Academic Journal
Mechanistic Insights into Polyphenol Oxidase Inhibition by Four Bioactive Constituents from Hydrangea macrophylla Serrata: Antioxidant Activity of Single Compounds Compared to the Whole-Leaf Extract.
| Title: | Mechanistic Insights into Polyphenol Oxidase Inhibition by Four Bioactive Constituents from Hydrangea macrophylla Serrata: Antioxidant Activity of Single Compounds Compared to the Whole-Leaf Extract. |
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| Authors: | Mei S; Institute of Nutritional Sciences, Friedrich Schiller University Jena, 07743 Jena, Germany., Heymann T; Institute of Chemistry-Food Chemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany., Böhm V; Institute of Nutritional Sciences, Friedrich Schiller University Jena, 07743 Jena, Germany. |
| Source: | Molecules (Basel, Switzerland) [Molecules] 2026 Sep 24; Vol. 31 (19). Date of Electronic Publication: 2026 Sep 24. |
| Publication Type: | Journal Article |
| Language: | English |
| Journal Info: | Publisher: MDPI Country of Publication: Switzerland NLM ID: 100964009 Publication Model: Electronic Cited Medium: Internet ISSN: 1420-3049 (Electronic) Linking ISSN: 14203049 NLM ISO Abbreviation: Molecules Subsets: MEDLINE |
| Imprint Name(s): | Original Publication: Basel, Switzerland : MDPI, c1995- |
| MeSH Terms: | Antioxidants*/chemistry , Antioxidants*/pharmacology , Plant Extracts*/chemistry , Plant Extracts*/pharmacology , Plant Leaves*/chemistry , Catechol Oxidase*/antagonists & inhibitors , Catechol Oxidase*/chemistry , Hydrangea*/chemistry , Enzyme Inhibitors*/chemistry , Enzyme Inhibitors*/pharmacology, Chlorogenic Acid/chemistry ; Chlorogenic Acid/pharmacology ; Phenols/chemistry ; Molecular Docking Simulation |
| Abstract: | Hydrangea macrophylla serrata (tea-hortensia) leaves are traditionally used to produce a sweet herbal tea ("Amacha") and contain hydroxycinnamates and dihydroflavonols with potential bioactivities (e.g., anti-inflammatory, anti-allergy). In this study, from an extract of tea-hortensia leaves, we isolated and structurally characterized four major constituents: chlorogenic acid (CGA, 5-caffeoylquinic acid), hydrangenol (HG), hydrangeic acid (HGA), and phyllodulcin (PD). The four constituents and the extract were evaluated for antioxidant capacity via total phenolic content (TPC), ABTS radical scavenging (TEAC: Trolox equivalent antioxidant capacity), and oxygen radical absorbance capacity (ORAC) assays, and for anti-browning potential via polyphenol oxidase (PPO) inhibition assays. To elucidate the underlying mechanisms, we employed kinetic analysis to determine inhibition types, evaluated copper-chelating capacity, and performed molecular docking simulations to investigate ligand-PPO binding modes and key interacting residues. The tea extract exhibited significantly superior antioxidant capacity compared to all isolated compounds across all assays, with CGA being the most potent among the four compounds. For anti-browning activity, CGA and PD showed the strongest PPO inhibition (90%), while the tea extract (83% at 2 mg/mL) outperformed HG and HGA but was less potent than CGA and PD. Molecular docking further revealed that CGA formed stable interactions with key residues in the PPO active site. These findings provide a systematic comparative assessment of the anti-browning mechanisms of the major constituents of H. macrophylla serrata, highlighting the potential of this plant as a natural source of antioxidants and anti-browning agents for food applications. The integration of biochemical kinetics, copper-chelating analysis, and in silico docking offers a comprehensive mechanistic framework for understanding PPO inhibition by natural phenolic compounds. |
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| Contributed Indexing: | Keywords: Hydrangea macrophylla; anti-browning activity; antioxidant activity; chlorogenic acid; hydrangeic acid; hydrangenol; molecular docking; phyllodulcin |
| Substance Nomenclature: | 0 (Antioxidants) 0 (Plant Extracts) EC 1.10.3.1 (Catechol Oxidase) 0 (Enzyme Inhibitors) 318ADP12RI (Chlorogenic Acid) 0 (Phenols) |
| Entry Date(s): | Date Created: 20261016 Date Completed: 20261016 Latest Revision: 20261020 |
| Update Code: | 20261020 |
| PubMed Central ID: | PMC13666256 |
| DOI: | 10.3390/molecules31193411 |
| PMID: | 42883176 |
| Database: | MEDLINE |
| ISSN: | 1420-3049 |
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| DOI: | 10.3390/molecules31193411 |