Chinese Medicinal Herb Polygonum Cuspidatum Research Articles

Off-line comprehensive two-dimensional reversed-phase countercurrent chromatography with high-performance liquid chromatography: Orthogonality in separation of Polygonum cuspidatum Sieb. et Zucc.

Off-line comprehensive two-dimensional reversed-phase countercurrent chromatography with high-performance liquid chromatography was investigated in separation of crude ethanol extract from traditional Chinese medicinal herb Polygonum cuspidatum Sieb. et Zucc. Two-dimensional contour plots for countercurrent chromatography with high-performance liquid chromatography was obtained after comprehensive separation was completed. Total peak capacity was evaluated and approximately 810 peaks were obtained through a comprehensive two-dimensional separation. A highly orthogonality of 52.23% and a large separation space occupancy of 88.86% were achieved. Meanwhile, it was found that several components could be well separated by countercurrent chromatography while they could not be separated by high-performance liquid chromatography, and vice versa, which further indicated the orthogonality of the two separation methods. The off-line comprehensive two-dimensional countercurrent chromatography with high-performance liquid chromatography provided a promising and powerful method for separation of complex natural products.

Preparative separation of bioactive polyphenol resveratrol from Polygonum cuspidatum Sieb. et Zucc. by pH‐zone‐refining countercurrent chromatography

AbstractpH‐zone‐refining countercurrent chromatography has been well explored for separation of organic acids and bases from natural products. However, it has not been investigated in separation of polyphenol compounds so far. In the present work, pH‐zone‐refining countercurrent chromatography was successfully applied in preparative separation of a polyphenol bioactive component resveratrol along with a hydroxyanthraquinone emodin, from traditional Chinese medicinal herb Polygonum cuspidatum using a self‐made type‐J countercurrent chromatographic apparatus. Resveratrol is a polyphenol component with a wide arrange of bioactivities. A biphasic solvent system composed of n‐hexane/ethyl acetate/ethanol/water (3:5:2:6, v/v) was selected, in which 10 mmol L−1 of trifluoroacetic acid was added in the organic phase as the retainer while 10 mmol L−1 of ammonia was added in the aqueous phase as the eluter. The loading sample could reach 300 mg in a single run, in which 35 mg of resveratrol and 156 mg of emodin could be obtained with a high purity of 96.0 and 93.2%, respectively, as determined by HPLC. Meanwhile, an interesting elution sequence for resveratrol and emodin by pH‐zone‐refining countercurrent chromatography was found and discussed compared with conventional countercurrent chromatography. The results showed that pH‐zone‐refining countercurrent chromatography could be used in preparative separation of polyphenol component. An efficient alternative method for preparative separation of resveratrol from Polygonum cuspidatum was established.

2‐Methoxystypandrone inhibits signal transducer and activator of transcription 3 and nuclear factor‐κB signaling by inhibiting Janus kinase 2 and IκB kinase

Constitutive activation of the signal transducer and activator of transcription 3 (STAT3) or the nuclear factor-κB (NF-κB) pathway occurs frequently in cancer cells and contributes to oncogenesis. The activation of Janus kinase 2 (JAK2) and IκB kinase (IKK) are key events in STAT3 and NF-κB signaling, respectively. We have identified 2-methoxystypandrone (2-MS) from a traditional Chinese medicinal herb Polygonum cuspidatum as a novel dual inhibitor of JAK2 and IKK. 2-MS inhibits both interleukin-6-induced and constitutively-activated STAT3, as well as tumor necrosis factor-α-induced NF-κB activation. 2-MS specifically inhibits JAK and IKKβ kinase activities but has little effect on activities of other kinases tested. The inhibitory effects of 2-MS on STAT3 and NF-κB signaling can be eliminated by DTT or glutathione and can last for 4 h after a pulse treatment. Furthermore, 2-MS inhibits growth and induces death of tumor cells, particularly those with constitutively-activated STAT3 or NF-κB signaling. We propose that the natural compound 2-MS, as a potent dual inhibitor of STAT3 and NF-κB pathways, is a promising anticancer drug candidate.

