8. Lactone and isothiocyanate Glycosides Flashcards
What are coumarin glycosides?
Coumarin glycosides arevery fragrant: they are the source, for instance, of freshly-mown hay scents.
What are the uses of coumarin glycosides?
Medicinally, coumarin glycosides have been shown to have hemorrhagic, antifungicidal, and antitumor activities. The lactone glycoside dicumarol is known as an anticoagulant.
Which natural products contain lactone?
Other lactone containing natural products include canthandin and methoxsalen which are used for dermatologic purposes, and santonin, was formerly used as an anthelmintic, but its use has been discontinued.
What are cantharides?
Cantharides, Spanish flies, Russian flies, or blistering flies consists of the dried insect, Cantharis vesicatoria
Where are cantharides found?
This insect is found on certain shrubs of the Caprifoliaceae and Oleaceae that grow in southern and central Europe.
When do mature insects appear?
Mature insects, which are brilliant green with a metallic luster, usually appear in June or July.
How are cantharides collected?
.In the early morning, when the insects are still sluggish from the cold night air, the shrubs are shaken or beaten with poles.
The insects are collected on cloths spread on the ground.
They are killed by plunging them into dilute vinegar, by exposure to the fumes of hot vinegar, ammonia, or sulfur dioxide, or by means of chloroform, ether, or similar drugs.
After the insects are killed, they are carefully dried at a temperature not higher than 40°C.
How are cantharides stored?
Drug should be stored in tight containers, and a few drops of chloroform or carbon tetrachloride should be added occasionally to preserve the drug from attack by other insects.
What are the constituents of cantharides?
Cantharides contains as its chief constituent the vesicating principle, cantharidin (0.6 to 1.0%), which is lactone or anhydride of cantharidic acid. In addition about 12% of a fat is associated with the cantharidin in the soft body tissues of the insect.
What are uses of cantharides?
Cantharides is an irritant, a vesicant, and rubefacient.
Topical application of a solution of cantharidin is effective in the removal of certain types of warts; preparations containing 0.7% cantharidin are available for this purpose.
What are the adverse effects of cantharides?
If taken internally, it is excreted by the kidney, irritates the urinary tract, and can result in priapism.
This accounts for the drug’s popular reputation as an aphrodisiac.
Internal administration of cantharides is potentially dangerous, however, and deaths have been reported.
Which plants contain isothicyanate glycosides?
Seeds of several cruciferous plants contain glycosides, the aglycones of which are isothiocyanates.
These aglycones may be either aliphatic or aromatic derivatives/
What are the principal isothiocyanate glycosides found in nature?
Principal among these glycosides are sinigrin from black mustard, sinalbin from white mustard, and gluconapin from rape seed.
What happens when the glycosides are hydrolyzed?
When hydrolyzed by the enzyme myrosin, they yield the mustard oils.
What is black mustard?
Black mustard, sinapis nigra, or brown mustard is the dried ripe seed of varieties of Brasica nigra or of B. juncea or of varieties of these species (Fam. Cruciferae).
