Page 61 - Pharmd general phytochemistry I-Final2024_LEUCTERS
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C15 ……C6-C3-C6
8 O1 2` 3` O
7 2 1` 4`
3
6 3 6` 5` OH
5 4
O O
Flavone Flavonol
(2-phenyl chromone) 3- Hydroxyflavone
O2 O
3 3
O O
Flavanone Isoflavone
(2,3-Dihydroflavone) (3-phenyl chromone)
Falvonoids constitutes the majority of the yellow- colored plant pigments.
Flavonols,Chalcones and Aurones are usually of deeper yellow color.
Flavonoidal compounds are classified into:,
1- Flavones are 2phenyl chromones (2-phenyl benzo-pyrone).
2- Flavonols are 3-hydroxyflavones.
3-Flavanones are 2,3-dihydro-derivatives of flavones (lacking the 2,3-double bond).
4- Isoflavones are 3-phenyl chromone derivatives.
5- Anthocyanidins and their glycosides (Anthocyanins)
6- Chalcones 7- Aurones
Tests for flavonoids intense yellow color
1- Flavonoids dissolve in alkalis
2- Flavonoids exhibit strong fluorescence under UV light.
Magnesium
3- Shinoda test: Flavonoids test solution pink red color
HCL
4- Flavonoids may be characterized by investigation of their U.V.
SPECTRA that usually show two main bands:
Band at higher wavelength (band I) which is attributed to
the cinnamoyl fraction of the flavonoidal structure, and
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