The effects of Polygonum cuspidatum extract on wound healing in rats

Aim of the studyPolygonum cuspidatum has long been used as a traditional medicine inducing wound healing. In this study, the extract from the Chinese medicinal herb Polygonum cuspidatum was investigated on its wound healing activity, in order to obtain an accurate elucidation of its traditional use value. Materials and methodsAfter creating wound healing model on the back of rats, the extract from the Chinese medicinal herb Polygonum cuspidatum was applied. Wound healing rates were calculated at 3, 7, 14, and 21days after the wounding, and tissues were harvested at 1, 3, 7, 14 and 21days for histological and immunohistochemistry analysis. The stages of wound granulation tissues were evaluated histopathologically. The expression of TGF-β1 was determined by immunohistochemically. ResultsWound healing rates were significantly higher at 3, 7, 14 and 21days in the extract group than in the control (p<0.05). Histological results showed more well-organized bands of collagen, more fibroblasts and hair follicle and less inflammatory cells in the extract group. The immunohistochemical results revealed that TGF-β1 increased in the extract group on day 1, 3 and 7 post-wounding (p<0.05). ConclusionThe present study has shown that the extract from the Chinese medicinal herb Polygonum cuspidatum possesses wound healing activity, and thus provided the evidence for its traditional use value.

Neuroprotective effects of emodin in rat cortical neurons against β-amyloid-induced neurotoxicity

Accumulation of β-amyloid protein (Aβ) in the brain plays an important role in the pathogenesis of Alzheimer's disease (AD). In this study, the neuroprotective effect of emodin extracted from the traditional Chinese medicinal herb Polygonum cuspidatum Sieb. et Zucc against Aβ 25 – 35-induced cell death in cultured cortical neurons was investigated. We found that pre-treatment with emodin prevented the cultured cortical neurons from β-amyloid-induced toxicity. The preventive effect of emodin was blocked by pre-treatment with a phosphatidylinositol-3-kinase (PI3K) pathway inhibitor LY294002 or an estrogen receptor (ER) specific antagonist ICI182780, but not by pre-treatment with an extracellular signal-related kinases (ERK) inhibitor U0126. Furthermore, we found that emodin exposure induced the activation of the Akt serine/threonine kinase and increased the level of Bcl-2 expression. Moreover, the application of emodin for 24 h was able to induce the activation of Aβ 25 – 35-suppressed Akt and decrease the activation of the Jun-N-terminal kinases (JNK), but not of ERK. Interestingly, the up-regulation of Akt and Bcl-2 did not occur in the presence of LY294002 or ICI182780, suggesting that emodin-up-regulated Bcl-2 is mediated via the ER and PI3K/Akt pathway. Taken together, our results suggest that emodin is an effective neuroprotective drug and is a viable candidate for treating AD.

Neuroprotective effects of emodin in rat cortical neurons against β-amyloid-induced neurotoxicity

Accumulation of β-amyloid protein (Aβ) in the brain plays an important role in the pathogenesis of Alzheimer's disease (AD). In this study, the neuroprotective effect of emodin extracted from the traditional Chinese medicinal herb Polygonum cuspidatum Sieb. et Zucc against Aβ 25–35-induced cell death in cultured cortical neurons was investigated. We found that pre-treatment with emodin prevented the cultured cortical neurons from β-amyloid-induced toxicity. The preventive effect of emodin was blocked by pre-treatment with a phosphatidylinositol-3-kinase (PI3K) pathway inhibitor LY294002 or an estrogen receptor (ER) specific antagonist ICI182780, but not by pre-treatment with an extracellular signal-related kinase (ERK) inhibitor U0126. Furthermore, we found that emodin exposure induced the activation of the Akt serine/threonine kinase and increased the level of Bcl-2 expression. Moreover, the application of emodin for 24 h was able to induce the activation of Aβ 25–35-suppressed Akt and decrease the activation of the Jun-N-terminal kinases (JNK), but not of ERK. Interestingly, the up-regulation of Akt and Bcl-2 did not occur in the presence of LY294002 or ICI182780, suggesting that emodin-up-regulated Bcl-2 is mediated via the ER and PI3K/Akt pathway. Taken together, our results suggest that emodin is an effective neuroprotective drug and is a viable candidate for treating AD.

