Exploring the DPPH Radical Scavenging Potential in 5-Arylidene-N,N-diethylthiobarbiturates

Objective: To screen the synthesized analogues for their in vitro DPPH free radical scavenging activity. Due to their high efficacy and inexpensiveness compared to natural antioxidants, synthetic antioxidants are frequently used. The current work is primarily concerned with investigating the free radical scavenging activity of derivatives of thiobarbituric acid, based on the findings of the literature review. Methods: A series of N,N-diethylthiobarbiturates (I–XVII) were synthesized, and screened for their DPPH radical scavenging activity. Results and discussion: Limited structure-activity relationship has been established on the basis of different substituents and their varying positions. These synthetic compounds showed varying degree of inhibition in the range of IC₅₀ values 20.28 ± 0.15 to 286.19 ± 0.16 μM. Limited structure-activity relationship was revealed that hydroxyl containing compounds (V) (IC₅₀ = 20.28 ± 0.15 μM), (IV) (IC₅₀ = 22.89 ± 0.19 μM), and (I) (IC₅₀ = 26.34 ± 0.03 μM) showed comparable free radical scavenging activities with standard quercetin (IC₅₀ = 16.96 ± 0.14 μM). Conclusions: The study indicates that N,N-diethylthiobarbiturate derivatives have the potential to be synthetic antioxidants since they have strong DPPH radical scavenging action. Additionally, molecules with hydroxyl substituting demonstrate efficacy that is comparable to that of the natural antioxidant quercetin.