Comparative analysis of chemical constituents and antioxidant activity in tea-leaves microbial fermentation of seven tea-derived fungi from ripened Pu-erh tea

Abstract Ripened Pu-erh tea is a traditional microbial-fermented tea with multiple beneficial effects and the genus Aspergillus were considered as the dominant fungi. In this study, six Aspergillus and one Penicillium fungi, abbreviated as AniPT1, AsyPT2, ApaPT3, AsePT4, PmaPT5, AusPT6 and AtaPT7, were inoculated into sun-dried green tea-leaves for the microbial fermentation. Based on 42 chemical components belonging to several classes as polyphenols, amino acids and purine alkaloids, PCA and HCA revealed the significant differences in tea-leaves microbial fermentation of seven tea-derived fungi. Most of catechins, flavonoids and free amino acids were decreased highly significantly (p  l -methionine, l -tryptophan, l -cysteine, l -histidine and γ-aminobutyric acid, and the improvement of antioxidant activity in tea-leaves after inoculated fermentation. Particularly, AsyPT2 converted caffeine into theophylline mainly. The bivariate correlation analysis confirmed the extremely significantly (p