fruits and Vegetables
Quercetin
Kaempferol
Myricetin
13
????? ?? ???????????? Detection and
identification of flavonoids
?)????? ??????
Blue colour with FeCl3. Yellow colour with
Alkalis. Yellow colour with AlCl3.
1) ?????? ????? (???????? ???? ????)
2) ??? ??? ((UV HCl 3) ??????? ???????( ?????????
Flavanol ??????????? Flavanone) ??? ????. 4)
??????? ??????? ?????????? (SbCl4 ).
?)????? ?????????
??????? ) (OH????? ????? ????? ?? ???
????? ??????? ???? ???????? ???? ???????? ??
????????? ?????? ??????? ?????? ?????? ?? ??????
?????????? ??? ???? ????? ????? ???? ????????????
?? ???? ??????? ?????-???? ????-???? ??????(???
????)
?)????? ??????
1- ????? ?????? . 2- ?????? ??????????
????????1HNMR ????????13CNMR 3-?????? ?????
??????? UV ??? ???? 270-460 - ????????? ??
????????? AlCl3 - - ????????? ?? ?????????
AlCl3 HCl . - ????????? ?? ????????? NaOAc
- ????????? ?? ????????? NaOAcH3BO3.
14
????? ???????????? synthesis of flavonoids
??? ?????? ????????????
-????????? (????) -TLC- PC- CC
15
???????? ?????? ???????????? Flavonoids
biosynthisis
This pathway (unique to plants) leads to the
formation of the aromatic amino acids
phenylalanine and tyrosine and to the formation
of many other phenyl-C3 compounds.
Phenylpropanoids
Phenyl-C3
Cleavage of the C3 side chain leads to many
phenyl-C1 compounds.
Phenyl-C1
16
SHIKIMIC ACID
Shikimate Pathways
CHORISMIC ACID
( acetogenin piece)
PHENYL-C3 COMPOUNDS
PREPHENIC ACID
FLAVONOIDS
17
NARINGENIN
shikimic acid
A FLAVONE
malonyl-CoA 3x

Michael addition
internal Claisen and enolizations
naringenin
18
(No Transcript)