Variations of Antioxidant Properties and NO Scavenging Abilities during Fermentation of Tea

Yang Xu,Chun-Jie Li,Hang Zhao,Wei Shi,Jun Sheng,Xue-Zhen Lin,Min Zhang

doi:10.3390/ijms12074574

Abstract

Tea is known as one of the most popular beverages in the world, which is believed to be beneficial for health. The main components in tea will change a lot depending on the different processes of fermentation, and thus the effects of different teas on human health may differ. The aim of this study is to explore the varied abilities of reactive oxygen species (ROS) and nitric oxide (NO) scavenging during the fermentation of tea. In this study, we conducted the in vitro experiments which involved some reaction systems indicating the abilities of scavenging ROS and NO. We also investigated the effects of tea and their components (catechins, theabrownins, caffeine) on the intracellular levels of ROS and NO, using Raw 264.7 cells as the model. We found that regardless of whether it was out of cell system or in Raw 264.7 cells, the abilities of scavenging ROS would decrease during the fermentation of tea. Further, the post-fermented pu-erh tea showed the best effect on inhibiting the lipopolysaccharide (LPS)-induced production of NO. These findings indicated that the fermentation process caused a change of the components which might be due to the changes of their antioxidant properties and NO scavenging abilities.

Highlights

Tea is one of the most popular beverages
The polysaccharide levels were substantially higher in the fermented black tea and pu-erh tea, while the polyphenol level was higher in the unfermented green tea (Table 1)
The results acquired from chemical components and scavenging activity analysis in this study provide clues to the key molecules that contribute to the inhibition of reactive oxygen species (ROS) and Nitric oxide (NO) production

Summary

Introduction

Tea is one of the most popular beverages. Tea consumption is part of many people’s daily life, as an everyday drink and as a therapeutic aid in many illnesses. Tea is categorized into different types based on manufacturing process: unfermented tea (green tea), fully fermented tea (black tea) and post-fermented tea (pu-erh tea) [4,5]. The legendary medicinal properties are well established. These beneficial effects have been attributed to the presence of tea components such as catechins, polysaccharides, theabrownins and caffeine [6,7,8,9]. The chemical compositions of the tea in different forms were distinct and induced the change of the bioactivities, depending on the degree of fermentation and the various modes of preparation [10]

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Conclusion