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Africa
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Multi-Functional Monoamine Oxidase and Cholinesterase Inhibitors for the Treatment of Alzheimer’s Disease
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Ireen Denya, Sarel F. Malan, Jacques Joubert
Resveratrol, a natural product with a stilbene structure, has been widely studied for its wide range of biological activities. Recent research has suggested that resveratrol is an anti-AD agent which possesses antioxidant, anti-inflammatory, MAO inhibitory and neuroprotective properties (Baur and Sinclair, 2006; Lu et al., 2013b). Moreover, pyridoxine (vitamin B6) has been shown to be a potent antioxidant that may have some benefit in AD models (Yang et al., 2017). Mannich base derivatives (another good antioxidant) were introduced to the pyridoxine-resveratrol hybrids (Fig. 11.26) and evaluated for ChE, MAO and antioxidant activity. The results confirmed what other studies have described and established SARs such as the necessity of a pyrollidine or piperidine moiety for AChE activity. Introduction of the Mannich base to the hybrids, however, decreases both ChE and MAO activity. Overall the compounds displayed poor inhibitory profiles, but these preliminary findings could serve as a starting point for the design of new MTDLs (Yang et al., 2017).
Treatment and prevention of malaria
Published in David A Warrell, Herbert M Gilles, Essential Malariology, 2017
David A Warrell, William M Watkins, Peter A Winstanley
Pyronaridine is an azacrine-type Mannich base with structural similarities to both mepacrine and amodiaquine. Effects on haemoglobin degradation, haem polymerization and topoisomerase-2 activity have been suggested, but the precise mode of action remains unknown. There are conflicting reports on cross-resistance between chloroquine and pyronaridine: studies in China and on isolates from Africa show no correlation, in contrast to studies on isolates from Thailand and Somalia (Elueze et al., 1996). For parasites from a range of geographical locations, there is a positive correlation between chloroquine and pyronaridine chemosensitivity in vitro at the IC50 (50% inhibitory concentration), but not the IC90 (90% inhibitory concentration) level.
Pyronaridine–Artesunate
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Pyronaridine (C29H32ClN6O2; 4-[{7-chloro-2-methoxy-pyrido (3,2-b)quinolin-10-yl}amino]-2,6-bis[pyrrolidin-1-ylmethyl] phenol; molecular weight 518.05 g/mol) is a schizonticidal anti-malarial drug belonging to the benzonaphthyridine derivative class (also known as Mannich base derivatives) that has similar structural chemistry to the 4-aminoquinoline drugs (Figure 173.1) (Biagini et al., 2005). It therefore has physicochemical and pharmacokinetic properties and mechanism of action that are broadly similar to those of other aminoquinoline anti-malarials such as chloroquine, amodiaquine, piperaquine, and naphthoquine.
Application of the Mannich reaction in the structural modification of natural products
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Miao-Xia Pu, Hong-Yan Guo, Zhe-Shan Quan, Xiaoting Li, Qing-Kun Shen
The Mannich reaction, also known as the amine methylation reaction, is an organic chemical reaction in which a compound (typically a carbonyl compound) containing reactive hydrogen is condensed with formaldehyde and secondary amine or ammonia to form α，β-amino (carbonyl) compound. It is also an important reaction type and a key reaction step in the synthesis of numerous drugs and natural products. The Mannich reaction mechanism is as follows (Figure 1). The product of the reaction β-amino (carbonyl) compound is referred to as the Mannich base. It contains nitrogen atoms, which can increase the water solubility of the compound, increase its affinity for the receptor, and increase the bioavailability and pharmacological activity of the drug molecule. Investigation of the literature has shown that Mannich bases have a wide range of biological characteristics, including anti-cancer2, anti-inflammatory3, analgesic4, and antimicrobial activities5. In this paper, we review the progress of the Mannich reaction for the modification of natural products according to the classification of their biological activities.
Recent developments concerning the application of the Mannich reaction for drug design
Published in Expert Opinion on Drug Discovery, 2018
Bernhard Biersack, Khursheed Ahmed, Subhash Padhye, Rainer Schobert
The Mannich reaction is a pivotal one-pot procedure widely applied for the aminoalkylation of phenols, electron-rich heterocycles, and enolizable ketones to give the corresponding Mannich bases. These are characterized by their polarity, compatibility with aqueous media, and the many ways of their further functionalization.