Glycosides and Tannins

Glycosides

Compounds that yield one or more sugars upon hydrolysis

Glycosides

Any molecules in which sugar groups is bonded through glycosidic bond.

• acetals

• hydroxyl of the sugar

• hydroxyl group

• secondary hydroxyl

• oxide ring

Glycosides are chemically defined as ____ in which the _____ is condensed with a _____ of non-sugar components and the ______ is condensed within the sugar molecule itself to form an _____

• Aglycone

• Glycone

Glycosides have two types:

Aglycone

A type of Glycosides that has non-sugar component

Glycone

A type of Glycosides that have sugar component

• Crystalline or Amorphous substances

• Water and alcohol soluble

• Insoluble in organic solvents

• Hydrolyzed by the presence of water, enzymes and mineral acids

• Optically active

Characteristics of Glycosides

• a-form

• B-form

Isomeric forms of Glycosides

• Regulatory

• Protective

• Sanitary

importance of glycosides in plants:

• Basis of Glycone

• Basis of Glycosidic bond

• Basis of Aglycone

Classification of Glycosides

• C-Glycoside

• O-Glycoside

• N-Glycoside

• S-Glycoside

Types of Glycosidic Linkage:

O-Glycoside

Linkage on phenol group

N-Glycoside

Linkage on Amino group

S-Glycoside

Linkage on Thiol group

C-Glycoside

Linkage on Carbon group

• Senna

• Aloe

• Rhubarb

Examples under the class: Anthraquinone Glycosides

• Digitalis

• Thevetia

• Squill

Examples under the class: Sterol or Cardiac glycosides

• Dioscorea

• Liquorice

• Ginseng

Examples under the class: Saponin glycosides

• Bitter almond

• Wild cherry bark

Examples under the class: Cyanogenetic and Cyanophoric Glycosides

• Black mustards

Examples under the class: Thiocyante and Isothiocyanate glycosides

Gingko

Examples under the class: Flavone glycosides

Vanilla

Examples under the class: Aldehyde glycosides

• Bearberry

Examples under the class: Phenol glycosides

• Solanum

Examples under the class: Steroidal glycosides

• Gentian

• Picrrohiza

• Chirata

Examples under the class: Bitter and miscellaneous glycosides

UDP-sugar + PPi

Glycosides Biosynthesis: UTP + Sugar 1-P ⇋ ______ + ________

Acceptor-sugar + UDP

Glycosides Biosynthesis: UDP-sugar + acceptor ⇋ _______ + _______

UTP—glucose-1-phosphate uridylyltransferase

Enzyme involved in the Biosynthesis of glycosides

• Anthraquinone

• Saponin

• Cyanophore

• Isothiocyante

• Flavanol

• Alcohol

• Aldehydes

• Lactone

• Phenol

• Cardiac

Enumerate glycosides based on the chemical nature of their aglycone

bonus

bonus