Tea comes from the plant Camellia sinensis and belongs to the Theaceae family. It is an evergreen shrub with lanceolate to obovate leaves and white or yellow flowers. The major chemical constituents of tea leaves are catechins, theaflavins, caffeine, tannins, theophylline, and volatile oils. Drinking tea has various health benefits including antioxidant effects, cardiovascular protection, cancer prevention, and reduced risk of obesity and Alzheimer's disease due to its anti-inflammatory and neuroprotective properties. Common adulterants of tea include substances like soapstone, gypsum, and dyes.

1. TEA
Sub- Pharmacognosy-II
By, Dhammadip Nandgaye
M Pharm
(Pharmaceutical Chemistry)

2. TEA
Biological source:
• The botanical name of tea is Camellia sinensis.
• The biological source of tea is prepared leaves and leaf buds of it.
• It belongs to the theaceae family.
• Commonly it is known as tea plant or tea shrub.

3. Morphological features:
• Tea is a evergreen shrub or small tree.
• It is usually trimmed to below 2 m during the cultivation of its leaves.
• It is consist of strong taproot.
• The color of flowers are yellow – white.
• The size of flower is 2.5-4 cm in diameter.
• Its flowers consist of 7 or 8 petals.
• The size of leaves are 4-15 cm long and 2-5 cm broad.
• The young , light green leaves have short and white hairs on the underside.
• Older leaves are deep green in color.
• The tea plant is polymorphic species.
• Its strong taproot giving rise to a surface mat of feeder roots with endotrophic
mycorrhizae.

4. • Leaves are alternate and lanceolate to obovate.
• Leaves are pubescent and sometimes become the glabrous, serrate,
acute or acuminate.
• Flowers are having 1-3 in number.
• Flowers are in axillary or subterminal cymes.
• Flowers are aromatic and consist of 5-7 sepal and petals.
• The pedicles are about 5-15 mm long.
• Ovary 3-5 carpellate and each carple have 4-6 ovulate.
• Capsules are depressed- globose, brownish, lobate and 2 cm broad.
• Capsules are having 1-3 sub- globose seeds in each lobe.

5. 3. Chemical constituents:
• The leaves of tea consist of thease which is an enzymatic mixture containing
an oxidase, which partly converts the phlobatannin into phlobaphene, as
chemical constituent.
• Other chemical constituent present in tea leaves are tannins, caffeine.
• It contain 1-5% of tannin and 10-24% of caffeine.
• In tea leaves theobromine is also present in small amount.
• Tea leaves also consist of theophylline and volatile oil.
• Alkaloid content also present in tea leaves but its amount only depend on
season and age of tea leaves.
• Seeds of C. sinensis contain acylated oleane type triterpenes having
antiallergic activities.
•

6. Major chemical constituents are catechins and theoflavins.
• Physically, tea has both qualities of solution and suspension.
• Caffeine is about 3% of tea’s dry weight.
• Black tea contain dietary mineral manganese about 0.5 miligrams.
• Fluoride is also present in tea in small amount.
• Polyphenols are most abundant chemical constituents present in tea.(30-
40%)
• Example of polyphenols present in tea leaves are flavonoids ,
epigallocatechin gallate and other catechins

7. Uses:
• Drinking black or green tea have beneficial effects on body.
• It is non-alcoholic beverages.
• It has strong antioxidant property due to presence of caffeine in addition with
polyphenols.
• It also have free radical scavenging properties.
• It helps in the inhibition of angiogenesis i.e. the process involving the growth of
blood vessel essential for tumour growth and metastasis.
• It is used to treat genetic haemochromatosis via inhibition of absorption of iron
by tannates and other ligands.

8. • It helps to treat blindness caused due to diabetes which is an angiogenic condition.
• It helps to lower the risk of ischemic heart disease in older man.
• The major application of tea is to maintain cardiovascular health.
• It helps in the prevention of cancer.
• Green and black tea helps to protect against obesity .
• It also helps to treat alzheimer’s disease.

9. 5. Adulterants:
The common adulterants of soapstone, gypsum, graphite, indigo dye and
Prussian blue dye substances.