Alkaloid molecules can act, depending on a type of amine functionality present in alkalods, as either hydrogenacceptor
or hydrogen-donor for hydrogen bonding that is critically important for the interaction (binding) between targets
(enzymes, proteins and receptors) and drugs (ligands). Because of this unique property, alkaloid scaffolds are therefore
present in several drugs and lead compounds. This review highlights alkaloid scaffolds in drugs, particularly those recently
approved in 2012; it also covers the scaffolds in leads and drug candidates which are in clinical trials and preclinical
pipeline. The review focuses on three therapeutic areas including treatments of cancer, tuberculosis, and tobacco cessation.
Alkaloid scaffolds in drugs and leads are inspired by those of naturally occurring alkaloids, and these scaffolds include
pyridine, piperidine, quinoline, quinolinone, quinazoline, isoquinoline, indole, indolinone, isoindole, isoxazole, imidazole,
indazole, thiazole, pyrazole, oxazolidinone, oxadiazole, and benzazepine. In addition to medicinal chemistry aspects,
natural products possessing an individual alkaloid scaffold, as well as the mechanism of action of drugs and leads,
are also discussed in this review.