Antioxidant Mechanisms of Echinatin and Licochalcone A
Echinatin and its 1,1-dimethyl-2-propenyl derivative licochalcone A are two chalcones found in the Chinese herbal medicine <i>Gancao</i>. First, their antioxidant mechanisms were investigated using four sets of colorimetric measurements in this study. Three sets were performed in aqueous...
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| Format: | Article |
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MDPI AG
2018-12-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/24/1/3 |
| _version_ | 1811266625084588032 |
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| author | Minshi Liang Xican Li Xiaojian Ouyang Hong Xie Dongfeng Chen |
| author_facet | Minshi Liang Xican Li Xiaojian Ouyang Hong Xie Dongfeng Chen |
| author_sort | Minshi Liang |
| collection | DOAJ |
| description | Echinatin and its 1,1-dimethyl-2-propenyl derivative licochalcone A are two chalcones found in the Chinese herbal medicine <i>Gancao</i>. First, their antioxidant mechanisms were investigated using four sets of colorimetric measurements in this study. Three sets were performed in aqueous solution, namely Cu<sup>2+</sup>-reduction, Fe<sup>3+</sup>-reduction, and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-scavenging measurements, while 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging colorimetric measurements were conducted in methanol solution. The four sets of measurements showed that the radical-scavenging (or metal-reduction) percentages for both echinatin and licochalcone A increased dose-dependently. However, echinatin always gave higher IC<sub>50</sub> values than licochalcone A. Further, each product of the reactions of the chalcones with DPPH• was determined using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS). The UPLC-ESI-Q-TOF-MS/MS determination for echinatin yielded several echinatin⁻DPPH adduct peaks (<i>m</i>/<i>z</i> 662, 226, and 196) and dimeric echinatin peaks (<i>m</i>/<i>z</i> 538, 417, and 297). Similarly, that for licochalcone A yielded licochalcone A-DPPH adduct peaks (<i>m</i>/<i>z</i> 730, 226, and 196) and dimeric licochalcone A peaks (<i>m</i>/<i>z</i> 674 and 553). Finally, the above experimental data were analyzed using mass spectrometry data analysis techniques, resonance theory, and ionization constant calculations. It was concluded that, (i) in aqueous solution, both echinatin and licochalcone A may undergo an electron transfer (ET) and a proton transfer (PT) to cause the antioxidant action. In addition, (ii) in alcoholic solution, hydrogen atom transfer (HAT) antioxidant mechanisms may also occur for both. HAT may preferably occur at the 4-OH, rather than the 4′-OH. Accordingly, the oxygen at the 4-position participates in radical adduct formation (RAF). Lastly, (iii) the 1,1-dimethyl-2-propenyl substituent improves the antioxidant action in both aqueous and alcoholic solutions. |
| first_indexed | 2024-04-12T20:46:39Z |
| format | Article |
| id | doaj.art-0eadd71901ed4e41a747a177f48258e5 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-04-12T20:46:39Z |
| publishDate | 2018-12-01 |
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| spelling | doaj.art-0eadd71901ed4e41a747a177f48258e52022-12-22T03:17:14ZengMDPI AGMolecules1420-30492018-12-01241310.3390/molecules24010003molecules24010003Antioxidant Mechanisms of Echinatin and Licochalcone AMinshi Liang0Xican Li1Xiaojian Ouyang2Hong Xie3Dongfeng Chen4School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, ChinaSchool of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, ChinaSchool of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, ChinaSchool of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, ChinaSchool of Basic Medical Science, Guangzhou University of Chinese Medicine, Guangzhou 510006, ChinaEchinatin and its 1,1-dimethyl-2-propenyl derivative licochalcone A are two chalcones found in the Chinese herbal medicine <i>Gancao</i>. First, their antioxidant mechanisms were investigated using four sets of colorimetric measurements in this study. Three sets were performed in aqueous solution, namely Cu<sup>2+</sup>-reduction, Fe<sup>3+</sup>-reduction, and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-scavenging measurements, while 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging colorimetric measurements were conducted in methanol solution. The four sets of measurements showed that the radical-scavenging (or metal-reduction) percentages for both echinatin and licochalcone A increased dose-dependently. However, echinatin always gave higher IC<sub>50</sub> values than licochalcone A. Further, each product of the reactions of the chalcones with DPPH• was determined using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS). The UPLC-ESI-Q-TOF-MS/MS determination for echinatin yielded several echinatin⁻DPPH adduct peaks (<i>m</i>/<i>z</i> 662, 226, and 196) and dimeric echinatin peaks (<i>m</i>/<i>z</i> 538, 417, and 297). Similarly, that for licochalcone A yielded licochalcone A-DPPH adduct peaks (<i>m</i>/<i>z</i> 730, 226, and 196) and dimeric licochalcone A peaks (<i>m</i>/<i>z</i> 674 and 553). Finally, the above experimental data were analyzed using mass spectrometry data analysis techniques, resonance theory, and ionization constant calculations. It was concluded that, (i) in aqueous solution, both echinatin and licochalcone A may undergo an electron transfer (ET) and a proton transfer (PT) to cause the antioxidant action. In addition, (ii) in alcoholic solution, hydrogen atom transfer (HAT) antioxidant mechanisms may also occur for both. HAT may preferably occur at the 4-OH, rather than the 4′-OH. Accordingly, the oxygen at the 4-position participates in radical adduct formation (RAF). Lastly, (iii) the 1,1-dimethyl-2-propenyl substituent improves the antioxidant action in both aqueous and alcoholic solutions.https://www.mdpi.com/1420-3049/24/1/3antioxidantechinatinlicochalcone A1,1-dimethyl-2-propenylα,α-dimethyl-β-propenylradical adduct formationdimer |
| spellingShingle | Minshi Liang Xican Li Xiaojian Ouyang Hong Xie Dongfeng Chen Antioxidant Mechanisms of Echinatin and Licochalcone A Molecules antioxidant echinatin licochalcone A 1,1-dimethyl-2-propenyl α,α-dimethyl-β-propenyl radical adduct formation dimer |
| title | Antioxidant Mechanisms of Echinatin and Licochalcone A |
| title_full | Antioxidant Mechanisms of Echinatin and Licochalcone A |
| title_fullStr | Antioxidant Mechanisms of Echinatin and Licochalcone A |
| title_full_unstemmed | Antioxidant Mechanisms of Echinatin and Licochalcone A |
| title_short | Antioxidant Mechanisms of Echinatin and Licochalcone A |
| title_sort | antioxidant mechanisms of echinatin and licochalcone a |
| topic | antioxidant echinatin licochalcone A 1,1-dimethyl-2-propenyl α,α-dimethyl-β-propenyl radical adduct formation dimer |
| url | https://www.mdpi.com/1420-3049/24/1/3 |
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