The Research About Antidepressant Effects Of Butanol Extracts From Stevia And Its Mechanism

BackgroundStevia is asteraceae perennial herbaceous plants,traditionally,it was considered to act as thirst quenching,promoting digestion,nourishing the liver and raising its efficacy,and keeping mild on refreshing and qingrejiedu,and other effects.Our preliminary study found that stevia leaf extract has obvious antidepressant effect.To understand the further antidepressant effect and mechanism of stevia,the leaf were respectively extracted by the petroleum ether,ethyl acetate,n-butyl alcohol and water.Preliminary experiments found that the antidepressant effect of n-butyl alcohol extract(Butanol Extract from Stevia,BEFS)was the best.ObjectiveOn prior basis,this study further explore different doses of BEFS for antidepressant effect and mechanism.MethodsTo establish chronic unpredictable mild stress(CUMS)depression model mice,using different doses of BEFS(3 g/kg and 6 g/kg)for intragastric administration,once a day at 14:00,for two weeks.Based on body weight in mice,sport activity(open flied test)and sucrose preference to assess different doses of BEFS antidepressant effect.Using transmission electron microscopy observing hippocampus and the prefrontal cortex neuron damage and apoptosis morphology in mice to assess BEFS central neuron protecting effect.q RT-PCR and Western blot were respectively detected the expression levels of NF-κB,SIGIRR,and IL1rl1 genes and protein in the hippocampus and prefrontal cortex.ResultsThe results showed that the body weight in mice,horizontal mobile score,numbers of upright and sucrose preference were significantly decreased in the CUMS(P(27)0.05 or P(27)0.01).Behavior of depression model mice were significantly improved by BEFS(P(27)0.05 or P(27)0.01).Electron microscopy(sem)results showed that the BEFS could significantly inhibit the neuronic apoptosis in hippocampus and prefrontal cortex.The q RT-PCR and Western bolt results showed that SIGIRR gene and its protein expression were increased,and the IL1rl1 and NF-κB level were declined in the hippocampus and prefrontal cortex with in a dose-dependent manner(P(27)0.05 or P(27)0.01).ConclusionsThe results of the present study show that BEFS significantly improved depressive symptoms in mice in a dose-dependent manner,and the mechanism may be associated with changes in SIGIRR,IL1rl1 and NF-κB expression levels.