Purine Alkaloids
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Purine contains double carbon ring containing four nitrogen atoms. Purine alkaloids have a molecular structure remarkably similar to the nitrogenous purine base adenine, which is found in DNA, RNA and ATP. Iriosine and xanthosine monophospate, (IMP and XMP) are two important precursors derived via the primary purine biosynthetic pathway.
PURINE ALKALOIDS
Purine contains double carbon ring containing four nitrogen
atoms. Purine alkaloids have a molecular structure remarkably similar to the
nitrogenous purine base adenine, which is found in DNA, RNA and ATP. Iriosine
and xanthosine monophospate, (IMP and XMP) are two important precur-sors
derived via the primary purine biosynthetic pathway. They have a CNS; stimulant
effect, relax bronchial smooth muscles and have a diuretic effect. Mode of
action is via inhibition of phosphodiesterase, this increases production of
cAMP causing release of adrenaline. These alkaloids are derived from adenine
and guanine which are the purine base components of the nucleotides adenosine
and guanos-ine. The nucleotides adenosine and guanosine are derived from IMP
and XMP respectively. The purine alkaloids are derived from XMP.
Most notable of the purine alkaloids are the mild stimulants
caffeine and the very similar theobromine. Caffeine occurs naturally in many
beverage plants, including coffee (Coffea
arabica) belonging to the family Rubiaceae, tea (Thea sinensis) belonging
to the tea family (Theaceae), yerba mate (Ilex paraguariensis) in the holly family
(Aquifoliaceae) and cola (Cola nitida)
in the chocolate family (Sterculiaceae). The primary source of theobromine is
from the seeds of Cacao (Theobroma cacao), another member of the chocolate family
(Sterculiaceae).
