scholarly journals 3′,8″-Dimerization Enhances the Antioxidant Capacity of Flavonoids: Evidence from Acacetin and Isoginkgetin

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2039 ◽  
Author(s):  
Xican Li ◽  
Xiaojian Ouyang ◽  
Rongxin Cai ◽  
Dongfeng Chen
Keyword(s):  
Sulfonic Acid ◽  
Mass Spectra ◽  
Relevant Literature ◽  
Radical Scavenging ◽  
Ultra Performance Liquid Chromatography ◽  
Tandem Mass ◽  
Comparison Standard ◽  
Ic50 Values ◽  
Transfer Potential ◽  
Tof Ms

To probe the effect of 3′,8″-dimerization on antioxidant flavonoids, acacetin and its 3′,8″-dimer isoginkgetin were comparatively analyzed using three antioxidant assays, namely, the ·O2− scavenging assay, the Cu2+ reducing assay, and the 2,2′-azino bis(3-ethylbenzothiazolin-6-sulfonic acid) radical scavenging assay. In these assays, acacetin had consistently higher IC50 values than isoginkgetin. Subsequently, the acacetin was incubated with 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxy radicals (4-methoxy-TEMPO) and then analyzed by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC−ESI−Q−TOF−MS) technology. The results of the UHPLC−ESI−Q−TOF−MS analysis suggested the presence of a dimer with m/z 565, 550, 413, 389, 374, 345, 330, and 283 peaks. By comparison, standard isoginkgetin yielded peaks at m/z 565, 533, 518, 489, 401, 389, 374, and 151 in the mass spectra. Based on these experimental data, MS interpretation, and the relevant literature, we concluded that isoginkgetin had higher electron transfer potential than its monomer because of the 3′,8″-dimerization. Additionally, acacetin can produce a dimer during its antioxidant process; however, the dimer is not isoginkgetin.

scholarly journals A Null B-Ring Improves the Antioxidant Levels of Flavonol: A Comparative Study between Galangin and 3,5,7-Trihydroxychromone

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3083 ◽  
Author(s):  
Xiaojian Ouyang ◽  
Xican Li ◽  
Wenbiao Lu ◽  
Xiaojun Zhao ◽  
Dongfeng Chen
Keyword(s):  
Comparative Study ◽  
Radical Scavenging ◽  
Ultra Performance Liquid Chromatography ◽  
Reaction Products ◽  
Radical Adduct ◽  
Ic50 Values ◽  
Reducing Activity ◽  
Dpph Scavenging ◽  
Tof Ms

To clarify the role of the B-ring in antioxidant flavonols, we performed a comparative study between galangin with a null B-ring and 3,5,7-trihydroxychromone without a B-ring using five spectrophotometric assays, namely, •O2−-scavenging, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical-scavenging, 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) radical-scavenging, and Fe3+-reducing activity. The DPPH•-scavenging reaction products of these assays were further analyzed by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) technology. In the five spectrophotometric assays, galangin and 3,5,7-trihydroxychromone dose-dependently increased their radical-scavenging (or Fe3+-reducing) percentages. However, galangin always gave lower IC50 values than those of 3,5,7-trihydroxychromone. In the UPLC-ESI-Q-TOF-MS/MS analysis, galangin yielded galangin-DPPH adduct MS peaks (m/z 662, 434, 301, 227,196, and 151) and galangin-galangin dimer MS peaks (m/z 538, 385, 268, 239, 211, 195, and 151). 3,5,7-Trihydroxychromone, however, only generated m/z 3,5,7-trihydroxychromone-DPPH adduct MS peaks (m/z 586, 539, 227, 196, and 136). In conclusion, both galangin and 3,5,7-trihydroxychromone could similarly undergo multiple antioxidant pathways, including redox-dependent pathways (such as electron transfer (ET) and ET plus proton transfer (PT)) and a non-redox-dependent radical adduct formation (RAF) pathway; thus, the null B-ring could hardly change their antioxidant pathways. However, it did improve their antioxidant levels in these pathways. Such improvement of the B-ring toward an antioxidant flavonol is associated with its π-π conjugation, which can provide more resonance forms and bonding sites.

