Advances on the Bioactivities, Total Synthesis, Structural Modification, and Structure-Activity Relationship of Cytisine Derivatives

: Cytisine is a quinolizidine alkaloid isolated from various Leguminosae plants. Cytisine and its derivatives exhibit a broad range of biological properties, such as smoking cessation aid, antidepressant, neuroprotective, nootropic, anticancer, antiviral, antiparasitic, antidiabetic, insecticidal, and nematicidal activities. In this review, the progress of cytisine and its derivatives in regard to bioactivities, total synthesis, structural modifications focusing on their N-12 position and lactam ring is reported. Additionally, structure-activity relationships of cytisine and its derivatives are also discussed.