Purple tea, like all other tea originates from the Camellia Sinensis plant. The same plant that we get our familiar black and green tea from.
Purple tea is grown mainly in kenya. It's grown at elevations between 4,500 and 7,500 feet. This high altitude near the equator results in higher levels of UV bombardment, and causes the plants to produce very high levels of anti-oxidants to protect the leaves from damage. The purple appearance of the tea is caused by a unique genetic mutation which produces anthocyanin, the same powerful anti-oxidant found in blueberries. In fact, it contains 1.5 percent compared to .1 percent for blueberries.
Anthocyanin has many medicinal properties and is particularly known to be beneficial against cardiovascular diseases. These anti-oxidants are known to provide anti-cancer benefits, improve vision, and aid in cholesterol and blood sugar metabolism. At the same time, caffeine content is lower than that of black or green tea. Purple tea also contains higher amounts of another anti-oxidant - polynols. More than black or green teas (16.5 percent versus 10.1 percent for black and 9.1 for green).