Flavanoid Pengetahuan Bahan Agroindustri
Flavonoids Polyphenolic compounds with 15 C atoms, 2 benzene rings on linear 3 C chain Over 4,000 flavonoids Easily recognized as flower pigments in most angiosperm plants but are not always flower pigments In plants they repair damage and shield from environmental toxins
The Most Important Classes of Flavonoids and their Biological Significance
class
number of known members
biological significance (so far as known)
anthocyanin(s)
250
red and blue pigments
chalcons
60
yellow pigments
aurones
20
yellow pigments
flavones
350
cream-coloured pigments of flowers feeding repellents (?) in leaves
flavonols
350
dihydrochalcons
10
some taste bitter
proanthocyanidins
50
astringent substances
catechins
40
some have properties like those of tannins
isoflavonoids
15
oestrogen effect, toxic for fungi
• Istilah flavonoid berasal dari kata flavon yang merupakan salah satu jenis flavonoid yang terbanyak dan lazim ditemukan (selain flavonol, antosianidin). • Flavon mempunyai kerangka 2-fenilkroman. • Berdasarkan tingkat oksidasinya, flavan adalah yang terendah dan digunakan sebagai induk tatanama flavon. 1 C
O
B
O A
O 2
OH
3 4
2-fenilkroman
flavan
katecin (flavan-3-ol)
O OH OH
leukoantosianidin (flavan-3,4-diol)
O
dihidrocalkon
O
calkon
1
NOMENCLATURE The term “flavonoid” is generally used to describe a broad collection of natural products that include a C6-C3-C6 carbon framework, or more specifically a phenylbenzopyran functionality.
B O
A
C
O
NOMENCLATURE Depending on the position of the linkage of the aromatic ring to the benzopyrano (chromano) moiety, this group of natural products may be divided into three classes: the flavonoids (2-phenylbenzopyrans) 1, isoflavonoids (3-benzopyrans) 2, the neoflavonoids (4-benzopyrans) 3. These groups usually share a common chalcone precursor, and therefore are biogenetically and structurally related.
NOMENCLATURE 5' 6'
O 4'
B 8
O
7
A
C
5
4
2'
3
6
3 3'
2
1 the flavonoids (2-phenylbenzopyrans)
2 the isoflavonoids (3-benzopyrans)
O
4
3 the neoflavonoids (4-benzopyrans)
2
2-Phenylbenzopyrans (C6-C3-C6 Backbone) Based on the degree of oxidation and saturation present in the heterocyclic C-ring, the flavonoids may be divided into the following groups: O
O
O
O
O
flavone
flavanone
flavan
O
O
O
OH
OH
OH
O
O
flavan-3-ol
dihydroflavonol
flavonol
Isoflavonoids (3-benzopyrans) Isoflavonoids possess a 3-phenylchroman skeleton that is biogenetically derived by 1,2-aryl migration in a 2-phenylchroman precursor. 8
O
O
O
2 2'
6 4 O
O
isoflavone
isoflavan
isoflavanone
O
O
OH
isoflavanol
isoflav-3-ene
Neoflavonoids (4-benzopyrans) The neoflavonoids are structurally and biogenetically closely related to the flavonoids and the isoflavonoids.
O
4-arylcoumarin
O
O
O
3,4-dihydro-4-arylcoumarin
O
neoflavene
3
Ciri struktur flavonoid • Gugus hidroksil hampir selalu ditemukan pada posisi 5 dan & 7 dari cincin A.
HO
OH
OH
OH
OH HO
HO
O
O OH
OH
O
OH
OH
OH
+ O
HO
O
O
kaemferol
apigenin
floretin
HO
OH
O
HO
O
OH
C H
OH
OH OH
sulfuretin
pelargonidin
epikatecin
OH OH
O
OH
Ciri struktur flavonoid • Cincin B flavonoid seringkali mempunyai gugus gugus hidroksil atau alkoksil pada posisi 4’, atau 3’ & 4’. • Adanya tiga gugus hidroksil atau alkoksil, atau tidak teroksigenasi sama sekali, atau teroksigenasi pada posisi 2’, sangat jarang ditemukan. • Hal tersebut disebabkan biogenesis dari flavonoid. • Glikosida senyawa flavonoid berikatan dengan gula pada gugus hidroksil yang ada.
