Wound-healing, anti-inflammatory, and antioxidant activities of β-glucan from red sea-mangroves-associated Candida tropicalis.

Marine yeasts are underexplored resource for bioactive polysaccharides with potential pharmaceutical activities. In this study, five marine yeast isolates from mangrove shrubs were screened for β-glucan production. Isolate Y4 exhibited the highest β-glucan yield, reaching 17.11% of cell fresh weight- approximately 1.57-fold higher than Saccharomyces cerevisiae. Molecular identification revealed Y4 to be Candida tropicalis AUMC 15,533 through ITS rRNA sequencing and phylogenetic analysis. Structural characterization using ¹H NMR and FT-IR confirmed the presence of β-1,3 and β-1,6 glucan linkages. Optimization of β-glucan production via Plackett–Burman design identified glucose, yeast extract, shaking speed, and incubation time as critical factors, achieving a maximum yield of 0.42 g/100 mL. The extracted β-glucan demonstrated significant biological activities, including antioxidant capacity (IC₅₀= 18.31 µg/mL), wound healing efficacy (80.19% closure in 24 h), and anti-inflammatory effects, as evidenced by reduced expression of pro-inflammatory cytokines TNF-α (74.5% reduction) and IL-6 (80.8% reduction). Carboxymethylated β-glucan showed lower but still substantial activity across all assays. These findings highlight the superior biosynthetic capacity of marine C. tropicalis for β-glucan production and its potential therapeutic properties. This study underscores the importance of exploring marine microbial diversity for potential bioactive molecules with biomedical applications.