Slide bài giảng Tìm hiểu về glycosides

Glycosides • Definition: Organic natural compounds present in a lot of plants and some animals, these compounds upon hydrolysis give one or more sugars (glycone) β_form and non sugar (aglycone) or called genin. • Solubility: glycosides are water soluble compounds and insoluble in the organic solvents. Glycone part: water soluble, insoluble in the organic solvents. Aglycone part: water insoluble, soluble in the organic solvents. Some glycosides soluble in alcohol. Separation between glycosides parts: Glycosides glycone +aglycone +HCL G + A +salt+H2O (H2O+G)+A (H2O+G)+(chloroform+A) We can separate them by using separatory funnel The best solvent to extract aglycone is Ethyl acetate because: A- immiscible in water. B- always presents in the upper layer. Neutralization by Using alkaline Filtration chloroform Hydrolysis +HCLdil Note: Alcohol and acetone are water miscible compounds,so we can't use them as organic solvents for aglycone separation. physico-chemical properties of glycosides(general) • Colorless, solid, amorphous, nonvolatile (flavonoid- yellow, anthraquinone-red or orange. • Give positive reaction with Molisch's and Fehling's solution test (after hydrolysis). • They are water soluble compounds, insoluble in organic solvents • Most of them have bitter taste (except: populin, glycyrrhizin, stevioside). Cont • Odorless except saponin (glycyrrhizin). • when a glycosides has a lot of sugars its solubility in water decrease. • Glycosides hydrolyzed by using mineral acids and temperature or by using enzymes such as: a- Emolsin Bitter almond seeds. b- Myrosin or Myrosinase black mustard seeds. c- Rhamnase glycosides containing rhamnose as sugar part. Biosynthesis of glycosides (O-glycosides) • UTP(Uridine Triphoshate) +sugar-1-phoshate UDP-sugar + ppi(Pyrophosphate inorganic). • UDP-sugar +acceptor (aglycone) Acceptor-sugar +UDP Uridylyl transferase Enzyme Glycosyl transferase Enzyme Glycosyl transferase Enzyme The function or the role of glycosides in the plant organism • Converting toxic materials to non or less toxic. • Transfer water insoluble substances by using monosaccharide. • Source of energy (sugar reservoir). • Storing harmful products such as phenol. • Regulation for certain functions(growth). • Some have beautiful colours(pollenation process). Cont… • Some glycosides have antibacterial activity, so they protect the plants from bacteria and diseases. Bitter almond Amygdalin bacteria HCN hydrolysis kill Eomlsin enzyme Classification of glycosides [...]... carboxyl group • S -glycosides : in these glycosides the sugar attached to a Sulfur atom of aglycone such as in sinigrin • N -glycosides : in these glycosides the sugar linked with Nitrogen atom of (-NH2,-NH-)amino group of aglycone like in nucleosides DNA,RNA • C -glycosides : in these glycosides the sugar linked (condensed) directly to Carbon atom of aglycone like in aloin N.B C -glycosides are not... of glycosides according to glycone part • Glucose _ glucoside group like in Sennoside • Rhamnose _ Rhamnoside like in frangullin • Digitoxose _ Digitoxoside like in digoxin • Glucose and Rhammnose _ Glucorhamnoside _ glucofrangulin • Rhamnose and glucose _ Rhamnoglucoside _ Rutin Classification of glycosides on the basis of the linkage between glycone and aglycone part • O -glycosides : in these glycosides. .. of glycosides according to their therapeutic effects • CHF and cardiac muscles stimulators such as: a-Digitalis glycosides: digoxin, digitoxin, gitoxin (Fox glove leaves) b- Ouabain: Strophanthus gratus seeds c- K-strophanthin -Strophanthus kombe seeds d- Scillaren A,B which isolated from red and white Squill bulbs e- Convolloside:Convallaria majalis – Lily of the Valley …Cont • Laxative group of glycosides: ... lead acetate to precipitate them Classification of glycosides according to a glycone part 1- phenolic group of glycosides: Such as arbutin which isolated from bearberry leaves Uses: UTI as antiseptic and antibacterial & mild diuretic Drugs : -Esoterica :cream :age spots -hydroquinone solution : wet hands 2- saponin group of glycoside a Important group of glycosides which widely distributed specially in... activity Classification of Flavonoids according to the main nucleus Flavonoids M ain nucleus flavonoids glycosides Flavonol unsaturated yellow quercetin Quercitrin Rhamnoglucoside Flavone (unsat) Yellow Diosmetin Vitexin Flavanone (satur) colorless H esperitin Naringin C.G (Cardiac glycosides) : group of glycosides which has powerful action on ) cardiac muscles (cardiac muscle stimulant C.G glycone part... sulfur glycoside or thio glycoside ) 1 Group of glycosides which contains sulfur (S-glycoside) 2 Present in many cruciferous plants, on hydrolysis 3 They produce isothiocynate (SCN) aglycone Such as : 1.sinigrin which founded in Black Mustard seeds 2.sinalbin which founded Brassica These plants contain also enzyme myrosin (myrosinase) which hydrolyze these glycosides Properties of M ustard oil : 1.Irritant... 1.Anti-bacterial 2.Anti-hyperlipidemic activity HDL 3.anti-histaminic 4.anti-coagulant 5.Immune system stimulant ** Coated tablet and capsules stomach acid inactivates alliinase enzyme Cyanogenic glycosides Group glycosides which widely distributed between the members of Rosaceae family They gave with hydrolysis HCN (Hydrocyanic acid) They derived from nitrile of mandelic acid Cyanosides like : 1 Amygdalin... Prunase hydro.Prunasin Flavonoids Large group of glycosides which widely distributed in the plants kingdom and in all plants parts (leaves, roots, rhizomes, fruits peels) Various colors in flowers( yellow, orange, red, purple.) They are benzo-gama-pyrone derivatives Their chemical structure based on (C 6 C 3 C 6 ) The general uses of Flavonoids and Flavonoid glycosides 1 Increase elasticity of blood vessels... enzymes mainly Classification of glycosides according to a glycone part : 1- if a glycone part alcohol -this group called alcoholic group like Salicin 2- if a glycone part aldehyde- this group called aldehydic gr like glucovanillin 3- if phenol called phenolic group like arbutin 4-if cyanone called cyanogenic or cyanophoric or cyanoside like amygdalin 5-if thio called glycosides or isothiocyanate glycoside... ( panaxoside) Triterpenoid + steroidal nucleus Ginseng root uses : 1- stimulant 4-adaptogenic agent Drugs : 1- geriatric pharmaton 2- gerimax 3- polyvit 2- Tonic 3- anti-stress Anthraquinone group of glycosides 1 They are anthracene derivatives (anthracene = is the main nucleus for anthraquinone compounds 2 In the plant they biosynthesized from acetyl-CoA and malonyl-CoA 3 They have cathartic property . isolated for example: 1-salicin –salix- 2-cascaroside _cascara 3-aloin- Aloe vera 4- sennoside – senna- 5-frangulin – frangula 6- glycyrrhizin – glycyrrhiza And others. Always glycosides founded. group. • S -glycosides : in these glycosides the sugar attached to a Sulfur atom of aglycone such as in sinigrin. • N -glycosides : in these glycosides the sugar linked with Nitrogen atom of (-NH2,-NH-)amino. seeds. b- Myrosin or Myrosinase black mustard seeds. c- Rhamnase glycosides containing rhamnose as sugar part. Biosynthesis of glycosides (O -glycosides) • UTP(Uridine Triphoshate) +sugar-1-phoshate