Tacrine-based Multifunctional Agents in Alzheimer's Disease: An Old Story in Continuous Development§.

BACKGROUND: The design of multifunctional agents represents one of the most active research field in medicinal chemistry. In particular, tacrine, a well known Acetylcholinesterase inhibitor, is one of the most used starting point to develop multifunctional ligands and hundreds of papers report about these new agents. This is the third review of a series concerning tacrinebased multifunctional ligands; in particular, in the present, we will summarize and discuss the most intriguing examples of tacrine-based multifunctional agents published since 2013 until 2016. METHODS: We analyzed the bibliographic databases for peer-reviewed publications concerning tacrine-based multifunctional agents possessing biological actions that go beyond the simple "cholinergic" blockage. These papers have been subdivided according to their biological activities. Since this is the third review of a series, we took into considerations only the papers appeared since 2013 until 2016. RESULTS: In this review, we have analyzed more than 33 papers. All the reported compounds retain good inhibitory activity towards acetyl- and butyryl-cholinesterase. The other biological activities concern mostly inhibition of a) ß-amyloid aggregation, b) ß-secretase, c) monoamino oxidases, modulation of τ and ROS and metal chelation. CONCLUSION: The analysis of the current literature reported in this review confirm the importance of tacrine as scaffold to develop multifunctional agents potentially usefull to contrast Alzheimer's disease. Furthermore, the compounds herein reported showed very intriguing biological activities that could be used as starting point to develop new compounds even more interesting and, hopefully, clinically usefull to contrast Alzheimer's Disease.

Combined inhibition of the EGFR/AKT pathways by a novel conjugate of quinazoline with isothiocyanate.

Epidermal growth factor receptor inhibitors (EGFR-TKIs) represent a class of compounds widely used in anticancer therapy. An increasing number of studies reports on combination therapies in which the block of the EGFR-TK activity is associated with inhibition of its downstream pathways, as PI3K-Akt. Sulforaphane targets the PI3K-Akt pathway whose dysregulation is implicated in many functions of cancer cells. According to these considerations, a series of multitarget molecules have been designed by combining key structural features derived from an EGFR-TKI, PD168393, and the isothiocyanate sulforaphane. Among the obtained molecules 1-6, compound 6 emerges as a promising lead compound able to exert antiproliferative and proapoptotic effects in A431 epithelial cancer cell line by covalently binding to EGFR-TK, and reducing the phosphorylation of Akt without affecting the total Akt levels.

Isothiocyanate synthetic analogs: biological activities, structure-activity relationships and synthetic strategies.

Sulforaphane is a natural product that is constantly under biological investigation for its unique biological properties. This naturally occurring isothiocyanate (ITC) and its analogs are the main components of cruciferous vegetables, such as cauliflower, watercress, broccoli, cabbage, Brussels sprouts, widely used as chemopreventive agents. Due to their interesting biological profiles, natural ITCs have been exploited as starting point to develop new synthetic analogs. The present mini-review briefly highlights the most important biological actions of selected new synthetic ITCs focusing on their structure-activity relationships and related synthetic strategies.