Phytochemical characterization and radical scavenger activity of flavonoids from Helichrysum italicum G. Don (Compositae).
The glycosidic fraction of the flavonoids extracted from the flowering tops of the Helichrysum italicum G. Don was isolated, purified and characterized. This fraction was constituted by three compounds, which were assigned the structure of 4,2',4',6'-tetrahydroxychalcone-2'-glucoside, kaempferol-3-glucoside and naringenin-glycoside. Radical scavenger properties of the single glycosyl-flavonoids and of the in toto glycosidic fraction were tested with in vitro systems where different reactive oxygen species are generated (superoxide ions, hydroxyl radicals) and on lipid peroxidation induced by ADP/Fe2+ and NADPH or CCl4 in rat liver microsomes. The formation of reactive oxygen species was detected by cytochrome c reduction, salicylic acid hydroxylation and hyaluronic acid depolymerization. The action of the glycosidic fraction on the release of TXB2 and 12-HETE in human platelets, after collagen stimulation, was also evaluated. The glycosidic fraction inhibited in a dose dependent fashion lipid peroxidation in rat liver microsomes treated with ADP/Fe2+ or CCl4. This effect is due to the ability of flavonoids to scavenge free radicals at different stages of the process (superoxide ions, hydroxyl and lipid peroxide radicals). The single glycosyl-flavonoids exhibited a different scavenger activity, depending on the oxygen species and the chemical structure of the compounds. No effect of the fraction was observed on TXB2 and 12-HETE formation at 100 microns concentration.
Facino
R M
RM
Chemical Pharmaceutical Toxicological Institute, Faculty of Pharmacy, University of Milan, Italy.
Carini
M
M
Franzoi
L
L
Pirola
O
O
Bosisio
E
E
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D002855:Chromatography, Thin Layer; D005260:Female; D005419:Flavonoids / Q000032:analysis / Q000494:pharmacology*; D016166:Free Radical Scavengers; D005609:Free Radicals; D006027:Glycosides / Q000032:analysis; D006801:Humans; D006820:Hyaluronic Acid / Q000032:analysis; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D066298:In Vitro Techniques; D008054:Lipid Peroxides / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000378:metabolism; D010936:Plant Extracts / Q000032:analysis / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012997:Solvents; D013929:Thromboxane B2 / Q000378:metabolism
D005419:Flavonoids; D016166:Free Radical Scavengers; D005609:Free Radicals; D006027:Glycosides; D006893:Hydroxyeicosatetraenoic Acids; D008054:Lipid Peroxides; D010936:Plant Extracts; D012997:Solvents; D013929:Thromboxane B2; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D006820:Hyaluronic Acid; D009245:NADH Dehydrogenase