Keywords: Fructus Schisandrae Schisandra ttgnans extract Anxiety Restraint stress Monoamines
Fruits of Fructus Schisandrae were used as sedatives and hypnotics in traditional Chinese medicine for a long history. In this study, we investigated the effects of schisandra lignans extract (SLE) on anxiety disorder in restraint-stressed mice using light-dark (L-D) test. The influences of restraint stress on the levels of monoamines: noradrenaline (NE), dopamine (DA) and serotonin (5-HT) in cerebral cortex, as well as plasma corticosterone (CORT) were studied in mice. The HPLC fingerprint of SLE was recorded and the percentage composition of Schisandra lignans was determined as 82.63%. In L-D test, it was found out that 18 h of restraint stress significantly decreased the anxiolytic parameters (explorative behaviors, e.g. number of entries, time spent) in light area indicating high state of anxiety in stressed mice. In addition, restraint stress elevated NE, DA, and 5-HT levels in cerebral cortex of anxiety mice. Plasma CORT level was also increased. Oral administration of SLE (100 and 200 mg/kg/day, 8 days) emolliating the level of stress-induced anxiety by significantly increasing the anxiolytic parameters mentioned above. We also observed decreases in cerebral cortex monoamines levels, as well as plasma CORT level in stressed mice. These results suggested that SLE reversed stress-induced anxiety level, changes of cortex monoamine transmitters and plasma CORT. The anxiolytic effects of SLE might be related to its anti-stress activity by modulation of hyperactive HPA axis.
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The health burden of stress-related diseases, including depression and anxiety disorders (Olivier et al. 2003), is rapidly increasing, whereas the ranges of available pharmacotherapies to treat these disorders are limited and suboptimal with regard to efficacy and tolerability. Studies have shown that herbal drugs, such as Fructus Schisandrae (Panossian and Wikman 2008) exert tonic and sedative effects. Fructus Schisandrae (F. Schisandrae), fruit of Schisandra chinensis (Turcz.) Baill, is regarded as a top grade herb in tradi-tional Chinese and Russian medicine which contains a variety of bioactive lignans. In traditional Chinese medicine, Schisandra lig-nans have been used to treat insomnia (Chen and Liao 1993; Zhu 1998). In recent years, many studies had demonstrated that extract of Schisandra lignans possesses various beneficial pharmacological effects such as anti-hepatitis, anti-inflammation, sedative and anti-stress (Lee et al. 2007; Panossian et al. 2007). However, no researches concerning its therapeutic effects on anxiety disorders induced by stress were reported. In addition, anxiety is thought to be a negative emotion caused by stress such as restraint or immobility stress (Hata et al. 2000). Preview reports showed that restraint stress involves mental stress responses and is often used to study the pathological processes of anxiety (Gregus et al. 2005). Thus, the present study was conducted to investigate the anxiolytic effects of Schisandra lignans extract (SLE) on restraint stress-induced anxiety mice using light-dark (L-D) test, and the influences on the levels of monoamines noradrenaline (NE), dopamine (DA) and serotonin (5-HT) in cerebral cortex of mice, as well as the plasma corticosterone (CORT) level.