Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce
Tyrosinase inhibitors are capable of preventing unfavorable enzymatic browning of fruits and vegetables. In this study, the capacity of <i>Acacia confusa</i> stem bark proanthocyanidins (ASBPs) to inhibit tyrosinase activity was evaluated. ASBPs were shown to be a high-potential inhibito...
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MDPI AG
2023-04-01
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| author | Guanghui Li Yaying Zhao Zeya Qin Shudong Wei Dandan Liang Yun Liang Wei Song Baomiao Ding |
| author_facet | Guanghui Li Yaying Zhao Zeya Qin Shudong Wei Dandan Liang Yun Liang Wei Song Baomiao Ding |
| author_sort | Guanghui Li |
| collection | DOAJ |
| description | Tyrosinase inhibitors are capable of preventing unfavorable enzymatic browning of fruits and vegetables. In this study, the capacity of <i>Acacia confusa</i> stem bark proanthocyanidins (ASBPs) to inhibit tyrosinase activity was evaluated. ASBPs were shown to be a high-potential inhibitor of tyrosinase with IC<sub>50</sub> values of 92.49 ± 4.70 and 61.74 ± 8.93 μg/mL when using L-tyrosine and L-DOPA as the substrate, respectively. The structural elucidation performed with UV-vis, FT-IR spectroscopy, ESI-MS and thiolysis coupled to HPLC-ESI-MS suggested that ASBPs had structural heterogeneity in monomer units and interflavan linkages and consisted mainly of procyanidins dominant with B-type linkages. To gain insights into the inhibitory mechanisms of ASBPs against tyrosinase, different spectroscopic and molecular docking methods were further conducted. Results validated that ASBPs possessed the ability to chelate copper ions and could prevent the oxidation process of substrates by tyrosinase. The hydrogen bond formed with Lys-376 residue played a key role in the binding force of ASBPs with tyrosinase that induced a certain alteration in the microenvironment and secondary structure of tyrosinase, resulting in the enzymatic activity being ultimately restricted. It was also observed that ASBPs treatment effectively inhibited the activities of PPO and POD to retard the surface browning of fresh-cut asparagus lettuce and thus extended their shelf-life. The results provided preliminary evidence supporting the exploitation of ASBPs into potential antibrowning agents for the fresh-cut food industry. |
| first_indexed | 2024-03-11T04:41:36Z |
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| last_indexed | 2024-03-11T04:41:36Z |
| publishDate | 2023-04-01 |
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| series | Molecules |
| spelling | doaj.art-898000a163fd444b98379c199985dcc22023-11-17T20:38:55ZengMDPI AGMolecules1420-30492023-04-01288343510.3390/molecules28083435Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus LettuceGuanghui Li0Yaying Zhao1Zeya Qin2Shudong Wei3Dandan Liang4Yun Liang5Wei Song6Baomiao Ding7College of Life Science, Yangtze University, Jingzhou 434025, ChinaCollege of Life Science, Yangtze University, Jingzhou 434025, ChinaCollege of Life Science, Yangtze University, Jingzhou 434025, ChinaCollege of Life Science, Yangtze University, Jingzhou 434025, ChinaCollege of Life Science, Yangtze University, Jingzhou 434025, ChinaCollege of Life Science, Yangtze University, Jingzhou 434025, ChinaCollege of Life Science and Engineering, Henan University of Urban Construction, Pingdingshan 467036, ChinaCollege of Life Science, Yangtze University, Jingzhou 434025, ChinaTyrosinase inhibitors are capable of preventing unfavorable enzymatic browning of fruits and vegetables. In this study, the capacity of <i>Acacia confusa</i> stem bark proanthocyanidins (ASBPs) to inhibit tyrosinase activity was evaluated. ASBPs were shown to be a high-potential inhibitor of tyrosinase with IC<sub>50</sub> values of 92.49 ± 4.70 and 61.74 ± 8.93 μg/mL when using L-tyrosine and L-DOPA as the substrate, respectively. The structural elucidation performed with UV-vis, FT-IR spectroscopy, ESI-MS and thiolysis coupled to HPLC-ESI-MS suggested that ASBPs had structural heterogeneity in monomer units and interflavan linkages and consisted mainly of procyanidins dominant with B-type linkages. To gain insights into the inhibitory mechanisms of ASBPs against tyrosinase, different spectroscopic and molecular docking methods were further conducted. Results validated that ASBPs possessed the ability to chelate copper ions and could prevent the oxidation process of substrates by tyrosinase. The hydrogen bond formed with Lys-376 residue played a key role in the binding force of ASBPs with tyrosinase that induced a certain alteration in the microenvironment and secondary structure of tyrosinase, resulting in the enzymatic activity being ultimately restricted. It was also observed that ASBPs treatment effectively inhibited the activities of PPO and POD to retard the surface browning of fresh-cut asparagus lettuce and thus extended their shelf-life. The results provided preliminary evidence supporting the exploitation of ASBPs into potential antibrowning agents for the fresh-cut food industry.https://www.mdpi.com/1420-3049/28/8/3435<i>Acacia confusa</i>proanthocyanidinstyrosinase inhibitionconformational changefresh-cut asparagus lettuce |
| spellingShingle | Guanghui Li Yaying Zhao Zeya Qin Shudong Wei Dandan Liang Yun Liang Wei Song Baomiao Ding Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce Molecules <i>Acacia confusa</i> proanthocyanidins tyrosinase inhibition conformational change fresh-cut asparagus lettuce |
| title | Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce |
| title_full | Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce |
| title_fullStr | Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce |
| title_full_unstemmed | Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce |
| title_short | Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from <i>Acacia confusa</i> Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce |
| title_sort | mechanistic understanding of tyrosinase inhibition by polymeric proanthocyanidins from i acacia confusa i stem bark and their effect on the browning resistance of fresh cut asparagus lettuce |
| topic | <i>Acacia confusa</i> proanthocyanidins tyrosinase inhibition conformational change fresh-cut asparagus lettuce |
| url | https://www.mdpi.com/1420-3049/28/8/3435 |
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