UPLC-Q-Exactive-MS based metabolomics reveals chemical variations of three types of insect teas and their in vitro antioxidant activities

Insect tea is a traditional health drink produced by the Miao, Dong and Yao ethnic minorities in southwest China. However, little information is available on the chemical differences of various insect teas. The present study aimed to comprehensively compare the chemical profiles of three typical insect teas (Hawk, Sanye and Huaxiang insect teas) using ultra-performance liquid chromatography coupled to Q Exactive hybrid quadrupole-Orbitrap mass spectrometry (UPLC-Q-Exactive-MS) based metabolomics approach and evaluate their antioxidant activities. Totally, 283 metabolites were tentatively identified. Multivariate analyses demonstrated that three types of insect teas significantly varied in metabolite distribution patterns, and 180 compounds were identified as potential biomarkers. Hawk samples were characterized by higher levels of flavonoids, whereas Huaxiang had higher contents of phenolic acids and amino acids. Moreover, Hawk also revealed the highest contents of total phenolics, and possessed the strongest 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) scavenging activity and ferric reducing antioxidant power. The well positive correlations were found between the antioxidant properties with their contents of phenolic compounds. These results indicate that insect teas are rich in phenolic compounds and could be used as promising source of natural antioxidants.