J Xu and J Liu are responsible for the study's design, funding acquisition, progress monitoring, technical guidance provision, manuscript compilation and editing, as well as final revision. Z Zhu is responsible for providing technical guidance. Z Hu is responsible for design of new compounds, chemical synthesis and structural elucidation of most of the new compounds, as well as conducting molecular modeling studies, a part of the monoamine oxidase B and acetylcholinesterase assay and writing original draft. S Zhou conducted in vitro biological investigations and in vivo cognitive impairment experiments. J Li, X Li and Y Zhou conducted a portion of the synthesis as well as performing the monoamine oxidase B and acetylcholinesterase assay.