Effect of Jobelyn® on intruder- and isolation-induced aggressive behavior in mice

Abstract

Aggression is a violent behavior emitted against another organism that may lead to its harm or death and thus is of public health significance, which necessitates the search for agents with anti-aggressive property. This study investigated the effect of Jobelyn® (JB), a unique African polyherbal formulation, on intruder- and isolation-induced aggressive behaviors in mice. Male mice that showed aggression after being housed individually with female counterparts for 3 weeks or kept in isolation for 4 weeks were treated orally (p.o.) with JB (5, 10 or 50 mg/kg), haloperidol (HP) (1 mg/kg), fluoxetine (FL) (10 mg/kg), p-chlorophenylalanine (PCPA) (20 mg/kg), mianserin (MS) (50 mg/kg) or distilled water (10 mL/kg) 60 min before being tested for aggression. Interaction studies involving oral administration of PCPA (20 mg/kg), FL (10 mg/kg) or MS (50 mg/kg) to aggressive mice that had received JB (5 or 10 mg/kg, p.o.) 30 min earlier were assessed. The effect of JB (5, 10 or 50 mg/kg, p.o.) on defensive behaviors was also evaluated. JB (5, 10 or 50 mg/kg) decreased aggressive behaviors without impairing the defensive mechanisms of mice. PCPA (20 mg/kg), an inhibitor of 5-hydroxytryptamine (5-HT) biosynthesis, increased aggressive responses and reduced the anti-aggressive effect of JB. FL (10 mg/kg), a 5-HT reuptake inhibitor, significantly suppressed aggression but did not alter the effect of JB on aggression. MS (50 mg/kg), a 5-HT receptor antagonist, reduced aggression and enhanced the effect of JB on aggression. These findings suggest that JB has anti-aggressive activity, which may be related to the enhancement of serotonergic system.