**5. Conclusions**

In conclusion, teas here studied possessed remarkably high antioxidant capacities regarding ferric-reducing and free radical-scavenging capacities. In addition, eight catechins, ca ffeine, theaflavine, and several other phenolic compounds, including gallic acid, chlorogenic acid, ellagic acid, and kaempferol-3- *O*-glucoside, were detected in these Chinese teas. Compared with dark, black, and white teas, green, yellow, and oolong teas exerted stronger antioxidant capacity and contained more polyphenols, especially catechins like epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate. Overall, tea is a good natural source of dietary antioxidant phytochemicals, and can be used to produce food additives, functional foods, nutraceuticals, and cosmetics.

**Author Contributions:** Conceptualization, R.-Y.G. and H.-B.L.; Data curation, C.-N.Z.; Formal analysis, G.-Y.T.; Funding acquisition, R.-Y.G. and H.-B.L.; Investigation, G.-Y.T., C.-N.Z., X.-Y.X., S.-Y.C., Q.L., A.S. and Q.-Q.M.; Methodology, G.-Y.T., C.-N.Z. and H.-B.L.; Project administration, R.-Y.G. and H.-B.L.; Resources, G.-Y.T.; Software, G.-Y.T.; Supervision, R.-Y.G. and H.-B.L.; Validation, G.-Y.T., C.-N.Z., R.-Y.G. and H.-B.L.; Visualization, C.-N.Z.; Writing—original draft, G.-Y.T. and C.-N.Z.; Writing—review & editing, R.-Y.G. and H.-B.L.

**Funding:** This work was supported by the National Key R&D Program of China (2018YFC1604400); Shanghai Basic and Key Program (18JC1410800); Shanghai Pujiang Talent Plan (18PJ1404600).

**Conflicts of Interest:** The authors declare no conflict of interest.
