Phytochemical Profiles and Antioxidant Activity of Different Varieties of Adinandra Tea (Adinandra Jack)

Consumption of plant foods has been negatively associated with the risk of developing chronic diseases, which is partly attributed to their rich and diverse phytochemicals. To promote the rational and effective application of Adinandra tea (Adinandra Jack), a traditional Chinese tea (Shiyacha) widely consumed as a health beverage, the complete phytochemical profile and antioxidant activity of four varieties of Adinandra tea were analyzed. They were rich in phenolics and flavonoids, ranging from 71.29 to 140.54 mg of gallic acid equivalent/g and from 19.13 to 88.72 mg of catechin equivalent/g, respectively. Their antioxidant capacities were high, as revealed by oxygen radical absorbance capacity, peroxyl radical scavenging capacity, and cellular antioxidant activity (CAA) assays. An obvious antiproliferation effect was observed in HepG2 and MCF-7 cells, with EC50 ranging from 1.05 to 6.44 mg/mL and from 2.26 to 8.02 mg/mL, respectively. Among the four varieties compared, Nitida and Millettii had a higher CAA value and antiproliferation activity, while Latifolia contained considerable bound phenolics.