There are two popular varieties of this tea Camellia sinensis var assamica and Camellia sinensis var sinensis.
The beverage has a long and rich history, dating back thousands of years. The Camellia sinensis plant is native to the mountainous regions of China. It is believed to have originated in the Yunnan province in the country’s southwest. Legend has it that the Chinese emperor Shen Nong discovered the herb in 2737 BCE when some tea leaves accidentally fell into his cup of hot water. It became a popular beverage in China during the Tang dynasty (618-907 CE). During this time, tea was consumed in loose-leaf form and was brewed in teapots made of ceramic or clay. Tea drinking became an important social and cultural activity, and the tea ceremony was developed to enjoy the beverage.
The herb to other countries began during the Tang dynasty. It was first introduced to Japan in the 9th century by Japanese Buddhist monks who had visited China. In the 16th century, Portuguese traders brought tea to Europe, and it became popular in Britain in the 17th century. The British East India Company began importing tea from China in the 17th century, and it became an important part of British culture. The British eventually began growing tea in India and other parts of the British Empire, which led to the development of the Indian tea industry. Many of the tea gardens in India were started during colonial times. Today, tea is produced in many countries worldwide, including China, India, Sri Lanka, Kenya, and Japan. It is grown in various climates and environments, and there are many different types and flavors of the herb available, including black, green, oolong, and herbal tea.
The most well-known chemical constituent, caffeine, is stimulating. Caffeine is approximately 4 percent in dry weight. Tannin is the other principal constituent. Caffeine, theobromine, and theophylline are polyphenols belonging to the phenolic group of compounds. These chemical compounds help defend the plant against insects and pests. Theobromine and theophylline are responsible for the bitterness of this brew.
Theanine in green tea plays a role in reducing stress. Oxidized catechins (theaflavins in black tea) reduce cholesterol levels in the blood. The herb decreases lipid and carbohydrate absorption, increases lipid metabolism, inhibits de novo metabolic production of fat, and increases carbohydrate utilization. (Grove et al., 2010) Green tea intake is associated with increased weight loss due to diet-induced heat generation attributed to the catechin epigallocatechin gallate. (Shixian et al., 2006)
High caffeine intake was associated with weight loss through heat and fat oxidation and suppressed leptin in women. (Leptin is a molecule that triggers a signal of satiation to the brain).