Effect of acute treatment of test compounds on immobility in the forced-swim test in ICR mice: (A) compound 14 (10 mg/kg, 37 µmol/kg and 30 mg/kg, 112 µmol/kg); (B) compound 19 (0.3 mg/kg, 1.0 µmol/kg and 3 mg/kg, 10 µµmol/kg) and (C) compound 21 (0.3 mg/kg, 0.5 µmol/kg and 3 mg/kg, 5 µmol/kg). Vehicle (Veh) or test agent was injected i.p. 30 min prior to the test. n = 9–11; * P < 0.05 vs. Veh.