Biological activity of origano ( origanum vulgare) extracts

Namen diplomskega dela je bil preučiti biološko aktivnost ekstraktov origana (Origanum vulgare). Osredotočili smo se na njegovo antiokisdativno ter protimikrobno delovanje. S pomočjo različnih ekstrakcijskih metod in topil smo pridobili ekstrakte origana za nadaljnje analize. Ekstraktom smo določili antioksidativno učinkovitost, kjer smo uporabili radikalsko metodo DPPH in tako določili stopnjo inhibicije prostih radikalov. Nato smo s pomočjo plinske kromatografije z masno spektrometrijo merili vsebnost in koncentracijo osmih najbolj zastopanih komponent v origanu. Za ugotavljanje protimikrobnega delovanja smo uporabili difuzijsko metodo z diski. Zaviralno učinkovitost origana smo tako opazovali proti gram negativni bakteriji Escherichia coli, gram pozitivni bakteriji Staphylococcus aureus in glivi Candida albicans. Rezultati so pokazali, da je najboljši izkoristek ekstrakcije dala ekstrakcija po Soxhletu, kjer smo kot topilo uporabili mešanico etanola in vode (70 : 30). Prav vsi ekstrakti so pokazali visoko antioksidativno delovanje, najvišji % inhibicije dal ekstrakt pridobljen z ultrazvočno kopeljo. Tudi pri tem ekstraktu je bilo kot topilo uporabljena mešanica etanola in vode v razmerju 70 : 30. Kromatografske analize ekstraktov so pokazale, da je v vzorcih prisotna visoka vsebnost karvakrola, sledijo mu timol, linalol in karvon. Najvišje koncentracije so bile določene v vzorcih, pridobljenih z ekstrakcijo po Soxhletu in ultrazvočno ekstrakcijo, kjer je bila kot topilo uporabljena mešanica etanola in vode. Protimikrobno delovanje smo zaznali pri glivi Candida albicans, vendar ni bilo mogoče izmeriti premera inhibicijske cone. Ekstrakti so pokazali relativno nizko protimikrobno učinkovitost napram bakterijama Escherichia coli in Staphylococcus aureus. Razlog je lahko v slabem raztapljanju ekstrakta ali pa so posamezne molekule aktivnih komponent prevelike, da bi se difundirale skozi trden medij.The objective of this diploma thesis was to study biological activity of oregano extract (Origanum vulgare). We focused on its antioxidative and antimicrobial activity. Oregano extracts for further analyses were obtained with different extraction methods and solvents. By using DPPH method we determined the antioxidative efficiency of the extracts and the level of free radicals inhibition. Furthermore, gas chromatography–mass spectrometry method was used to measure the presence and concentration of eight predominant components in oregano. Antimicrobial activity was performed by disc diffusion method. We observed the slowing down efficiency of oregano against Escherichia coli (Gram­), Staphylococcus aureus (Gram+) and fungus Candida albicans. The results showed the best extraction efficiency when using soxhlet extraction, where mixture of ethanol and water (70:30) was used as solvent. All the extracts showed high antioxidative activity. The highest percent of exhibition was obtained when using shaker water bath with the same ethanol and water solvent ratio (70:30). In addition, the chromatographyextract analyses showed the high presence of carvacrol, followed by thymol, linalool and carvone. Antimicrobial activity was detected at fungus Candida albicans, however, its inhibition zone diameter could not be measured. Extracts showed relatively low antimicrobial activity compared to Escherichia coli and Staphylococcus aureus bacteria. The reason for such result could lie in poor extract dissolving or in too big molecules of active components that cannot be percolated through a solid medium