Synthesis and Antioxidant Activity of Dihydroquinopimaric Alcohol Acylates

Objective: The aim of this study was to synthesize a new group of acyl derivatives based on methyl esters of 1β-hydroxy- and 1β,4α-dihydroxy-2,3-dihydroquinopimaric acid and evaluate their antioxidant potential. Methods: Acylation of methyl esters of 1β-hydroxy- and 1β,4α-dihydroxy-2,3-dihydroquinopimaric acid with acyl chlorides was carried out by boiling in absolute pyridine for 8 h in the presence of 4-dimethylaminopyridine (DMAP) catalyst. The structure of the synthesized acylates was confirmed by NMR spectroscopy and mass spectrometry data. The antioxidant activity of the synthesized compounds was assessed using two in vitro models: Ferric Reducing Antioxidant Power (FRAP) and the ABTS cation-radical reduction. Results and Discussion: Methyl ester of 1β,4α-dihydroxy-2,3-dihydroquinopimaric acid exhibits versatile antioxidant activity, effectively acting in both the FRAP and ABTS models. Furthermore, four of the synthesized acylates exhibit significantly higher reducing potential than the parent compounds, highlighting the potential for further optimization of these derivatives to create effective antioxidant agents. Conclusions: The identified activity characteristics highlight the potential for further structural optimization of the studied compounds to create effective antioxidant agents with a defined action profile. Expanding the range of models, in-depth study of the mechanisms of antioxidant and prooxidant action, and research into metabolic stability, bioavailability, and interactions with cellular targets will enable the creation of effective and safe antioxidant drugs with a specified action profile.