Tea is popular worldwide, and is second only to water in consumption with 3.5 million tons produced each year. Wu long tea, also called oolong tea, comes from the camellia sinensis plant, just as black and green teas do. It is semi-fermented in contrast to black tea which is fully fermented and green tea which is not fermented, according to "Tea and Tea Products: Chemistry and Health Promoting Properties," by Chi-Tang Ho, Jen-Kun Lin and Fereidoon Shahidi. More than 400 chemical ingredients have been identified in the tea leaves of this plant.
Polyphenols
Wu long tea contains polyphenols. This ingredient accounts for up to 40 percent of the tea's dried weight. Polyphenols are chemicals that have powerful antioxidant properties. Antioxidants fight free radicals that cause damage to cells. The antioxidant effects in polyphenols, in fact, appear to be greater than those in Vitamin C, according to University of Maryland Medical Center. Polyphenols in wu long tea are classified as catechins. Teas derived from the camellia sinensis plant have six main catechin compounds. They are catechin, epicatechin, epicatechin gallate, epigallocatechin, gallaogatechin and apigallocatechin gallate, which also is known as EGCG. EGCG is the most active component and also the most studied.
Theaflavins and Thearubigens
As wu long undergoes the process of oxidizing, or fermenting, its catechins begin convert to theaflavins and thearubigens. In black tea, teaflavins determine the flavor and quality and thearubigens are responsible for the dark color. Since wu long tea is oxidized for a shorter time, it still has considerable amounts of polyphenols along with having theaflavins and thearubigens, according to "Phytochemicals and Bioactive Agents," by Wayne R. Bidlack. This combination, along with the tea's caffeine content, may make wu long an effective weight loss aid, according to "Obesity: Epidemiology, Pathophysiology and Prevention," by Debasis Bagchi and Harry G. Preuss.
Alkaloids
Wu long tea and others made from the camellia sinensis plant contain several alkaloids. These include theobromine, theophylline and caffeine, which cause the tea's stimulant effects, according to UMMC.
Amino Acids
Several amino acid compounds are found in wu long tea, according to Bidlack. L-theanine is among the most studied due to potential calming effects on the nervous system, according to UMMC.
References
- "Tea and Tea Products: Chemistry and Health Promoting Properties;" Chi-Tang Ho, Jen-Kun Lin and Fereidoon Shahidi; 2008
- "Liquid Jade;" Beatrice Hohenegger; 2006; page 202
- "Phytochemicals and Bioactive Agents;" Wayne R. Bidlack; 2000
- "Obesity: Epidemiology, Pathophysiology and Prevention," by Debasis Bagchi and Harry G. Preuss; 2007; pages 407-409
- University of Maryland Medical Center: Green tea
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