Fig. 1: Norisoboldine demonstrated an antidepressant efficacy in depression-like animal behaviors.

A1 The chemical structure of Norisoboldine (NOR). A2 Schematic timeline of the experimental procedures. A3 After the i.p. injection (5 mg/kg NOR and 10.0 mg/kg NOR) for sixty minutes, NOR significantly reduced the immobility time compared with the C57 mice in the tail suspension test (TST) (N = 9–10 per group). A4 After 5 days of injection, NOR significantly decreased the immobility time in the FST compared with the C57 mice (N = 9–10 per group). B1 Schematic timeline of the experimental procedures. B2 After CSDS procedure, sucrose preference index were determined to select the depression model mice (N = 6–14 per group). B3 After 60 minutes of NOR treatment, NOR significantly reduced the immobility time in the TST compared with the untreated CSDS mice (N = 7–14 per group). B4 After 4 days of NOR treatment, NOR significantly enhanced the sucrose preference index in the SPT compared with the untreated CSDS mice (N = 4–6 per group). B5 After 5 days of NOR treatment, NOR significantly reduced the immobility time in the FST compared with the untreated CSDS mice (N = 7–18 per group). Data were analyzed by one-way ANOVA followed by post hoc Tukey’s test and are presented as the mean ± SEM (*p < 0.05, **p < 0.01, ***p < 0.001).