Targeted and untargeted metabolomic analyses and biological activity of Tibetan tea

Tibetan tea is not only a national product of geographical identity, but also a traditional beverage inherits Chinese tradition. This study evaluated the metabolic profiles and biological activity in four Tibetan teas. 83 nonvolatile metabolites were identified as differentially expressed metabolites, including amino acids and their derivatives, phenolic acids, flavonoids, nucleotides and their derivatives, terpenes, alkaloids, organic acids, lipids and others. CC and 131 were rich in terpenoids and lipids. MZ contained the highest contents of amino acids and their derivatives, phenolic acids and flavonoids. 26 key volatile compounds were considered as odor-active compounds. MZ showed the highest level of antioxidant and hypoglycemic activity. Statistics analysis indicated that polyphenols, flavonoids and catechins were significantly correlated (|r| >= 0.7, P < 0.05) with biological activities. This study indicated significant differences in the metabolic profiles of various types of Tibetan tea, which provided a clear database for quality detection of Tibetan tea.