Elucidation of reactive oxygen species scavenging pathways of norbergenin utilizing DFT approaches

Abstract

Bergenin is a polyphenolic compound that contains isocoumarin skeletal derived from C -glycosylated 4- O -methylgallic acid. The biological activities of this compound and its derivatives are quite diverse. Recent studies reveal neuroprotective effects in vitro and in vivo in Alzheimer's. Norbergenin is a demethylated form of bergenin, known for better antioxidant capacity and associated with neuroprotective properties through oxidative stress inhibition. This study focused on investigating the scavenging mechanism of norbergenin with the • OH, • OOH, and O 2 ∙ − as a radical model under physiological and lipid environments. The thermodynamic and kinetic parameters of the hydrogen transfer (HT), single electron transfer (SET), sequential proton lost-electron transfer (SPLET) and radical adduct formation (RAF) mechanisms were determined theoretically by the density functional theory (DFT) at M06-2X/6-311 + + G(d,p) level of theory. Based on the computational results, this compound has proved as an excellent • OOH and • OH scavenger under physiological conditions better than Trolox and vitamin C, whereas its radical demonstrated as an efficient O 2 ∙ − scavenger.

Theoretical insight of reactive oxygen species scavenging mechanism in lignin waste depolymerization products

“…The Eyringpy program was utilized to acquire the tunneling transmission coefficient ( κ ), as done by prior works. 44,68–71 For any scavenging mechanism that involved electron transfer, such as SET and SPLET, Marcus theory (eqn (6)) was performed to find their activation energy . 72,73 …”

“…From our previous research, one observed phenomenon is the predominance of the HT (hydrogen transfer) mechanism by phenolic groups in antioxidant compound. 44 Meanwhile, other fragments, such as benzyl groups, exhibit higher activation energy.…”

“…From our previous research, one observed phenomenon is the predominance of the HT (hydrogen transfer) mechanism by phenolic groups in antioxidant compound. 44 Meanwhile, other fragments, such as benzyl groups, exhibit higher activation energy. Thermodynamic and kinetic assessments are still insufficient to rationally explain the different required energy during the reaction.…”

Traditional Uses, Pharmacology and Phytochemistry of the Medicinal Plant Flueggea virosa (Roxb. ex Willd.) Royle

“…were also found, such as norbergenin, 11-O-acetyl bergenin and 11-O-caffeoylbergenin isolated from the leaves of F. virosa, together with flavonoid glycosides (e.g., kaempferol 3-O-(4-galloyl)-β-D-glucopyranoside) and phenolic derivatives [110,136,137]. Among these products, the demethoxylated form of bergenin, which is known as norbergenin (Figure 3a), is a potent inhibitor of oxidative stress, acting as an efficient scavenger for oxygen-based radicals [138] and a potent anti-inflammatory agent [139].…”

Chemical Insights into Oxidative and Nitrative Modifications of DNA

“…It reacts with most biomolecules at diffusion-controlled rates (k > 10 9 M −1 s −1 ). Due to its high reactivity, its half-life is extremely short (10 −9 s) [81].…”