scholarly journals Rapid Analysis of the Main Components of the Total Glycosides of Ranunculus japonicus by UPLC/Q-TOF-MS

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500
Author(s):  
Wen Rui ◽  
Hongyuan Chen ◽  
Yuzhi Tan ◽  
Yanmei Zhong ◽  
Yifan Feng
Keyword(s):  
Relevant Literature ◽  
Ultra Performance Liquid Chromatography ◽  
Flavonoid Glycosides ◽  
Complex Samples ◽  
Flavonoid Aglycones ◽  
Flight Mass Spectrometry ◽  
Fragment Ions ◽  
Main Components ◽  
Acquity Uplc ◽  
Tof Ms

A rapid method for the analysis of the main components of the total glycosides of Ranunculus japonicus (TGOR) was developed using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS). The separation analysis was performed on a Waters Acquity UPLC system and the accurate mass of molecules and their fragment ions were determined by Q-TOF MS. Twenty compounds, including lactone glycosides, flavonoid glycosides and flavonoid aglycones, were identified and tentatively deduced on the basis of their elemental compositions, MS/MS data and relevant literature. The results demonstrated that lactone glycosides and flavonoids were the main constituents of TGOR. Furthermore, an effective and rapid pattern was established allowing for the comprehensive and systematic characterization of the complex samples.

scholarly journals Simultaneous Study of Anti-Ferroptosis and Antioxidant Mechanisms of Butein and (S)-Butin

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 674 ◽  
Author(s):  
Liu ◽  
Li ◽  
Cai ◽  
Ren ◽  
Zhang ◽  
...  
Keyword(s):  
Ultra Performance Liquid Chromatography ◽  
Hydrogen Atom Transfer ◽  
Tandem Mass ◽  
Reaction Products ◽  
Antioxidant Power ◽  
Flow Cytometric ◽  
Simultaneous Study ◽  
Linoleic Acid Emulsion ◽  
Antioxidant Mechanisms ◽  
Tof Ms

To elucidate the mechanism of anti-ferroptosis and examine structural optimization in natural phenolics, cellular and chemical assays were performed with 2′-hydroxy chalcone butein and dihydroflavone (S)-butin. C11-BODIPY staining and flow cytometric assays suggest that butein more effectively inhibits ferroptosis in erastin-treated bone marrow-derived mesenchymal stem cells than (S)-butin. Butein also exhibited higher antioxidant percentages than (S)-butin in five antioxidant assays: linoleic acid emulsion assay, Fe3+-reducing antioxidant power assay, Cu2+-reducing antioxidant power assay, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-trapping assay, and α,α-diphenyl-β-picrylhydrazyl radical (DPPH•)-trapping assay. Their reaction products with DPPH• were further analyzed using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS). Butein and (S)-butin produced a butein 5,5-dimer (m/z 542, 271, 253, 225, 135, and 91) and a (S)-butin 5′,5′-dimer (m/z 542, 389, 269, 253, and 151), respectively. Interestingly, butein forms a cross dimer with (S)-butin (m/z 542, 523, 433, 419, 415, 406, and 375). Therefore, we conclude that butein and (S)-butin exert anti-ferroptotic action via an antioxidant pathway (especially the hydrogen atom transfer pathway). Following this pathway, butein and (S)-butin yield both self-dimers and cross dimers. Butein displays superior antioxidant or anti-ferroptosis action to (S)-butin. This can be attributed the decrease in π-π conjugation in butein due to saturation of its α,β-double bond and loss of its 2′-hydroxy group upon biocatalytical isomerization.

scholarly journals Dual Effect of Glucuronidation of a Pyrogallol-type Phytophenol Antioxidant: A Comparison between Scutellarein and Scutellarin

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3225 ◽  
Author(s):  
Qianru Liu ◽  
Xican Li ◽  
Xiaojian Ouyang ◽  
Dongfeng Chen
Keyword(s):  
Ultra Performance Liquid Chromatography ◽  
Spectrophotometric Analysis ◽  
Dual Effect ◽  
Spectra Analysis ◽  
Ms Analysis ◽  
Radical Adduct ◽  
Ic50 Value ◽  
Ic50 Values ◽  
The One ◽  
Tof Ms

