Properties
| Home | | Pharmacognosy |Chapter: Pharmacognosy and Phytochemistry : Drugs Containing Alkaloids
Although numerous alkaloids exist, they have similar prop-erties when separated. In general, they are colourless, crystalline solids which are basic, have a ring structure, and have definite melting points. They are also derived from plants and have a bitter taste. However, some exceptions are known. For instance, some alkaloids are not basic..........
PROPERTIES
Although numerous alkaloids exist, they have similar
prop-erties when separated. In general, they are colourless, crystalline solids
which are basic, have a ring structure, and have definite melting points. They
are also derived from plants and have a bitter taste. However, some exceptions
are known. For instance, some alkaloids are not basic and others are brightly
coloured (betanidine, beriberine, sangui-narine) or liquid (nicotine). Other
alkaloids are produced synthetically. Most alkaloids are also chiral molecules
which mean they have nonsuperimposable mirror images. This results in isomers
that have different chemical properties. For example, one isomer may have a
physiological function while the other does not.
Generally free bases of alkaloids are soluble in organic
solvents and insoluble in water, where as alkaloidal salts are soluble in water
and partially soluble in organic solvents. For example, strychnine
hydrochloride is much more soluble in water than strychnine as a base.
