Antimicrobial Properties of Freeze-Dried Hyaluronic Acid Sheets Containing Persimmon Tannin

Oral mucositis is a frequent adverse effect of cancer therapy and is often complicated by pain, oral dryness, and secondary infection. Freeze-dried hyaluronic acid (HA) sheets can protect and moisturize the oral mucosa, but their intrinsic antibacterial activity is limited. We developed freeze-dried HA sheets containing the commercial persimmon tannin product PANCIL® PS-M and evaluated their release behavior, pH profile, antimicrobial activity, and in vitro cytocompatibility. Persimmon tannin release into phosphate-buffered saline was quantified over 8 h using the Folin–Ciocalteu method. Antimicrobial activity against Streptococcus mitis, Prevotella intermedia, and Candida albicans was assessed by colony counting, and cytocompatibility was evaluated using the human oral cell line T3M-1. Approximately 95% of the incorporated persimmon tannin was released within 8 h, while the surrounding pH remained near neutral to mildly alkaline. The antibacterial HA sheets markedly reduced viable counts of S. mitis and P. intermedia, whereas no inhibitory effect was observed against C. albicans. Neither HA sheet nor antibacterial HA sheet solutions significantly reduced T3M-1 cell viability at concentrations up to 100 µg/mL after 24 h. These findings suggest that persimmon tannin-containing HA sheets may provide sustained antibacterial activity without detectable cytotoxicity under the tested conditions and may serve as a topical adjunct for cancer treatment-related oral mucositis.