Resveratrol Attenuates Adenosine Diphosphate-Induced Platelet Activation by Reducing Protein Kinase C Activity

Inappropriate platelet activation is the key point of thrombogenesis. The aim of the present study was to investigate the effects of resveratrol (RESV), a compound extracted from the Chinese medicinal herb Polygonum cuspidatum sieb et Zucc, on the platelet activation induced by adenosine diphosphate (ADP) and its possible mechanism. The percentage of platelet aggregation and surface P-selectin-positive platelets, and the activity of protein kinase C (PKC) of platelet were observed with platelet aggregometer, flow cytometry and phosphorimaging system, respectively. RESV at 25, 50 and 100 microM showed anti-platelet aggregation and inhibition of surface P-selectin-positive platelets in a concentration-dependent manner. RESV (50 microM) inhibited the activity of PKC in the membrane fraction of platelets and decreased the percentage of membrane associated PKC activity in total PKC activity. Moreover, DL-erythro-1,3-Dihydroxy-2-aminooctadecane, an elective protein kinase C inhibitor (PKCI), and RESV had additive effects of inhibiting the percentage of platelet aggregation and surface P-selectin-positive platelets. It is suggested that RESV may inhibit platelet aggregation, the percentage of surface P-selectin-positive platelets and subsequent thrombus formation. The mechanisms may be partly relative to the decrease of the activity of PKC of platelets.

Neuroprotective effects of emodin-8- O-β- d-glucoside in vivo and in vitro

Emodin-8- O-β- d-glucoside extracted from the traditional Chinese medicinal herb Polygonum cuspidatum Sieb. et Zucc is widely used to treat acute hepatitis possibly by antioxidative mechanisms. The present study was designed to investigate whether emodin-8- O-β- d-glucoside exerted neuroprotective effects on the focal cerebral injury induced by ischemia and reperfusion in vivo and on the neuronal damage induced by glutamate in vitro, and to study the possible mechanisms. Male Wistar rats were used to establish the model of ischemia and reperfusion. The behavioral test was performed and the cerebral infarction area was assessed in the brain slices stained with 2% 2,3,5-triphenyl tetrazolium chloride to evaluate the neuroprotective effects of emodin-8- O-β- d-glucoside. Superoxide dismutase (SOD) activity, total antioxidative capability and malondialdehyde (MDA) level in the brain tissue were determined with spectrophotometrical methods to probe the primary mechanisms of emodin-8- O-β- d-glucoside. In vitro, the neuroprotective effects of emodin-8- O-β- d-glucoside were tested in the cultured cortical cells of fetal rats exposed to glutamate. Emodin-8- O-β- d-glucoside concentration in plasma and brain tissue was also measured to examine distribution of emodin-8- O-β- d-glucoside in the brain. The results showed that the treatment of rats with emodin-8- O-β- d-glucoside reduced the neurological deficit score and the cerebral infarction area, increased SOD activity and total antioxidative capability, and decreased MDA level in the brain tissue in dose-dependent way. Emodin-8- O-β- d-glucoside also inhibited the neuronal damage induced by glutamate. Besides, emodin-8- O-β- d-glucoside was able to penetrate blood-brain barrier and distribute in the brain tissue. These findings demonstrate that emodin-8- O-β- d-glucoside is able to provide neuroprotection against cerebral ischemia-reperfused injury and glutamate induced neuronal damage through exerting antioxidative effects and inhibiting glutamate neurotoxicity.

