Oriental beech (Fagus orientalis L.) steaming condensate: phenolic composition and functional activities

This study presents a comprehensive investigation of the bioactive properties of the condensate formed during the steaming treatment of beech wood (Fagus orientalis L.). The phenolic compound profile, antioxidant capacity, enzyme inhibition, and antimicrobial activity of the condensate were evaluated using multiple analytical methods. Rich in total phenolic content (339.20 mg GAE/g) and flavonoid levels (79.74 mg QE/g), the condensate exhibited strong reducing power in the ferric reducing antioxidant power assay (FRAP), while demonstrating moderate radical scavenging activity in the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis (3-ethylbenzothiazoline 6-sulfonic acid)) tests. In antimicrobial assessments, the condensate was found to be effective against Gram-positive bacteria, Staphylococcus aureus and Bacillus cereus as well as Candida albicans as a pathogen fungus, while showing lower activity against Gram-negative bacteria. Its antifungal efficacy was found to be notable when compared to nystatin. Although the IC₅₀ value of the condensate in α-amylase inhibition assays (1320.00 µg/mL) was weaker than that of the reference inhibitor acarbose (33.26 µg/mL), the results indicate its potential as a plant-based enzyme inhibitor candidate. Fourier transform infrared (FTIR) spectroscopy revealed characteristic peaks associated with lignin derivatives, carbohydrates, and ester bonds in the condensate. LC–MS/MS analyses identified chlorogenic acid (1581.65 µg/g) as the major phenolic compound, along with ferulic acid and rosmarinic acid. Beech steaming condensate stands out as a valuable bioactive resource in the context of industrial by-product valorization. With its antioxidant, antimicrobial, and enzyme-inhibitory properties, it holds promising potential for applications in the food preservation, pharmaceutical, and cosmetic industries. These findings may contribute to the sustainability of the forest industry from a circular economy perspective.