“…The former refers to the condensation products of hydroxyflavanes, which are interconnected by C-C bonds and are not easy to decompose in water, while the latter is an ester whose ester bond is easy to hydrolyze under the action of alkali, enzyme or acid. Tannin can react with enzymes and metal ions, and is able to combine with proteins, generating pharmacological effects on convergence, anti-inflammation, sedation, anticoagulation, anti-oxidation, and anti-tumor (Manzoor et al, 2022;Ha et al, 2022;Das et al, 2020;Fraga-Corral et al, 2020). What's more, its extensive application can be observed in other various aspects including tanning agents' adhesives, additives, preservatives, and water treatment (Das et al, 2020;Guo et al, 2020).…”