Optimisation of the process of acquiring tannin compounds with anti - Vibrio parahaemolyticus from the leaves of sea almond tree (Terminalia catappa L.)

Abstract

Terminalia catappa L. (so-called Bang in Vietnamese) is considered an important medicinal plant in folk medicine for
the treatment of digestive disorders and other inflammatory conditions. This plant contains several medicinally essential components, especially the tannin group. This study evaluated a number of factors affecting tannin extraction from the leaves of sea almond tree with the help of response surface methodology (RSM). The factors used to evaluate are solvent concentration, solvent:material ratio (v/w) and soaking time (hours). Research results show that the highest total tannin content (TTC) is 1.54 mg GAE/g raw material, the optimal conditions are determined as follows: ethanol 54%, solvent:material ratio (S:MR) is 41:1 (v/w) and soaking time 2 hours. The experimental values (TTC=1.54±0.02 mg TAE/g raw material) show good agreement with the predicted value (TTC=1.54 mg TAE/g raw material). Experiments evaluating antibacterial activity show that the optimal extract of sea almond tree leaves has the ability to resist Vibrio parahaemolyticus bacteria. The results of this study could pave the way for the mass production of medicinal compounds containing tannins from sea almond tree leaves and improve the usage value of this popular plant.