Synthesis, antioxidant properties and neuroprotection of α-phenyl- tert -butylnitrone derived HomoBisNitrones in in vitro and in vivo ischemia models

We herein report the synthesis, antioxidant power and neuroprotective properties of nine homo-bis-nitrones HBNs 1 – 9 as alpha-phenyl- N - tert -butylnitrone ( PBN ) analogues for stroke therapy. In vitro neuroprotection studies of HBNs 1 – 9 against Oligomycin A/Rotenone and in an oxygen-glucose-deprivation model of ischemia in human neuroblastoma cell cultures, indicate that (1 Z ,1′ Z )-1,1′-(1,3-phenylene)bis( N -benzylmethanimine oxide) ( HBN6 ) is a potent neuroprotective agent that prevents the decrease in neuronal metabolic activity (EC 50 = 1.24 ± 0.39 μM) as well as necrotic and apoptotic cell death. HBN6 shows strong hydroxyl radical scavenger power (81%), and capacity to decrease superoxide production in human neuroblastoma cell cultures (maximal activity = 95.8 ± 3.6%), values significantly superior to the neuroprotective and antioxidant properties of the parent PBN . The higher neuroprotective ability of HBN6 has been rationalized by means of Density Functional Theory calculations. Calculated physicochemical and ADME properties confirmed HBN6 as a hit-agent showing suitable drug-like properties. Finally, the contribution of HBN6 to brain damage prevention was confirmed in a permanent MCAO setting by assessing infarct volume outcome 48 h after stroke in drug administered experimental animals, which provides evidence of a significant reduction of the brain lesion size and strongly suggests that HBN6 is a potential neuroprotective agent against stroke.