Hydrolysis Modification of Tannic Acid as a Biocidal and Antioxidant Agent with Low Cytotoxicity

다국어 초록 (Multilingual Abstract)

Tannic acid (TA) is a polyphenolic hydrolyzable tannin having several biological properties. However, the application of TA is limited to its performance, rendering it essential to modify TA to increase its practical applications. This study reports the facile modification of TA by thermal and hydrolysis treatments using autoclave and hydrothermal reactor, respectively. The structures of thermally treated TA (TTA) and hydrolyzed TA (HTA) were determined by FTIR and ¹H NMR. The results confirmed the partial conversion of TTA and complete conversion of HTA into gallic acid and pyrogallol, respectively. TTA and HTA showed improved antimicrobial activity, potent antioxidant activity, and lower cytotoxicity than TA. However, HTA exhibited the highest antimicrobial activity because of the high surface area and cell interaction. Compared to TA and TTA, HTA demonstrated a better antioxidant activity and lower cytotoxicity owing to the steric hindrance and lesser interaction between human cells and pyrogallol. Thus, HTA with potent functional properties can be prepared by a facile processing method and employed as an additive for food packaging and biomedical applications.