Phenolic content in tea green tea. Catechins constitute about 25% of the dry mass of a fresh tea leaf, although total catechin content varies widely depending on species, clonal variation, growing location, season, light variation, and altitude. They are present in nearly all teas made from "Camellia sinensis", including white tea, green tea, black tea and oolong tea. Of all the catechins in tea, EGCG is the main subject of scientific study with regard to its potential health effects. 4-Hydroxybenzoic acid, 3,4-dihydroxybenzoic acid (protocatechuic acid), 3-methoxy-4-hydroxy-hippuric acid and 3-methoxy-4-hydroxybenzoic acid (vanillic acid) are the main catechins metabolites found in humans after consumption of green
Assam tea provide him with samples of the leaves and seeds, which he planned to have scientifically examined. Robert Bruce died shortly thereafter, without having seen the plant properly classified. It was not until the early 1830s that Robert’s brother, Charles, arranged for a few leaves from the Assam tea bush to be sent to the botanical gardens in Calcutta for proper examination. There, the plant was finally identified as a variety of tea, or "Camellia sinensis" var "assamica", but different from the Chinese version ("Camellia sinensis" var. "sinensis"). The intervention of the colonizing British East India Company was realised through a