Drugs are the substances used to diagnosis, cure,
mitigation, treatment, or prevention of disease.These come from different
sources by utilizing several methods.These sources may be.
Natural
Semisynthetic
Synthetic
1.
NATURAL
Natural sources are plants,animal,micro-organisms.Most drugs
comes from these major sources.
o
PLANTS
Plants
have been used for centuries for treatment of disease. These were used in home
preparations.for exampleFor centuries, Willow Bark (Salix species) was used for
the treatment of arthritis, fever, various aches and pains. A lot of drugs
come from the plants.
Examples
are;
LEAVES; The leaves of Digitalis Purpurea are the
source of Digitoxin and Digoxin, which are cardiac glycosides.Leaves of
Eucalyptus give oil of Eucalyptus, which is important component of cough
syrup.Tobacco leaves give nicotine.Atropa belladonna gives atropine.
FLOWERS; Poppy papaver somniferum gives morphine (opoid).Vinca rosea
gives vincristine and vinblastine .Rose gives rose water used as tonic.
FRUITE; Senna pod gives anthracine, which is a
purgative (used in constipation).Calabar beans give physostigmine, which is
cholinomimetic agent.
Seeds:Seeds of Nux Vomica give strychnine, which is
a CNS stimulant.
Castor
oil seeds give castor oil.Calabar beans give Physostigmine, which is a
cholinomimetic drug.
Roots: Ipecacuanha root gives Emetine, used to induce vomiting as in
accidental poisoning. It also has amoebicidal properties.Rauwolfia serpentina
gives reserpine, a hypotensive agent.Reserpine was used for hypertension
treatmen.
Bark: Cinchona bark gives
quinine and quinidine, which are antimalarial drugs. Quinidine also has
antiarrythmic properties..Atropa belladonna gives atropine, which is
anticholinergic.Hyoscyamus Niger gives Hyosine, which is also anticholinergic.
B.ANIMAL SOURCE
Animal
provides a lot of substancs like milk,butter,meat,minerals etc which are
essentials for maintenance of healthy life.The trend to keep the animals for
these substances in homes and farms,was very ancient since the origine of human
life,But emergence of science and resaerch techniques the old concept was
modified.Now a days a lot of life saving medicines are being btained from the
animals.Health care professionals are looking towards animals for cure of
disaeses.
Few
examples of Drugs obtained from animals are with new technologies.
- Pancreas is a source of Insulin, used in treatment of Diabetes.
- Urine of pregnant women gives human chorionic gonadotropin (hCG) used for the treatment of infertility.
- Sheep thyroid is a source of thyroxin, used in hypertension.
- Cod liver is used as a source of vitamin A and D.
- Anterior pituitary is a source of pituitary gonadotropins, used in treatment of infertility.
- Blood of animals is used in preparation of vaccines.
- Stomach tissue contains pepsin and trypsin, which are digestive juices used in treatment of peptic diseases in the past. Nowadays better drugs have replaced them.
3.Microorganisms
·
Microbial
metabolites used as drugs, especially the antibiotics and antineoplastic agents
are produced by fermentation.
·
a strain of mold Penicillium chrysogenicum
produces Penicillin G
·
Clavulanic
acid is a product of
fungus Streptomyces clavuligerus
·
Microorganism
from sea water, identified as Cefalosporium acremonium, gives material for the
production of semisynthetic cephalosporins
·
Streptomycine
was isolated from a strain of Streptomyces griseus
·
Gentamicin
is produced by Micromonospora purpurea, an actinomycete
4.Minerals
·
Precipitated sulfur is a very fine powder for external use,
acting as parasiticide, which is used in the treatment of skin disorders
·
Purified sulfur is used internally only, as a laxative.Talc
powder is an absorben etc.
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