Medicinal plants and their therapeutically active secondary metabolites have
been functioning as prolific remedial resource from ancient times and among diverse
range of chemical entities of ethno-medico-botanicals, bioactive potential of alkaloids
are immense. The alkaloids, reported approximately from 20% of plant species,
represent a diverse group of low molecular weight nitrogen-containing heterocyclic
natural products, derived mostly from amino acids via transamination. In-depth
experimental understanding of the metabolic regulation of the key metabolites is
cynosure of modern herbal drug research. In this review we have streamlined both
traditional and experimental knowledge elucidating utility aspects of plant based
alkaloids as a curative tool to alleviate cardiovascular disorder which is the major cause
of mortality and morbidity throughout the globe. Cardio-protection through plants and
plant based formulations are reported in traditional medicines of many countries and
present day research has demonstrated the role of alkaloids as anti-hypertensive,
hypno-analgesic, anti-angiogenic, anti-ischemic, anti-depressant and vesorelaxant which
have possibly attributed to their cardioprotective efficacy. In some cases antioxidative,
antihypercholesteroemic, inhibition of platelet aggregation and anti-inflammatory
activities of alkaloids have also reduced the risk of cardiovascular disorders. The
cardioprotective drugs of plant origin in present day medical practice includes several
alkaloids like tetrandrine and fangchinoline from members of genus Stephania;
berberine from S. japonica and S. cepharantha; dauricine and daurisoline from
Menispermum duricum; rhynchophylline and hirsutine from Uncaria rhynchophylla,
reserpine, ajmaline, ajmalicine, yohimbine, serpentine from Ravolfia serpentina;
dehydroevodiamine from Evodiae rutaecarpa, α-tomatine, and tomatidine from
tomatoes etc. These alkaloids exhibit a wide array of mechanisms including in vivo
vasodilation by lowering blood pressure or prolonging A-H and H-V intervals to widen
ventricular action potentials. Among other significant mechanisms, there is alteration
of calcium influx in response to activation of the voltage sensitive channels or negative inotropic actions, preferably due to interaction with sodium channels. Therefore, the
present review is the summarized database of plant alkaloids investigated exclusively
as a resource of cardio-protective therapeutics in both in vitro and in vivo models with
the possible underlying mechanism of action with a note on their ethnopharmacological
relevance and a glimpse on their structure activity relationship studies.
Keywords: Alkaloids, Cardioprotective, Ethnopharmacology, Medicinal plants,
Structure activity.
