Biological effects of phenolic acids from selected Lamiaceae species

U okviru ovog doktorskog rada po prvi put je provedeno opsežno usporedno istraživanje bioloških učinaka 14 prirodnih fenolnih kiselina, prevalidacija metode određivanja ukupnih hidroksicimetnih derivata u biljnim drogama, fitokemijska karakterizacija fenolnih kiselina i flavonoida te biološki učinci odabranih vrsta roda Micromeria Bentham (Lamiaceae). Antioksidacijski učinak fenolnih kiselina ispitan je primjenom četiri različite spektrofotometrijske metode. Hidroksicimetne kiseline su pokazale bolja antioksidacijska svojstva u odnosu na većinu hidroksibenzojevih kiselina, a iznimno dobar antioksidacijski učinak utvrđen je za ružmarinsku, kavenu i galnu kiselinu. Citotoksični učinak fenolnih kiselina ispitan je na HepG2 i THP 1 staničnim kulturama primjenom MTS testa, pri čemu većina testiranih kiselina nije pokazala značajnije smanjenje vijabilnosti stanica. Istraživanje protuupalnog djelovanja fenolnih kiselina istaknulo je galnu, ružmarinsku, klorogensku, kavenu i sinapinsku kiselinu kao dobre inhibitore interleukina-6. Komet testom na uzorku humane krvi nakon tretiranja bovericinom, dokazan je dobar antigenotoksični učinak svih ispitanih fenolnih kiselina.Fitokemijska analiza fenolnih kiselina i flavonoida u biljnim vrstama porodice Lamiaceae provedena je primjenom kromatografskih (HPTLC, RP-HPLC-DAD, LC-ESIMS/ MS) i spektrofotometrijskih metoda. U etanolnim ekstraktima vrsta M. croatica, M. juliana i M. thymifolia identificirano je jedanaest fenolnih kiselina i petnaest flavonoida. Kriptoklorogenska, neoklorogenska, 3-p- i 4-pkumaroilkina, 3-(3,4- dihidroksifenil)mliječna, salvianolna kiselina B i J te dimer i trimer ružmarinske kiseline po prvi put su identificirane u navedenim vrstama. Izuzev luteolinskih i akacetinskih derivata u vrstama M. juliana i M. thymifolia, ostali su flavonoidi također prvi put identificirani u ispitivanim vrstama roda Micromeria. Ustanovljena su dobra antioksidacijska, protuupalna i antigenotoksična svojstva odabranih biljnih vrsta, pri čemu se istaknula endemična vrsta M. croatica. Dobiveni rezultati ukazali su na veliki biomedicinski potencijal ispitanih fenolnih kiselina i vrsta roda Micromeria.A comprehensive comparative study of the biological effects of 14 natural phenolic acids, prevalidation of total hydroxycinnamic assays, identification of phenolic acids and flavonoids as well as biological activities of selected Micromeria species were conducted for the first time in this doctoral thesis. Antioxidant activity of phenolic acids was tested using four different spectrophotometric methods. Hydroxycinnamic acids had better antioxidant properties than most hydroxybenzoic acids. Evaluation of antioxidant activity highlighted rosmarinic, caffeic and gallic acids as the best ones. Cytotoxic effect of phenolic acids was studied on HepG2 and THP-1 cell cultures using MTS test, and phenolic acids did not show significant reduction of cell viability. Investigation of phenolic acids' anti-inflammatory activity revealed gallic, rosmarinic, chlorogenic, caffeic and sinapinic acids as good inhibitors of interleukin-6 production. Comet assay on human blood cells treated with beauvericin proved good antigenotoxic effects of all tested phenolic acids. Phytochemical analysis of polyphenols was carried out using various chromatographic (HPTLC, RP-HPLC-DAD, LCESI- MS/MS) and spectrophotometric methods. Eleven phenolic acids and fifteen flavonoids were identified in the ethanolic extracts of M. croatica, M. juliana and M. thymifolia. Chriptochlorogenic, neochlorogenic, 3-p- and 4-pcoumaroylquinic, 3-(3,4- dihydroxyphenil)lactic, salvianolic acid B and J as well as dimer and trimer of rosmarinic acid were identified in these species for the first time. With exception of luteolin and acacetin derivatives in M. juliana and M. thymifolia, flavonoids were identified for the first time in the tested species. Good antioxidant, antiinflammatory and antigenotoxic properties were established for investigated Micromeria species with special emphasis on endemic M. croatica. Obtained results revealed the great biomedical potential of tested phenolic acids and Micromeria species