Radical scavenger competition of alizarin and curcumin: a mechanistic DFT study on antioxidant activity

Abstract

In vivo hydroxyl, peroxyl, and superoxide free radicals caused by oxidative stress can be toxic to molecules that are essential for the human body. However, there are natural compounds that can decrease the amount of these harmful species. In this work, we are focusing on two well-known compounds, alizarin (red) and curcumin, to study their interactions with these small radicals for a comparison between a rigid and a flexible structure. We made a mechanistic study and found the major and minor degradation products of curcumin as well as the autoxidation products of it based on a wide range of literature. We found several more favored pathways than those that were previously proposed. On the contrary, for degradation/oxidation of alizarin, only a few proposed mechanisms can be found which were performed in specific conditions. Our calculations predicted some favored rearrangements for the alizarin by peroxyl and superoxide radicals. Graphical abstract

Theoretical studies on the kinetics and mechanism of hydroxyl radical reaction with quinclorac and quinmerac herbicides in aqueous media

“…Regarding the rearrangement of the less stable OH‐adduct, the most plausible pathway is the cleavage of CC bond leading to the ring opening process. The ring opening process leads to the formation of biradical type of species which eventually stabilizes after reacting with another available • OH radical and finally forming ketonic analogues similar to the degradation products observed in the • OH radical reaction with alizarin and curcumin [65].…”

“…These results were then compared with IEFPCM solvation model and can be seen in the supplementary information (Table S1). Recently, Sadatsharifi & Purgel have also performed a detail comparison between these two solvation models in the hydroxyl, peroxyl, and superoxide free radicals reaction with alizarin and curcumin [65].…”

Oxidative Stress and Cancer: Harnessing the Therapeutic Potential of Curcumin and Analogues Against Cancer

“…Both the keto-enol and phenolic group of Cur are thought to be the site responsible for radical scavenging, and other groups have suggested that hydrogen cleavage is the preferred ROS interaction mechanism of Cur. 52 In clinical trials, Cur is shown to increase total antioxidant capacity (TAC) and decrease malondialdehyde. 53 It also affects energy metabolism and increases overall ROS accumulation in SiHa cervical cancer cells resulting in increased autophagy and G2/M phase cell cycle arrest.…”

Effect of curcumin nanoparticles on proliferation and migration of mouse airway smooth muscle cells and airway inflammatory infiltration

“…Curcumin (CUR), a polyphenolic compound derived from the roots and stems of the curcuma plant (Gong et al, 2021;Jabbar et al, 2023), exhibits potent anti-inflammatory and antioxidant properties (Peng et al, 2021). Notably, CUR demonstrates robust free radical scavenging activity when compared to natural extracts like anthocyanins and β-carotene (Sadatsharifi and Purgel, 2021), suggesting its superior antioxidant efficacy over vitamins. In addition to scavenging reactive oxygen species and reactive nitrogen, CUR also elicits the upregulation of antioxidant enzymes (Guo et al, 2020).…”