[Identify metabolites of Piper longum alkaloids in feces and urine of rat by HPLC-FT-MS].

The metabolites were detected in feces and urine of rats orally administrated alkaloids of Piper longum by using high performance liquid chromatography coupled with a Fourier Transform ion cyclotron resonance mass spectrometer (HPLC-FT-MS). According to the mass spectrometric data and reported literature, the structures of metabolites were identified. Several metabolites were analyzed and belonged to piperine, piperanine, piperlonguminine, Δα,ß-dihydropiperlonguminine and pellitorine, respectively. The metabolites of alkaloids from P. longum alkaloids were produced through Ⅰ phase and Ⅱ phase metabolism reaction, and were excreted with urination and defecation. The approach provided a rapid method for characterizing the metabolites of P. longum alkaloids and gave the truly active structures and the action mechanism of their neuroprotective effects.

Neuroprotective effects of alkaloids from Piper longum in a MPTP-induced mouse model of Parkinson's disease.

CONTEXT: Alkaloids of Piper longum L. (Piperaceae) (PLA) include piperine and piperlonguminine. Piper longum and piperine have multiple biological properties including antioxidant activity. OBJECTIVE: The present study investigated the neuroprotective effects of PLA in a MPTP-induced mouse model of Parkinson's disease. MATERIALS AND METHODS: PLA was prepared by extracting the dry seed of P. longum using 85% ethanol. Adult male C57BL/6 mice were divided into eight groups of 12 rats each. Experimental and control groups received an equivalent volume of saline, 0.5% CMC-Na, and 0.1% Tween 80, treated groups received oral PLA (30, 60, and 120 mg/kg), other groups treated with piperine (60 mg/kg) or Madopar (50 mg/kg). The PLA prevention group (PLA-Pr) administrated PLA (120 mg/kg) for 1 week before MPTP challenged. Except for the PLA-Pr group, others were treated for seven consecutive weeks. Parkinson's disease was induced by injecting MPTP intraperitoneally (25 mg/kg) twice weekly for five consecutive weeks. Dopaminerigic (DA) neurons and their metabolism were detected by UFLC-MS/MS. Tyrosine hydroxylase (TH)-immunohistochemistry assay and Western blotting were performed. The antioxidant enzymatic levels were determined by kit-based assays. RESULTS: The LD50 value of PLA was determined at 1509 mg/kg of body weight. PLA (60 mg/kg) can significantly increase total movement time and distance (p < 0.05), increase levels of DA (p < 0.05) and DOPAC (p < .05), increase glutathione (GSH) level and superoxide dismutase (SOD) activity (p < 0.05), and decrease the lipid peroxidation of malondiadehycle (MDA) (p < 0.05) in PLA-treated groups as compared with the control group. DISCUSSION AND CONCLUSION: Our results indicate that PLA possesses neuroprotective effects and has ameliorative properties in dopaminergic neurons.

Identification and simultaneous quantification of five alkaloids in Piper longum L. by HPLC-ESI-MS(n) and UFLC-ESI-MS/MS and their application to Piper nigrum L.

A simple, effective and suitable UFLC-ESI-MS/MS method was firstly developed to simultaneously determine five characteristic constituents (piperine, piperlonguminine, Δα,ß-dihydropiperlonguminine, pellitorine and piperanine) of Piper longum L. The total alkaloids of P. longum L. was prepared. The alkaloid contents of Piper nigrum L. and P. longum L. were compared. The analysis was carried out in multiple reaction monitoring scan mode. The method showed a good specificity, linearity (R(2)>0.995), stability (RSD<2.53%), repeatability (RSD<2.58%), and recovery (90.0-103.5%). The limits of detection and limits of quantification of five alkaloids were in the range of 0.02-0.03 and 0.05-0.10 ng/mL, respectively. The intra- and inter-day precision was less than 9.30% and 9.55%, respectively. The validation results confirmed that the method could simultaneously determine the target alkaloids in the sample. Furthermore, the identities of the alkaloids were verified by HPLC-ESI-MS/MS. Compared with P. nigrum, P. longum had lower piperine content but was enriched in the other four alkaloids.

[Protective effect of alkaloids from Piper longum in rat dopaminergic neuron injury of 6-OHDA-induced Parkinson's disease].

OBJECTIVE: To discuss the protective effect of alkaloids from Piper longum (PLA) in rat dopaminergic neuron injury of 6-OHDA-induced Parkinson's disease and its possible mechanism. METHOD: The rat PD model was established by injecting 6-OHDA into the unilateral striatum with a brain solid positioner. The PD rats were divided into the PLA group (50 mg x kg(-1) x d(-1)), the madorpa group (50 mg x kg(-1) x d(-1)) and the model group, with 15 rats in each group. All of the rats were orally given drugs once a day for 6 weeks. Meanwhile, other 15 rats were randomly selected as the sham operation group, and only injected with normal saline in the unilateral striatum. The behavioral changes were observed with the apomorphine (APO)-induced rotation and rotary rod tests. The number of tyrosine hydroxylase (TH)-positive cells in rat substantia nigra and the density of TH-positive fibers in striatum were detected by tyrosine hydroxylase immunohistochemistry. The content of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione (GSH), catalase (CAT), malondialdehyde (MDA), nitric oxide (NO) and nitric oxide synthase (NOS) in rat substantia nigra and striatum were measured by the spectrophotometric method. RESULT: After being induced by APO, PD rats showed obvious rotation behaviors, with decreased time stay on rotary rod and significant reduction in the number of TH-positive cells in sustantia nigra and the density of TH-positive fibers in striatum. The activities of SOD, GSH-Px, CAT, the content of GSH and the total antioxidant capacity significantly decreased, whereas the activities of NOS and the content of MDA, NO significantly increased. PLA could significantly improve the behavioral abnormality of PD rats and increase the number of TH-positive cells in sustantia nigra and the density of TH-positive fibers in striatum. It could up-regulate the activities of SOD, GSH-Px, CAT, the content of GSH and the total antioxidant capacity, and decrease the content of NOS and the content of MDA, NO. CONCLUSION: Alkaloids from P. longum shows the protective effect in substantia nigra cells of 6-OHDA-induced PD model rats. Its mechanism may be related with their antioxidant activity.

A new flavanone from the aerial parts of Penthorum chinense.

A new flavanone, 5-methoxy-pinocembrin-7-O-ß-D-glucoside (1), together with six known compounds, quercetin-3-O-ß-D-xyloside (2), quercetin-3'-O-α-L-rhamnoside (3), quercetin (4), pinocembrin-7-O-ß-D-glucoside (5), pinocembrin (6), gallic acid (7), were isolated and identified from the aerial parts of Penthorum chinense. Compounds 2 and 3 were isolated from this plant for the first time.