22 Questions
What is the product of acid hydrolysis of Diosmin?
Diosmitin, glucose, and rhamnose
What is the chemical structure of Rutin?
5,7,3´,4´-tetrahydroxy flavonol-3-O-rutinoside
What is the pharmacological effect of Diosmin?
It is used to treat all of the above
What is the classification of Diosmin?
Flavone glycoside
What is the product of enzymatic hydrolysis of Rutin?
Quercetin, rutinose, and rhamnose
What is the biochemical property of Rutin?
All of the above
What is the source of Diosmin?
Barosma betulina leaves
What is the brand name of Diosmin-containing tablets?
Diosed ®, Dioven® and Daflon'
What is the general structure of flavonoids?
C-15 skeleton formed of two benzene rings
What is the origin of one of the benzene rings in flavonoids?
Shikemic acid pathway only
What is the effect of alkalies on flavonoids?
Flavonoids give a yellow color with alkalies
What is the therapeutic use of flavonoids containing plants as buchu?
Diuretic
What is the biochemical property of flavonoids?
Contain conjugated aromatic systems
What is the effect of conc.H2SO4 on flavones and flavonols?
They give a yellow color with conc.H2SO4
What is the classification of flavonoids based on their structure?
O-glycosides and C-glycosides
What is the pharmacological effect of isoflavone derivatives?
Estrogenic effect
What is the result of the reaction between flavonoids and Wilson's reagent?
A bright yellow colour with yellowish green fluorescence
What is the effect of aluminium chloride on flavonoids?
Formation of a yellow coloured complex
What is the purpose of Shinoda's test?
To detect the presence of flavonoids
What is the basic skeleton for all types and classes of flavonoids?
Flavon
What is the result of the isomerization of flavanones?
Formation of chalcones which give orange to lemon colour
What is the reaction between flavonoids and lead acetate?
Formation of a yellow coloured precipitate
Study Notes
Flavonoids
- Flavonoids are a large group of natural phenols derived from the parent substance flavone.
- They are amongst the dye stuffs and water-soluble pigments of plant origin, often yellow pigments.
- Flavonoids are derivatives of 1,3-diphenylpropane, with a C-15 skeleton formed of two benzene rings linked together by a pyran ring.
Structure and Classification
- The basic skeleton for all types and classes of flavonoids is flavan.
- Flavonoids are classified into different groups based on the presence or absence of OH- at C-3, ketone at C-4, and unsaturation between C-2 and C-3.
Identification and Characterization
- Flavonoids give yellow coloured precipitate with lead acetate.
- Flavonoids with free hydroxy group at C-5 react with boric acid and citric acid in anhydrous acetone to give a bright yellow colour with yellowish green fluorescence.
- Flavonoids form a yellow coloured complex with 5% alcoholic AlCl3.
- Alcoholic plant extract with Mg metal and conc. HCl gives red to violet or orange colour.
Occurrence and Uses
- Flavonoids are abundant in many plant families such as Rutaceae, Leguminosae, Umbelliferae, and Compositae.
- Flavonoids have various therapeutic uses, including as diuretics, antispasmodics, and antioxidants.
Flavone Glycosides
- Apiin is a flavonoid found in parsley, used as an antispasmodic and diuretic.
- Diosmin is a flavonoid found in Buchu leaves, used as a diuretic, urinary tract antiseptic, and in the treatment of peripheral vascular disorders.
Flavonol Glycosides
- Rutin is a flavonol glycoside found in Ruta graveolens and Eucalyptus, used to treat capillary fragility, hemorrhage, bleeding gums, hemorrhoidal disease, menorrhagia, and varicose veins.
This quiz is about the identification and characterization of flavonoids, including their reactions with lead acetate, boric acid, and other reagents.
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