Antioxidant Activity in vitro of 2-Antipyrine-, (5-Thioxo-2,5-Dihydro-1H-1,2,4-Triazol)-6-YL-, (1,3,4-Thiadiazol-2-YL)-6-Carboxamide-, 6-Thioureide-, and 6-Hydrazinothiol Derivatives of Maleopimarimide

Abstract

New derivatives of maleopimaric acid containing phenylthioureide fragments were synthesized. The antioxidant activity of 24 maleopimaric acid derivatives in the 2- and 6-positions was studied in three in vitro models, i.e., FRAP, reduction of DPPH radical, and reduction of ABTS radical. Methyl-, 2-isonicotinoyl-, and 2-(pyridin-3-ylcarbonyl)hydrazinocarbonothioyl derivatives of 2-allylmaleopimarimide showed antioxidant activity in vitro in the ABTS model comparable to the reference drug ascorbic acid and superior than that of Trolox.