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Alkaloids
Naturally
occurring, nitrogen-containing compounds that are alkaline in solution. They
usually have a bitter taste and are characterised by powerful physiological
activity. Examples are nicotine and caffeine.
Antioxidant
A compound which
retards oxidation.
Caffeine
An alkaloid found
in tea and coffee which acts as a nerve stimulant and diuretic.
Catechins
A group of related
polyphenolic compounds which occur in plants and are darkened by the action of
certain plant enzymes and oxygen an example of browning of cut fruit and
vegetables. Catechins can function as antioxidants.
Cardiovascular
concerning the heart and blood vessels.
Carcinogen
Any substance
or agent that can produce a cancer.
Diuretic
An agent that
promotes increased excretion of urine.
Electrophilic ultimate
carcinogens
Substances which directly cause cancer by reacting
with genetic material (DNA) and related cell components. (Many carcinogens,
designated pro-carcinogens (q.v.), require conversion to the ultimate
carcinogen by reactions taking place in the cells of the organism)
Epigallocatechin Gallate (EGCG, ECG, EGC,
EC)
A family of substances related to the simple catechins which
occur in green tea and which undergo browning reactions during processing to
black tea.
Free radical
A
highly reactive substance which, in some circumstances can lead to undesirable
chemical changes in the body through oxidisation, e.g. hardening of the blood
vessels and development of cancer.
Flavanoids, flavanols, flavonol
glycosides, flavandiols
Groups of related, naturally occurring
chemicals in plants. A number of substances in these classes have anti-oxidant
properties and many protect against deleterious changes brought about by
free-radicals in the body.
Gallic acid
A plant
polyphenolic which possess antioxidant properties.
Lipid
A member of the family
of fats which occur in living tissues either structurally or for nutritional
purposes.
Nicotinic acid
A water
soluble vitamin B complex.
Oxygen
symbol O. A
colourless, odourless gas constituting one-fifth of the atmosphere.
Oxidation
Changes which
are brought about by oxygen.
Polyphenols
Compounds
which contain several `phenol' groups and have antioxidant properties.
Polyphenolic components
Chemicals found in plants which have several groups containing
an oxygen and a hydrogen atom (called a phenol group).
Procarcinogen
A
substance capable of causing cancer but only when metabolised to a more
reactive compound.
Riboflavin
Vitamin
B2
Theaflavins
Yellow
coloured polyphenols occurring in black tea.
Thearubigins
Red/brown
pigments produced in black tea.
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