Radical Scavenging and antimicrobial activity of extracts of three cultivar of Castanea Sativa Mill. have been examined. Leaf and catkins have been extracted under the same conditions by 50% ethanol as extragens, afterwards dry extracts of examined samples have been gained. Total phenolic content was determined by HPLC, subsequent to preliminary acid hydrolysis of samples. For determination of extract infl uence to creating and transformation of hydroxide (OH) radicals and (DPPH) radicals, extracts have been dissolved in distillated water and added to Fenton’s model system
in concentration of 0.2 mg/ml. High value antioxidant activity (AA) in relation to hydroxyl radicals has turned out catkins from Lovran chestnut (59.09%). The greatest antiradical activity in relation to DPPH radicals occurred with extracts of catkins from domestic sweet chestnut (37.50). The antimicrobial tests have showed that ethanol extracts of leaf and catkins inhibited growth of Gram positive bacteria.Ispitivano je uklanjanje radikala i antimikrobna aktivnost ekstrakata, tri kultivara Castanea Sativa Mill. Lišće i rese su ekstrahirane pod istim uvjetima 50%-tnim etanolom kao ekstragensom, a zatim su dobiveni suhi ekstrakti ispitivanih uzoraka. Nakon izvršene kisele hidrolize uzoraka ukupne fenolne tvari su ordređene HPLC-om. Radi određivanja efekta ekstrakata na stvaranje i transformiranje hidroksil (OH) radikala i (DPPH) radikala, ekstrakti su rastvoreni
u destiliranoj vodi i dodani u Fenton-ov model sistem, do fi nalne koncentracije od 0,2 mg/ml. Visoka vrijednost antioksidativne aktivnosti (AA) u odnosu na hidroksil radikale određena je za resu Lovranskog kestena (59,09%). Najveća antiradikalna aktivnost u odnosu na DPPH radikale je utvrđena kod ekstrakta rese domaćeg pitomog kestena (37,50). Antimikrobni test je pokazao da etanolni ekstrakti rese i lista inhibiraju rast Gram pozitivnih bakterija