Data on alkaloid interactions with the physiologically important transition metals, iron and copper, are mostly lacking in the literature. However, these interactions can have important consequences in the treatment of both Alzheimer's disease and cancer. As isoquinoline alkaloids include galanthamine, an approved drug for Alzheimer's disease, as well as some potentially useful compounds with cytostatic potential, 28 members from this category of alkaloids were selected for a complex screening of interactions with iron and copper at four pathophysiologically relevant pH and in non-buffered conditions (dimethyl sulfoxide) by spectrophotometric methods in vitro. With the exception of the salts, all the alkaloids were able to chelate ferrous and ferric ions in non-buffered conditions, but only five of them (galanthine, glaucine, corydine, corydaline and tetrahydropalmatine) evoked some significant chelation at pH 7.5 and only the first two were also active at pH 6.8. By contrast, none of the tested alkaloids chelated cuprous or cupric ions. All the alkaloids, with the exception of the protopines, significantly reduced the ferric and cupric ions, with stronger effects on the latter. These effects were mostly dependent on the number of free aromatic hydroxyls, but not other hydroxyl groups. The most potent reductant was boldine. As most of the alkaloids chelated and reduced the ferric ions, additional experimental studies are needed to elucidate the biological relevance of these results, as chelation is expected to block reactive oxygen species formation, while reduction could have the opposite effect.

• Keywords
• alkaloid, chelation, copper, iron, reduction,
• MeSH
• Alzheimer Disease * MeSH
• Chelating Agents chemistry   MeSH
• Cytostatic Agents * MeSH
• Dimethyl Sulfoxide MeSH
• Galantamine MeSH
• Hydroxyl Radical MeSH
• Isoquinolines pharmacology   MeSH
• Humans MeSH
• Copper chemistry   MeSH
• Reactive Oxygen Species MeSH
• Reducing Agents MeSH
• Salts MeSH
• Iron chemistry   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Chelating Agents MeSH
• Cytostatic Agents * MeSH
• Dimethyl Sulfoxide MeSH
• Galantamine MeSH
• Hydroxyl Radical MeSH
• Isoquinolines MeSH
• Copper MeSH
• Reactive Oxygen Species MeSH
• Reducing Agents MeSH
• Salts MeSH
• Iron MeSH

Alzheimer's disease (AD) is a progressive age-related neurodegenerative disease recognized as the most common form of dementia among elderly people. Due to the fact that the exact pathogenesis of AD still remains to be fully elucidated, the treatment is only symptomatic and available drugs are not able to modify AD progression. Considering the increase in life expectancy worldwide, AD rates are predicted to increase enormously, and thus the search for new AD drugs is urgently needed. Due to their complex nitrogen-containing structures, alkaloids are considered to be promising candidates for use in the treatment of AD. Since the introduction of galanthamine as an antidementia drug in 2001, Amaryllidaceae alkaloids (AAs) and further isoquinoline alkaloids (IAs) have been one of the most studied groups of alkaloids. In the last few years, several compounds of new structure types have been isolated and evaluated for their biological activity connected with AD. The present review aims to comprehensively summarize recent progress on AAs and IAs since 2010 up to June 2021 as potential drugs for the treatment of AD.

• Keywords
• Alzheimer’s disease, acetylcholinesterase, butyrylcholinesterase, docking study, isoquinoline alkaloids, monoaminooxidase, neuroprotective activity, prolyl oligopeptidase,
• MeSH
• Amaryllidaceae Alkaloids metabolism   MeSH
• Alzheimer Disease metabolism   MeSH
• Amaryllidaceae chemistry   MeSH
• Neurodegenerative Diseases metabolism   MeSH
• Prolyl Oligopeptidases metabolism   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Amaryllidaceae Alkaloids MeSH
• Prolyl Oligopeptidases MeSH