Phenolic Content and Antioxidant Capacity of Native Teas

Green tea (GT), made from Camellia sinensis (L.) Kuntze, is a rich source of phenolic compounds and has high antioxidant capacity. Regular consumption of GT has been linked to various health benefits, including lowering cholesterol, weight loss, etc., and therefore interest in GT has been steadily increasing. Despite current popularity among consumers, domestic production of GT is confined to South Carolina and Hawaii, and thus consumption largely depends on imported tea. Aside from GT, various species have been used for tea. Of those, spicebush (Lindera benzoin (L.) Blume) is native to the eastern part of the U.S. from Maine to Texas, and Navajo tea (Thelesperma megapotamicum (Spreng. ) Kuntze) is distributed mostly in the western part of the U.S. from Oregon to Michigan. The objective of the study was to compare phenolic content and antioxidant capacity of GT to those of teas made from two native species that can be grown in many parts of the U.S. Folin-Ciocalteu assay was performed to determine phenolic content of all three teas, using gallic acid as a standard. Phenolic content of these teas were 19.0 (GT), 1.7 (spicebush tea, ST), 4.6 (Navajo tea, NT) in mg of gallic acid equivalent per 100 g of dry weight. Similarly, Ferric Reducing Antioxidant Power (FRAP) assay was performed to assess antioxidant capacity of these teas, which were determined as 1068.1 (GT), 34.1 (ST), and 263.2 (NT) expressed in umol of Trolox equivalent per g of dry weight. While phenolic content and antioxidant capacity of two native teas were less than those of GT, domestic production of these teas potentially creates potential opportunities for both farmers and health-conscious consumers.