O
O
O
O
OH
OH
O
O
flavanon
O
+ O
O
flavon
flavanonol
+ O
flavonol
O C H OH O
garam flavilium
antosianidin
auron
4
• Isoflavonoid dan neoflavonoid hanya ditemukan dalam beberapa jenis tumbuhan. • Ragam isoflavonoid: pterokarpan
isoflavon HO
MeO
O
R
O
O
O
OH
O
R=H daidzein R = OH genistein
pterokarpin
rotenoid kumestan R
R2
O
O
O
O
O
R3 R1
R
O
O
OMe
OH OMe
R1=R3=H R2=OH kumestrol R1=R3=OH R2=OMe medelolakton
R=H rotenon R = OH amorfigenin
Reaksi flavon dan flavonol • Flavon dan flavonol dengan asam mineral menghasilkan garam flavilium yang berwarna. Garam tersebut dengan basa menghasilkan kembali flavonoid semula. • Gugus fungsi oksigen pada posisi 5, 7, 4’ dapat meningkatkan stabilitas ion flavilium. 5' 6'
O
OH
OH 4'
1
8 7
2
+ O
3'
HCl
Cl:
2' 4
6
NaOH
3 R
5
R
OH
O R= H flavon R=OH flavonol
Anthocyanins Basically anthocyanins are 3,5,7-thihydroxy flacylium salts and are classified based on the substitution pattern in the B ring of the molecule. Generally 3-hydroxy and 5-hydroxy positions are glycosylated. R4
R4
R4
R5
O
R3
R5
R5 R3
+ O
R3
O R6
R6 R1
R1 R2
Cl-
Anthocyanidin R1=R2=R3=R4=R5=R6 =H,OH or OMe or glycoside/ Anthocyanin
R2
O
Derivatives of flavones including glycosides R1=R2=R3=R4=R5=R6 =H,OH or OMe or Alkylor glycoside/ glycoside
R6 R2 R1
O R9
R7 R8
Derivatives of isoflavones including glycosides R1=R2=R3=R4=R5=R6=R7=R8=R9 =H,OH or OMe or Alkylor glycoside/ glycoside
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• The anthocyanodins constitute a large family of differently coloured compounds and occur in countless mixtures in practically all parts of most higher plants. They are of great economic importance as fruit pigments and thus are used to colour fruit juices, wine and some beverages. • The anthocyanidins in Hydrangea, colours it RED in acid soil and BLUE in alkali soil.
Sumber Flavanoid
1.1 occurrence Flavonoids are widely distributed in nature and are especially common in higher plants belonging families Leguminoseae, Rutacee, Primulaceae, Polygonaceae, Salicaceaem Pinaceae, Rosaceae, Asteraceae, Lamiaceae, Bignoniaceae, Moraceae, Betulaceae, Rubiaceae, and Mytaceae.
Flavonoids are found to occur in different parts of the plants ( roots, bark, heartwood, leaves, flowers, fruits and seeds).
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biological activities Green Tea • potent antioxidant compounds that have demonstrated greater antioxidant protection than vitamins C and E, • increase the activity of antioxidant enzymes, • inhibit cancer by blocking the formation of cancercausing compounds and suppressing the activation of carcinogens. The major polyphenols in green tea are flavonoids (catechin, epicatechin and so on).
Flavonoids
Act like antioxidants. How effective they are depends on their molecular structural characteristics Some flavonoids in hops and beer have been found to have better antioxidant effects than tea or red wine; most flavonoids are found in fruits, vegetables, teas, and other drinks. Flavonoids have been known to have antiviral, antiallergic, antiplatelet, anti-inflammatory, antitumor and antioxidant activities
SELAMAT UJIAN
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