Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study
As a valuable traditional Chinese herbal medicine, Radix Astragali has attracted much attention due to its extensive pharmacological activities. In this study, density functional theory (DFT) was used thermodynamically and kinetically in detail to predict the antioxidant activity and reaction mechan...
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MDPI AG
2023-06-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/13/5039 |
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| author | Xiao-Qin Lu Shu Qin Jindong Li |
| author_facet | Xiao-Qin Lu Shu Qin Jindong Li |
| author_sort | Xiao-Qin Lu |
| collection | DOAJ |
| description | As a valuable traditional Chinese herbal medicine, Radix Astragali has attracted much attention due to its extensive pharmacological activities. In this study, density functional theory (DFT) was used thermodynamically and kinetically in detail to predict the antioxidant activity and reaction mechanisms involved in the free radical scavenging reactions of three representative isoflavonoids (formononetin, calycosin, and calycosin-7-glucoside) extracted from Radix Astragali. Three main mechanisms, including hydrogen atom transfer (HAT), proton transfer after electron transfer (SET-PT), and sequential proton loss electron transfer (SPLET) were examined by calculating the thermodynamic parameters. It was found that HAT is the predominant mechanism in the gas phase, while SPLET is supported in the solvent environment. The isoflavonoids’ order of antioxidant activity was estimated as: calycosin > calycosin-7-glucoside > formononetin. For the calycosin compound, the result revealed the feasibility of double HAT mechanisms, which involve the formation of stable benzodioxazole with significantly reduced energy in the second H<sup>+</sup>/e<sup>−</sup> reaction. In addition, the potential energy profiles and kinetic calculations show that the reaction of <sup>•</sup>OH into the 3′-OH site of calycosin has a lower energy barrier (7.2 kcal/mol) and higher rate constant (4.55 × 10<sup>9</sup> M<sup>−1</sup> s<sup>−1</sup>) compared with other reactions in the gas phase. |
| first_indexed | 2024-03-11T01:34:15Z |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-11T01:34:15Z |
| publishDate | 2023-06-01 |
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| series | Molecules |
| spelling | doaj.art-7977186f8dd64645a2c020753c8c95892023-11-18T17:07:17ZengMDPI AGMolecules1420-30492023-06-012813503910.3390/molecules28135039Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical StudyXiao-Qin Lu0Shu Qin1Jindong Li2Shanxi Center for Testing of Functional Agro-Products, Shanxi Agricultural University, Taiyuan 030031, ChinaShanxi Center for Testing of Functional Agro-Products, Shanxi Agricultural University, Taiyuan 030031, ChinaShanxi Center for Testing of Functional Agro-Products, Shanxi Agricultural University, Taiyuan 030031, ChinaAs a valuable traditional Chinese herbal medicine, Radix Astragali has attracted much attention due to its extensive pharmacological activities. In this study, density functional theory (DFT) was used thermodynamically and kinetically in detail to predict the antioxidant activity and reaction mechanisms involved in the free radical scavenging reactions of three representative isoflavonoids (formononetin, calycosin, and calycosin-7-glucoside) extracted from Radix Astragali. Three main mechanisms, including hydrogen atom transfer (HAT), proton transfer after electron transfer (SET-PT), and sequential proton loss electron transfer (SPLET) were examined by calculating the thermodynamic parameters. It was found that HAT is the predominant mechanism in the gas phase, while SPLET is supported in the solvent environment. The isoflavonoids’ order of antioxidant activity was estimated as: calycosin > calycosin-7-glucoside > formononetin. For the calycosin compound, the result revealed the feasibility of double HAT mechanisms, which involve the formation of stable benzodioxazole with significantly reduced energy in the second H<sup>+</sup>/e<sup>−</sup> reaction. In addition, the potential energy profiles and kinetic calculations show that the reaction of <sup>•</sup>OH into the 3′-OH site of calycosin has a lower energy barrier (7.2 kcal/mol) and higher rate constant (4.55 × 10<sup>9</sup> M<sup>−1</sup> s<sup>−1</sup>) compared with other reactions in the gas phase.https://www.mdpi.com/1420-3049/28/13/5039antioxidant mechanismradical scavenging reactionisoflavonoidsDFTstructure-activity relationship |
| spellingShingle | Xiao-Qin Lu Shu Qin Jindong Li Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study Molecules antioxidant mechanism radical scavenging reaction isoflavonoids DFT structure-activity relationship |
| title | Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study |
| title_full | Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study |
| title_fullStr | Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study |
| title_full_unstemmed | Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study |
| title_short | Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study |
| title_sort | radical scavenging capability and mechanism of three isoflavonoids extracted from radix astragali a theoretical study |
| topic | antioxidant mechanism radical scavenging reaction isoflavonoids DFT structure-activity relationship |
| url | https://www.mdpi.com/1420-3049/28/13/5039 |
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