Radical scavenging activity of some natural tropolones by density functional theory

The structural and electronic properties of alkannin and its derivatives and their radicals were investigated at density functional level. It turned out that the presence of the dihydroxy functionality increases the radical stability through hydrogen bond formation. The hydrogen atom transfer for alkannin derivatives is difficult to occur compared with zero compound phenol. However, alkannin derivatives appear to be good candidates for the one-electron-transfer, particularly for alkannin derivatives with –OCOCH=CH(CH3)2 and –OCOCH2CH(CH3)2 groups. It suggests that 1–7 are expected to be the promising candidates for radical scavenging activity compounds because The ionization potential (IP) values of 1–7 are lower than that of the zero compound phenol.

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COMBINED EXPERIMENTAL AND COMPUTATIONAL STUDY OF THE RADICAL SCAVENGING ACTIVITY OF LUTEOLIN

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633613500211 ◽

2013 ◽

Vol 12 (05) ◽

pp. 1350021 ◽

Cited By ~ 3

Author(s):

ABDULLAH G. AL-SEHEMI ◽

AHMAD IRFAN ◽

SALHA MANA ALJUBIRI ◽

KAMEL HUSSEIN SHAKER

Keyword(s):

Density Functional Theory ◽

Absorption Spectra ◽

Density Functional ◽

Computational Study ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

2D Nmr ◽

Hydrogen Atom Transfer ◽

Functional Theory ◽

Polarized Continuum Model

The luteolin has been extracted from Euphorbia schimperiana then 1H NMR, 13C NMR and 2D NMR spectra were measured. The ground-state geometries have been computed by using density functional theory (DFT) at B3LYP/6-31G* and M06/6-31++G** level of theories. The time dependent density functional theory (TD-DFT) has been applied to compute the absorption spectra with and without solvent. The absorption spectra have been computed in methanol to check the effect of solvent using the polarized continuum model (PCM). On the basis of bond dissociation enthalpy (BDE) and the adiabatic ionization potential (IP), we have explained the antioxidant activity of luteolin and its rotamer/positional isomer. Two mechanisms have been explained for the radical scavenging processes, i.e. hydrogen atom transfer and one-electron transfer.

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Predicting Notable Radical Scavenging Sites of Gnetin C Using Density Functional Theory

Materials Science Forum ◽

10.4028/www.scientific.net/msf.966.229 ◽

2019 ◽

Vol 966 ◽

pp. 229-233

Author(s):

Vera Khoirunisa ◽

Lusia Silfia Pulo Boli ◽

Rizka Nur Fadilla ◽

Adhitya Gandaryus Saputro ◽

Heni Rachmawati ◽

...

Keyword(s):

Density Functional ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Heterocyclic Ring ◽

Polarizable Continuum Model ◽

Hydroxyl Groups ◽

Scavenging Activity ◽

Functional Theory ◽

Water Solvent ◽

Polarizable Continuum

We have been investigating the scavenging activity of gnetin C theoretically in the molecular level. In this work, we perform density functional based calculations to predict the possible site of gnetin C for free radical scavenging activity. The water solvent effect is considered as polarizable continuum model. All possible scavenging sites have been evaluated by obtaining the bond dissociation enthalpy (BDE) for one hydrogen atom abstraction. The results demonstrate that O-H bonds generally have lower BDE relative to C-H bonds of gnetin C. We also find that C-H bonds in 5-membered heterocyclic ring have exceptionally lower BDE. This could be additional possible sites for gnetin C to scavenge more free radicals in addition to hydroxyl groups.

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Sorbicillasins A–B and Scirpyrone K from a Deep-Sea-Derived Fungus, Phialocephala sp. FL30r

Marine Drugs ◽

10.3390/md16070245 ◽

2018 ◽

Vol 16 (7) ◽

pp. 245 ◽

Cited By ~ 6

Author(s):

Zhenzhen Zhang ◽

Xueqian He ◽

Qian Che ◽

Guojian Zhang ◽

Tianjiao Zhu ◽

...

Keyword(s):

Deep Sea ◽

Density Functional ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Time Dependent ◽

Scavenging Activity ◽

Functional Theory ◽

Ic50 Value ◽

Td Dft ◽

Dependent Density

Two new nitrogen-containing sorbicillinoids named sorbicillasins A and B (1 and 2) and a new 3,4,6-trisubstituted α-pyrone derivative, scirpyrone K (3), together with two known biosynthetically related polyketides (4–5), were isolated from the deep-sea-derived fungus Phialocephala sp. FL30r by using the OSMAC (one strain-many compounds) method. The structures of 1–3, including absolute configurations, were deduced based on MS, NMR, and time-dependent density functional theory (TD-DFT) calculations of specific ECD (electronic circular dichroism) spectra. Compounds 1 and 2 possessed a novel hexahydropyrimido[2,1-a] isoindole moiety, and compound 3 exhibited weak radical scavenging activity against DPPH (2,2-diphenyl-1-picrylhydrazyl) with an IC50 value of 27.9 μM.

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Radical-Scavenging and UV-Radiation Absorption Activities of Aaptamine Derivatives: DFT and TD-DFT Studies

10.26434/chemrxiv.14493846.v1 ◽

2021 ◽

Author(s):

Thi Hoai Nam Doan ◽

Thi Le Anh Nguyen ◽

Nguyen Thi Ai Nhung ◽

Duong Tuan Quang ◽

Duy Quang Dao

Keyword(s):

Density Functional ◽

Antioxidant Activities ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Hydrogen Atom Transfer ◽

Radiation Absorption ◽

Functional Theory ◽

Radical Adduct ◽

Td Dft ◽

Potential Applications

Antioxidant and UV absorption activities of three aaptamine derivatives including piperidine[3,2-b]demethyl(oxy)aaptamine (C1), 9-amino-2-ethoxy-8-methoxy-3H-benzo[de][1,6]naphthyridine-3-one (C2), and 2-(sec-butyl)-7,8-dimethoxybenzo[de]imidazo[4,5,1-ij][1,6]-naphthyridin-10(9H)-one (C3) were theoretically studied by density functional theory (DFT). Optimized geometries of C1C3 and theirs intrinsic thermochemical properties such as bond dissociation energy, proton affinity, and ionization potential were calculated at DFT/M05-2X/6-311++G(d,p) level of theory in vacuo and in water. The results show that C1C3 exhibited similar potent antioxidant activities, which are comparable to well-known antioxidants such as Trolox or cembrene. The radical scavenging activity of the antioxidants were then investigated by evaluation the Gibbs free energy (ΔrG0) of the reaction between C1C3 and the HOO●/HO● radicals via four mechanisms, including: hydrogen atom transfer (HAT), single electron transfer (SET), proton loss (PL) and radical adduct formation (RAF). Kinetic calculation reveals that HOO● scavenging in water is occurred via HAT mechanism with C1@C19 while RAF is more dominant with C2 and C3. Antioxidant activity of aaptamine derivatives can be classified as C1 > C3 > C2. In addition, all compounds are active in UV-Vis absorption; the excitations of which are determined as π-π* transition. Overall, the results suggest the potential applications of the aaptamines in pharmaceutics and cosmetics, i.e. as sunscreen and antioxidant ingredient<br>

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