Structural and antioxidant properties of newly synthesized phenol derivatives of 4,7-dihydroxycumarin

U ovoj doktorskoj disertaciji opisana je sinteza novih aminofenolnih, metoksiaminofenolnih i hidroksibenzohidrazinskih derivata 4,7-dihidroksikumarina kao i višestepeno ispitivanje antioksidativne aktivnosti bazirano na savremenim eksperimentalnim spektroskopskim i sofisticiranim računarskim (DFT) metodama. Strukture jedinjenjenja potvrđene su primenom strukturnih instrumentalnih (rendgenska strukturna i elementalna analiza, 1H NMR, 13C NMR, IR, UV-Vis) i pomenutih računarskih metoda. Veliki faktor korelacije između eksperimentalnih i simuliranih spektroskopskih podataka ukazuje na precizno definisanje struktura novosintetisanih jedinjenja. Poređenjem antioksidativnog kapaciteta određenog standardnim in vitro testovima (DPPH, ABTS, FRAP, EPR (HO•)) pokazano je da hidroksibenzohidrazinski derivati ispoljavaju najbolju aktivnost. Primena QM-ORSA metodologije, koja se bazira na teorijskoj proceni kinetičkih parametara termodinamički favorizovanih reakcionih puteva, pružila je detaljan uvid u mehanizam antiradikalskog delovanja između novosintetisanih jedinjenja i HO•. Procenjeno je da aminofenolni i metoksiaminofenolni derivati ispoljavaju antiradikalsku aktivnost preko HAT/PCET i SPLET mehanizama, dok hidroksibenzohidrazinski derivati preko SPLET i RCF mehanizama. Procenjene vrednosti ukupne konstante brzine (kukupno), koje predstavljaju merilo aktivnosti jedinjenja, pokazuju dobru korelaciju sa rezultatima EPR spektroskopije. Rezultati procene in vitro redoks statusa na ćelijskoj liniji kolorektalnog karcinoma, pokazuju da pri niskim koncentracijama, hidroksibenzohidrazinski derivati ispoljavaju antioksidativne osobine. Vrednosti farmakokinetičkih parametara, procenjenih ADMET analizom, čine hidroksibenzohidrazinske derivate kandidatima za buduća temeljna ispitivanja sa ciljem dobijanja statusa potencijalnih dijetetskih suplemenata.In this doctoral dissertation, the synthesis of new aminophenolic, methoxyaminophenolic, and hydroxybenzohydrazine derivatives of 4,7- dihydroxycoumarin is described, as well as a multi-step examination of antioxidant activity based on modern experimental spectroscopic and sophisticated computational (DFT) methods. The structures of the compounds were confirmed using structural instrumental (elemental and X-ray structural analysis, 1H NMR, 13C NMR, IR, UV-Vis) and mentioned computer methods. A high correlation factor between experimental and simulated spectroscopic data indicates a precise definition of the structures of the newly synthesized compounds. Comparing the antioxidant capacity defined by standard in vitro tests (DPPH, ABTS, FRAP, EPR (HO•)) showed that hydroxybenzohydrazine derivatives exhibit the highest activity. The application of the QM-ORSA methodology, which is based on the theoretical evaluation of kinetic parameters of thermodynamically favored reaction pathways, provided a detailed insight into the mechanism of antiradical action between newly synthesized compounds and HO•. It was estimated that aminophenolic and methoxyaminophenolic derivatives exhibit antiradical activity via HAT/PCET and SPLET mechanisms, while hydroxybenzohydrazine derivatives via SPLET and RCF mechanisms. The estimated values of the overall rate constant (koverall), which represent a measure of compound activity, show a good correlation with the results of EPR spectroscopy. The assessment results of the in vitro redox status on the colorectal cancer cell line indicate that hydroxybenzohydrazine derivatives exhibit antioxidant properties at low concentrations. The values of the pharmacokinetic parameters, estimated by the ADMET analysis, make hydroxybenzohydrazine derivatives candidates for future thorough investigations with the aim of obtaining the status of potential dietary supplements