Synthesis and biological evaluation of novel 8- substituted sampangine derivatives as potent inhibitor of Zn2+-Aß complex mediated toxicity, oxidative stress and inflammation.

A series of 8-substituted sampangine derivatives have been designed, synthesized and tested for their ability to inhibit cholinesterase and penetrate the blood-brain barrier. Their chelating ability toward Zn2+ and other biologically relevant metal ions was also demonstrated by isothermal titration calorimetry. The new derivatives exhibited high acetylcholinesterase inhibitory activity, high blood-brain barrier penetration ability and high chelating selectivity for Zn2+. Moreover, compound 10 with the strongest binding affinity to Zn2+ was selected for further research. Western blotting analysis, transmission electron microscopy, DCFH-DA assay and paralysis experiment indicated that compound 10 suppressed the formation of Zn2+-Aß complexes, alleviated the Zn2+ induced neurotoxicity and inhibited the production of ROS catalyzed by Zn2+ in Aß42 transgenic C. elegans. Furthermore, compound 10 also inhibited the expressions of pro-inflammatory cytokines, such as NO, TNF-α, IL-6 and IL-1ß, induced by Zn2+ + Aß1-42 in BV2 microglial cells. In general, this work provided new insights into the design and development of potent metal-chelating agents for Alzheimer's disease treatment.

Novel sampangine derivatives as potent inhibitors of Cu2+-mediated amyloid-ß protein aggregation, oxidative stress and inflammation.

A series of 11-substituted sampangine derivatives have been designed, synthesized, and tested for their ability to inhibit cholinesterase. Their chelating ability and selectivity for Cu2+ over other biologically relevant metal ions were demonstrated by isothermal titration calorimetry. Their blood-brain barrier permeability was also tested by parallel artificial membrane permeation assay. Among the synthesized derivatives, compound 11 with the strong anti-acetylcholinesterase activity, high blood-brain barrier penetration ability and high binding affinity to Cu2+ was selected for further research. Western blotting analysis, transmission electron microscopy, DCFH-DA assay and paralysis experiment indicated that compound 11 suppressed the formation of Cu2+-Aß complexes, alleviated the Cu2+ induced neurotoxicity and inhibited the production of ROS catalyzed by Cu2+ in Aß42 transgenic C. elegans. Moreover, compound 11 also inhibited the expressions of proinflammatory cytokines, such as NO, TNF-α, IL-6 and IL-1ß, induced by Cu2+ + Aß1-42 in BV2 microglial cells. In general, this work provided new insights into the design and development of potent metal-chelating agents for AD treatment.

Electrochemical Synthesis of 1-Naphthols by Intermolecular Annulation of Alkynes with 1,3-Dicarbonyl Compounds.

C-centered radical cyclization under electrochemical conditions is a feasible strategy for constructing cyclic structures. Reported herein is the electrochemical synthesis of highly functionalized 1-naphthols using alkynes and 1,3-dicarbonyl compounds by (4 + 2) annulation of C-centered radical. Electrolysis was conducted with Cp2Fe as redox catalyst, thereby eliminating the use of oxidants and transition-metal catalysts. The synthesized 1-naphthol compounds showed good antitumor activity in vitro, and further studies indicated that compound 3bl induced tumor cell apoptosis.