Natural Polyphenol Oxidase Inhibitors from Glochidion perakense: LC-MS/MS Identification, In Silico Binding Analysis and Chitosan Microencapsulation for Food Preservation Applications

Plant-derived polyphenolic compounds offer natural alternatives for polyphenol oxidase (PPO) inhibition to prevent enzymatic browning in fresh-cut produce. However, their application is limited by poor stability and environmental sensitivity. This study screened nine Southeast Asian plant species for natural PPO inhibition and developed chitosan-based microencapsulation to enhance extract stability. Systematic evaluation revealed Glochidion perakense leaves exhibited exceptional antioxidant capacity (88.11% DPPH scavenging; IC50 = 3.04 ± 0.17 µg/mL) and superior PPO inhibitory activity (89.93% inhibition; IC50 = 278.00 ± 2.04 µg/mL), showing better enzyme inhibition than commercial kojic acid (IC50 = 311.58 ± 1.83 µg/mL). This represents the first comprehensive phytochemical characterization of G. perakense for food preservation applications. LC-MS/MS analysis identified 23 bioactive compounds, with molecular docking studies revealing (-)-amurensisin as the key inhibitor showing strongest PPO binding affinity (ΔG = –7.13 kcal/mol) compared to reference tropolone (ΔG = –5.20 kcal/mol). Chitosan microencapsulation at 1:1 chitosan-to-extract ratio (w/w) significantly improved extract stability, maintaining 4-fold higher phenolic content during 30-day storage compared to unencapsulated controls. Validation studies using fresh-cut potatoes demonstrated encapsulated extract achieved 2.5-fold superior PPO inhibition versus free extract. These findings establish G. perakense as a promising natural preservative and demonstrate microencapsulation as an effective delivery system for extending fresh-produce shelf life while addressing post-harvest losses in the food industry. HIGHLIGHTS First comprehensive phytochemical characterization of Glochidion perakense identifying 23 bioactive compounds with superior polyphenol oxidase (PPO) inhibitory activity compared to commercial kojic acid. Molecular docking identified multiple potent PPO inhibitors including (-)-amurensisin (–7.13 kcal/mol), catechin (–6.36 kcal/mol), and bergenin (–5.84 kcal/mol), all surpassing reference tropolone (–5.20 kcal/mol) with high binding stability. Novel chitosan microencapsulation enhanced extract stability 4-fold and improved anti-PPO efficacy 2.5-fold in fresh-cut applications. GRAPHICAL ABSTRACT