Chromatographic separations were performed on silica gel columns (Kieselgel 40, 0.040C0.063 mm; Merck, Darmstadt, Germany) by flash chromatography. neuronal toxicity. The therapeutic approach should therefore try to decrease amyloid production (Citron 2002; Guo and Hobbs 2006; Hills and Vacca 2007), or block accumulation of misfolded peptide aggregates (Talaga 2001; Estrada and Soto 2007). Among the mechanisms involved in Agenerates various reactive oxygen species (ROS), such as hydrogen peroxide, hydroxyl radical, and superoxide anion by directly interacting with metals or indirectly by impairment of mitochondrial activity (Bobba et al. 2010). In addition, the overload of ROS induces accumulation of Aestablishing a vicious circle that reinforces the oxidative stress with strengthening of oxidative damage at neuronal level (Tamagno et al. 2008). Among the mechanisms involved in neuronal dysfunction and death, the accumulation of Apeptide, in different aggregation forms, including soluble oligomers and insoluble fibrils, has also been linked to inflammation responses in AD (Glass et al. 2010). It is recognized that the microglial cells enhance and amplify neuronal damage induced by Ahas been shown to activate microglial cells, in part by signaling through toll-like receptors and Melanocyte stimulating hormone release inhibiting factor glycosylation end products, which in turn induce the production of factors such as nitric oxide (NO), ROS, proinflammatory cytokines, chemokines and prostaglandins that promote neuronal death (Glass et al. 2010). Due to the complexity of this disease and the involvement of different proteins in its progression, the modulation of a single factor might not be sufficient to produce the desired efficacy. Indeed, the current management of AD is being reviewed and researchers are now turning to the design of structures that could be able to simultaneously interact with different targets involved in the pathogenic process. Our research group has been involved for several years in the development of potential drugs for AD. In particular, AP2238 was the first dual binding site human acetylcholinesterase (hAChE) inhibitor (Piazzi et al. 2003) for which the simultaneous inhibition of the catalytic activity and the proaggregatory action of AChE on amyloid-peptides was verified. Extensive structureCactivity relationship studies (Piazzi et al. 2007) have shown that the structure of AP2238 is crucial for optimal activity. Indeed, only the introduction of an ethyl group (AP2243) instead of a methyl Melanocyte stimulating hormone release inhibiting factor group on the basic nitrogen led to an improvement in the anti-AChE activity without decreasing the Melanocyte stimulating hormone release inhibiting factor inhibitory potency on the AChE-induced Aaggregation. In this article we describe a simple structural modification of AP2243 (Fig. ?(Fig.1),1), leading to the introduction of the catechol moiety. This structural modification was based on the observation that catechol itself and catechol derivatives such as Melanocyte stimulating hormone release inhibiting factor dopamine and quercetin were recently shown to possess antiaggregating properties (Di Giovanni et al. 2010; Huong et al. 2010). In addition, quercetin was also shown Melanocyte stimulating hormone release inhibiting factor to inhibit Rabbit Polyclonal to GFP tag BACE1 in both a cell-free system and in neuronal cells (Shimmyo et al. 2008). Finally, it is also well-known that catechols have antioxidant activity, which might be beneficial in the treatment of AD patients (Amorati and Valgimigli 2012; Valgimigli and Pratt 2012). Therefore, the simple switch from the 6,7-methoxy-2H-2-chromenone nucleus of AP2238 and AP2243 to a catecholic one is expected to enlarge the neuroprotective profile of the resulting compound and obtain an effective multi-target directed ligand. In this regard, we evaluated the neuroprotective profile of AP2238 and AP2243 in terms of anticholinesterase and antiaggregating activities, BACE1 inhibition, together with antioxidant, neuroprotective, anti-inflammatory activity at neuronal and microglial cell level. Open in a separate window Figure 1 Drug design and synthesis of AP2469. Materials and Methods Chemistry General methods Melting points were measured in glass capillary tubes on a Bchi SMP-20 apparatus (Milan, Italy) and are uncorrected. Direct infusion ES-MS spectra were recorded on a Waters Micromass ZQ 4000 apparatus (Milan, Italy). 1H NMR experiments were recorded on Varian VXR 300 MHz instruments (Palo Alto, CA). Chemical shifts are reported in parts per million (ppm) relative to tetramethylsilane, and spin multiplicities are given as s (singlet), d (doublet), t (triplet), dd (double doublet), dt (double triplet), m (multiplet) or br (broad). The results of the elemental analysis are within 0.4% of the theoretical values. Chromatographic separations were performed on silica gel columns (Kieselgel 40, 0.040C0.063 mm; Merck, Darmstadt, Germany) by flash chromatography. Compounds.