Polyphenol Content and Antioxidant Capacity of Herbal Tea from Vietnamese Water Hyssop (Bacopa monnieri)

Abstract

A sustainable process to produce herbal tea from Vietnamese water hyssop (Bacopa monnieri) has been conducted. The product can be used as traditional Ayuvedic medicinal herb. In this study, factors affecting drying process have been investigated including temperature ranging from 60 to 80°C, material thickness from 0.18 to 0.54 g/cm² and air velocity from 0.5 to 1.5 m/s. Total polyphenols and soluble solid contents were observed during the process. Antioxidant capacity of raw and dried water hyssop have been also evaluated. The optimum result showed that at temperature of 60°C, material thickness of 0.18 g/cm² and air velocity of 1.5 m/s, polyphenols content and total soluble solids in final herbal tea were found at 15.13 mg/g gallic acid equivalent and 4.00%. With saponins concentrations of 0.53% and 0.50%, the IC50 values of 3.94 µg/ml and 4.45 µg/ml were found in the raw and dried water hyssop tea, respectively. It’s required to dry water hyssop at optimum condition in 180 minutes and chop materials into 1mm lengths before being used as herbal tea.