One-Step Purification of Resveratrol and Polydatin from Polygonum cuspidatum (Sieb. &amp; Zucc.) by Isocratic Hydrogen Bond Adsorption Chromatography on Cross-Linked 12% Agarose

Resveratrol and polydatin (piceid), the major active components of the traditional Chinese medicinal herb Polygonum cuspidatum (Sieb. & Zucc.), have been separated and purified from crude root extracts in one step by isocratic hydrogen bond adsorption chromatography on cross-linked 12% agarose (Superose™ 12 HR 10/30). Separation was achieved by step-wise elution with mobile phases composed of mixtures of ethanol and acetic acid: 0–75 mL, 10% ethanol, 10% acetic acid; 75–150 mL, 20% ethanol, 20% acetic acid; 150–250 mL, 30% ethanol, 30% acetic acid. At a sample load of 40 mg crude extract dissolved in 0.5 mL mobile phase (corresponding to a load of 1.7 mg mL−1 gel) a resveratrol purity of about 96% with a recovery of 61% was obtained by proper peak cutting.

Supercritical CO2 extraction of emodin and physcion from Polygonum cuspidatum and subsequent isolation by semipreparative chromatography

Emodin and physcion are abundant anthraquinone compounds found in the traditional Chinese medicinal herb Polygonum cuspidatum Sied. et Zucc. In this paper, emodin and physcion were successfully extracted with supercritical CO2 plus ethanol modifier after the extraction conditions were optimized with uniform design-sequential optimization. Results showed that the ethanol modifier concentration was the main factor for the effective extraction of the emodin. The optimal extraction condition was obtained: 20 MPa, 30 degrees C, and 95% ethanol, at which the yields of emodin and physcion were 0.616 and 0.178 g/100 g, respectively. The yield obtained by supercritical fluid extraction (SFE) was a little lower than that obtained by sonication extraction (SE). The crude extract obtained by SFE was further isolated and purified by semipreparative chromatography with the mobile phase composed of methanol-water (90:1, v/v). Emodin and physcion were obtained with purity 98.6 and 99.1%, respectively, when determined by HPLC, and identification was performed by retention time and UV spectra of the standards. The result suggested that SFE is an alternative and promising method for extraction of the two compounds from P. cuspidatum owing to its environment-friendly properties and fewer coextracts.

Preparative isolation and purification of five compounds from the Chinese medicinal herb Polygonum cuspidatum Sieb. et Zucc by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) was applied to the separation and purification of five compounds from the Chinese medicinal herb Polygonum cuspidatum Sieb. et Zucc. The crude extracts from P. cuspidatum Sieb. et Zucc were treated with light petroleum–ethyl acetate–methanol–water (2:5:4:6, v/v). Sample 1 was obtained from the lower phase and sample 2 from the upper phase. The sample 1 was separated with light petroleum–ethyl acetate–water (1:5:5, v/v) and yielded 19.3 mg of piceid, 17.6 mg of anthraglycoside B from 200 mg of sample 1. The sample 2 was separated with light petroleum–ethyl acetate–methanol–water (3:5:4:6, v/v) and light petroleum–ethyl acetate–methanol–water (3:5:7:3, v/v) in a gradient elution and yielded 18.5 mg of resveratrol, 35.3 mg of emodin and 8.2 mg of physcion from 220 mg of sample 2. The purity of each compound is over 95% as determined by HPLC. The chemical structures of these components were identified by 1H NMR and 13C NMR.

Determination of trans-Resveratrol in wines, herbs and health food by capillary electrophoresis with electrochemical detection

A method based on capillary electrophoresis with electrochemical detection (CE–ED) was developed for the determination of trans-Resveratrol in wines, Chinese medicinal herb Polygonum cuspidatum Sied. et Zucc., and Zijin capsule. The effects of some important factors such as injection time, and applied potential to working electrode were investigated. Operated in a wall-jet configuration, a 300 μm diameter carbon-disk electrode was used as the working electrode, which exhibits good response at +0.85 V (vs. SCE) for trans-Resveratrol. Linearity was obtained in the concentration range from 1.0×10 −4 to 5.0×10 −7 g/ml. The detection limit (S/N=3) was 5.96×10 −8 g/ml. This proposed method has been successfully applied to analyze several actual samples with satisfactory assay results.