To explore whether and how glucuronidation affects pyrogallol-type phytophenols, scutellarein and scutellarin (scutellarein-7-O-glucuronide) were comparatively investigated using a set of antioxidant analyses, including spectrophotometric analysis, UV-vis spectra analysis, and ultra-performance liquid chromatography coupled with electrospray ionization-quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) analysis. In spectrophotometric analyses of the scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•), and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radicals (PTIO•) and the reduction of Cu2+ ions, scutellarein showed lower IC50 values than scutellarin. However, in •O2−-scavenging spectrophotometric analysis, scutellarein showed higher IC50 value than scutellarin. The analysis of UV-Vis spectra obtained after the Fe2+-chelating reaction of scutellarin showed a typical UV-Vis peak (λmax = 611 nm), while scutellarein showed no typical peak. In UPLC-ESI-Q-TOF-MS/MS analysis, mixing of scutellarein with DPPH• yielded MS peaks (m/z 678, 632, 615, 450, 420, 381, 329, 300, 288, 227, 196, 182, 161, and 117) corresponding to the scutellarein-DPPH adduct and an MS peak (m/z 570) corresponding to the scutellarein-scutellarein dimer. Scutellarin, however, generated no MS peak. On the basis of these findings, it can be concluded that glucuronidation of pyrogallol-type phytophenol antioxidants has a dual effect. On the one hand, glucuronidation can decrease the antioxidant potentials (except for •O2− scavenging) and further lower the possibility of radical adduct formation (RAF), while on the other hand, it can enhance the •O2−-scavenging and Fe2+-chelating potentials.

scholarly journals Inhibitory Effect and Mechanism of Action of Quercetin and Quercetin Diels-Alder anti-Dimer on Erastin-Induced Ferroptosis in Bone Marrow-Derived Mesenchymal Stem Cells

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 205 ◽  
Author(s):  
Xican Li ◽  
Jingyuan Zeng ◽  
Yangping Liu ◽  
Minshi Liang ◽  
Qianru Liu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Radical Scavenging ◽  
Ultra Performance Liquid Chromatography ◽  
Inhibitory Effect ◽  
Diels Alder ◽  
Cell Counting ◽  
Flow Cytometric ◽  
Ic50 Values ◽  
Dpph Scavenging ◽  
Antioxidant Effects

In this study, the anti-ferroptosis effects of catecholic flavonol quercetin and its metabolite quercetin Diels-Alder anti-dimer (QDAD) were studied using an erastin-treated bone marrow-derived mesenchymal stem cell (bmMSCs) model. Quercetin exhibited higher anti-ferroptosis levels than QDAD, as indicated by 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid (C11-BODIPY), 2′,7′-dichlorodihydrofluoroscein diacetate (H2DCFDA), lactate dehydrogenase (LDH) release, cell counting kit-8 (CCK-8), and flow cytometric assays. To understand the possible pathways involved, the reaction product of quercetin with the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH●) was measured using ultra-performance liquid-chromatography coupled with electrospray-ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-Q-TOF-MS). Quercetin was found to produce the same clusters of molecular ion peaks and fragments as standard QDAD. Furthermore, the antioxidant effects of quercetin and QDAD were compared by determining their 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical-scavenging, Cu2+-reducing, Fe3+-reducing, lipid peroxidation-scavenging, and DPPH●-scavenging activities. Quercetin consistently showed lower IC50 values than QDAD. These findings indicate that quercetin and QDAD can protect bmMSCs from erastin-induced ferroptosis, possibly through the antioxidant pathway. The antioxidant pathway can convert quercetin into QDAD—an inferior ferroptosis-inhibitor and antioxidant. The weakening has highlighted a rule for predicting the relative anti-ferroptosis and antioxidant effects of catecholic flavonols and their Diels-Alder dimer metabolites.

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