ABSTRACT
Alkaloids are basic heterocyclic ring-containing compounds with an electronegative atom (usually nitrogen), having immense therapeutic potential for cognitive disorders. They are highly toxic in nature. The US Food and Drug Administration has registered the use of two plant-derived alkaloids, namely galantamine and rivastigmine, exhibiting acetylcholinesterase inhibitory activity, for symptom alleviation of Alzheimer’s disorder (AD). Moreover, clinical trials of four other alkaloids with similar modes of action, namely huperzine A, caffeine, nicotine, and indomethacin, have been carried out, although without convincing evidence for their clinical efficacy with respect to treatment of AD. Rhynchophylline, a plant-derived non-competitive N-methyl-D-aspartate (NMDA) antagonist, has been studied extensively for its neuroprotective activity. In-silico screening of rhynchophylline revealed its potential as an EphA4 inhibitor, a novel target for AD. In this chapter, we review the pathophysiological aspects of AD, current treatment protocols, and the potential useful activities of a few selected plant alkaloids, featuring their different targets and the key results from preclinical and clinical trials. Future research ought to develop progressively thorough clinical investigations into the most encouraging alkaloids, the further improvement of competitor alkaloids, and the nonstop quest for new alkaloids for important medication targets. An alkaloid sedative competitor could essentially influence the progress of AD, while also providing alleviation of symptoms.
