The multifactorial nature of Alzheimer’s disease (AD) is a reason for the lack of effective drugs as well as a basis for the development of “multi-target-directed ligands” (MTDLs). As cases increase in developing countries, there is a need of new drugs that are not only effective but also accessible. With this motivation, we report the first sustainable MTDLs, derived from cashew nutshell liquid (CNSL), an inexpensive food waste with anti-inflammatory properties. We applied a framework combination of functionalized CNSL components and well-established acetylcholinesterase (AChE)/butyrylcholinesterase (BChE) tacrine templates. MTDLs were selected based on hepatic, neuronal, and microglial cell toxicity. Enzymatic studies disclosed potent and selective AChE/BChE inhibitors (5, 6, and 12), with subnanomolar activities. The X-ray crystal structure of 5 complexed with BChE allowed rationalizing the observed activity (0.0352 nM). Investigation in BV-2 microglial cells revealed antineuroinflammatory and neuroprotective activities for 5 and 6 (already at 0.01 μM), confirming the design rationale.

Alzheimer´s disease (AD) is a progressive neurodegenerative dementia which currently represents one of the biggest threats for the human kind. The cure is still unknown and various hypotheses (cholinergic, amyloidal, oxidative, vascular etc.) are investigated in order to understand the pathophysiology of the disease and on this basis find an effective treatment. Tacrine, the first approved drug for the AD disease treatment, has been reported to be a multitargeted drug, however it was withdrawn from the market particularly due to its hepatotoxicity. Its derivative 7-methoxytacrine (7- MEOTA) probably due to the different metabolization does not exert this side effect. The aim of our study was to compare these two cholinesterase inhibitors from various, mainly cholinergic, points of view relevant for a potential AD drug. We found that 7-MEOTA does not fall behind its more well-known parent compound – tacrine. Furthermore, we found, that 7-MEOTA exerts better properties in most of the tests related to a possible AD treatment. Only the pharmacokinetics and a higher acetylcholinesterase and butyrylcholinesterase inhibitory potency would slightly give advantages to tacrine over 7-MEOTA, but concerning its lower toxicity, better antioxidant properties, interaction with muscarinic and nicotinic receptors and “safer” metabolization provide strong evidence for reconsider 7-MEOTA and its derivatives as candidate molecules for the treatment of AD.