Neolignans from Schisandra wilsoniana and their anti-human immunodeficiency virus-1 activities

Neuroprotective Effect of Schisandra Chinensis on Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Induced Parkinsonian Syndrome in C57BL/6 Mice

Schisandra chinensis (Turcz.) Baill. (S. chinensis) is a well-known botanical medicine and nutritional supplement that has been shown to have potential effects on neurodegeneration. To investigate the potential neuroprotective effect of S. chinensis fruit extract, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was used to induce behavioral disorders and dopaminergic neuronal damage in mice, and biochemical indicators were examined. Male C57BL/6 mice were used to establish the MPTP-induced parkinsonian syndrome model. Open field and rotarod tests were performed to evaluate the overall manifestation of motor deficits and rodent motor coordination. The mice were divided into 8 groups as follows: normal control; MPTP alone (25 mg/kg, i.p.); S. chinensis extract pretreatment (0.5, 1.5, 5 g/kg, p.o.); and S. chinensis extract treatment (0.5, 1.5, 5 g/kg, p.o.). Liquid chromatography coupled to electrochemical detection was used to monitor neurochemicals in the striatum. Tyrosine hydroxylase content was measured by immunohistochemistry, and biochemical antioxidative indicators were used to evaluate the potential neuroprotective effects of S. chinensis fruit extract. The results demonstrated that treatment with S. chinensis fruit extract ameliorated MPTP-induced deficits in behavior, exercise balance, dopamine level, dopaminergic neurons, and tyrosine hydroxylase-positive cells in the striatum of mice. Among the pretreated and treatment groups, a high dose of S. chinensis fruit extract was the most effective treatment. In conclusion, S. chinensis fruit extract is a potential herbal drug candidate for the amelioration and prevention of Parkinson's disease.

Pharmacokinetics of Schizandrin and Its Pharmaceutical Products Assessed Using a Validated LC-MS/MS Method

Schisandra chinensis has been used as an important component in various prescriptions in traditional Chinese medicine and, more recently, in Western-based medicine for its anti-hepatotoxic effect. The aim of this study was to develop a selective, rapid, and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method for pharmacokinetic studies of schizandrin in rats. Liquid-liquid extraction was used for plasma sample preparation. A UHPLC reverse-phase C18e column (100 mm × 2.1 mm, 2 μm) coupled with a mobile phase of methanol-0.1% formic acid (85:15, v/v) was used for sample separation. A triple quadrupole tandem mass spectrometer was used to detect the analytes in the selected reaction monitoring mode. The linear range of schizandrin in rat plasma was 5.0–1000 ng/mL (r² > 0.999), with a lower limit of quantification of 5 ng/mL. The method was validated with regard to accuracy, intra-day and inter-day precision, linearity, stability, recovery, and matrix effects in rat plasma, which were acceptable according to the biological method validation guidelines developed by the FDA. This method was successfully applied to a pharmacokinetic study after oral administration of 3 g/kg and 10 g/kg of Schisandra chinensis products, which yielded a maximum concentration of schizandrin of 0.08 ± 0.07 and 0.15 ± 0.09 μg/mL, respectively. A parallel study design was used to investigate the oral bioavailability of single compound of schizandrin and the herbal extract, the single compound of pure schizandrin (10 mg/kg, i.v.), pure schizandrin (10 mg/kg, p.o.), and the herbal extract of Schisandra chinensis (3 g/kg and 10 g/kg, p.o.) were given individually. The dose of Schisandra chinensis (3 g/kg) equivalent to schizandrin (5.2 mg/kg); the dose of Schisandra chinensis (10 g/kg) equivalent to schizandrin (17.3 mg/kg). The result demonstrated that the oral bioavailability of schizandrin was approximately 15.56 ± 10.47% in rats, however the oral bioavailability of herbal extract was higher than single compound. The method was successfully applied to the pharmacokinetic study of pure schizandrin after oral administration of its pharmaceutical industry products in rats.