Paeonol reduced cerebral infarction involving the superoxide anion and microglia activation in ischemia-reperfusion injured rats

Paeonol from Paeonia suffruticosa prevents TNF-alpha-induced monocytic cell adhesion to rat aortic endothelial cells by suppression of VCAM-1 expression

Paeonol (2'-hydroxy-4'-methoxyacetophenone), the main active compound of the radix of Paeonia suffruticosa, has been reported to have a beneficial effect in prevention and treatment of cardiovascular diseases. Vascular cell adhesion molecule-1 (VCAM-1), plays a crucial role in case of early inflammatory responses, including atherosclerosis. In this study, we investigated the effect of paeonol on TNF-alpha-induced VCAM-1 expression in rat aortic endothelial cells (RAECs). The VCAM-1 expression in paeonol treated RAECs was measured. Paeonol inhibited TNF-alpha-induced VCAM-1 expression in a concentration-dependent manner. TNF-alpha induced p38 and extracellular signal-regulated kinase 1/2 (ERK1/2) activities that contributed to VCAM-1expression was obviously attenuated after pre-treating RAECs with paeonol. The decrease of VCAM-1 expression by paeonol pretreatment led to a reduction of monocytes adhesion to RAECs. Taken together, our results demonstrated that paeonol inhibited VCAM-1 expression by the attenuation of p38 and ERK1/2 signal transduction pathways. We concluded that paeonol had the potential therapeutic development for use in anti-inflammatory and vascular disorders.

Paeonol exerts anti-angiogenic and anti-metastatic activities through downmodulation of Akt activation and inactivation of matrix metalloproteinases

Paeonol (2'-hydroxy-4'-methoxyacetophenone) is known to possess anti-inflammatory and anti-proliferative activities. Recently there is evidence that anti-inflammatory agents may be useful in the setting of angiogenesis-related diseases. Thus in the present study the anti-angiogenic activity of paeonol and its mechanism were investigated in vitro and in vivo. Paeonol significantly inhibited proliferation of basic fibroblast growth factor (bFGF)-stimulated human umbilical vein endothelial cells (HUVECs). Paeonol also significantly inhibited migration and tube formation of bFGF-stimulated HUVECs in vitro. In addition, paeonol significantly suppressed neovessel formation on bFGF-treated chick chorioallantoic membrane (CAM) and disrupted bFGF-induced neovascularization in Matrigel plug assay in vivo. Furthermore, paeonol downregluated Akt phosphorylation in bFGF-stimulated HUVECs and reduced expression of matrix metalloproteinases-2 and -9 in HT1080 human fibrosarcoma cells. The Akt inhibitor LY294002 synergistically potentiated paeonol-induced inactivation of Akt and vascular endothelial growth factor in bFGF-treated HUVECs. Taken together, these findings suggest that paeonol can be a potent suppressor of angiogenesis and metastasis partially through inhibition of Akt signaling pathway and matrix metalloproteinase activity.

Comparative pharmacokinetic study of paeoniflorin after oral administration of pure paeoniflorin, extract of Cortex Moutan and Shuang-Dan prescription to rats

Shuang-Dan (SD) is a traditional Chinese prescription containing Cortex Moutan and Radix Salviae miltiorrhizae and commonly used for treating cardiovascular disease. Paeoniflorin is a main effective ingredient of Cortex Moutan and the pharmacokinetic differences of paeoniflorin following oral administration of pure paeoniflorin, Cortex Moutan extract and SD decoction to rats were studied with approximately the same dose of 30mg/kg paeoniflorin. At different time points (5, 10, 15, 30, 45, 60, 90, 120, 150, 210, 270, 360, 450min), plasma concentration of paeoniflorin was determined using a simple and rapid HPLC-MS method. Unpaired student's t-test was used for the statistical comparison. A bimodal phenomenon was observed in the plasma profile after oral administration of Cortex Moutan extract. Statistically significant increase (P<0.05) in pharmacokinetic parameters of paeoniflorin including AUC(0-t), AUC(0-infinity) and MRT were obtained after oral administration of Cortex Moutan or SD decoction comparing with pure paeoniflorin. The investigation showed that among all calculated parameters, AUC(0-t), AUC(0-infinity), MRT, k(e) and T(1/2), there were no significant differences between the two decoctions. The results indicated that the reason which delay the elimination of paeoniflorin and enhance its bioavailability might be some ingredients in Cortex Moutan extract.

Puerarin protects against ischemic brain injury in a rat model of transient focal ischemia

OBJECTIVES

This study examines the efficacy of puerarin, a drug used in traditional Chinese medicine, in attenuating ischemic brain injury after cerebral ischemia and reperfusion, and explores possible mechanisms underlying neuroprotective effects.

METHODS

The animal model of ischemia/reperfusion injury was induced by middle cerebral artery occlusion for 2 hours followed by up to 72 hour reperfusion. The rats were randomly assigned into four groups (n=6/group): puerarin at 100, 200 and 400 mg/kg or saline, administered intraperitoneally. Neurological outcome and infarct volume by 2% triphenyl tetrazolium chloride staining were determined 72 hours after reperfusion. Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling staining was used to detect the cell damage of brains (n=5/group). Erythropoietin activation was detected by enzyme-linked immunosorbent assay (n=5/group).

RESULTS

Compared with the vehicle saline group, puerarin decreased infarction volume at doses of 200 mg/kg (p=0.045) and 400 mg/kg (p=0.0002), but not at 100 mg/kg (p=0.387). Functional neurological outcome was improved with puerarin at 400 mg/kg (p=0.015), but not at 100 mg/kg (p=0.68) or 200 mg/kg (p=0.056). Puerarin significantly decreased the terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling staining cells compared with the vehicle group 4, 24 and 72 hours after reperfusion. The erythropoietin activity was higher in puerarin treated group compared with the vehicle group.

DISCUSSION

Puerarin has neuroprotection effects in rats at doses of 200 and 400 mg/kg, administered intraperitoneally after transient middle cerebral artery occlusion which may be partly due to activation of erythropoietin activity.

Panax Notoginseng Burk attenuates impairment of learning and memory functions and increases ED1, BDNF and beta-secretase immunoreactive cells in chronic stage ischemia-reperfusion injured rats

Panax Notoginseng Burk (PN) has been reported to improve blood circulation, as well as learning and memory functions. The purpose of the present study was to investigate the effect of PN on learning and memory functions in chronic cerebral infarct rats. A cerebral infarct animal model was established by blocking the blood flow of both common carotid arteries and right middle cerebral artery for 90 min followed by reperfusion for 4 weeks. PN (0.5 g/kg) was administered orally 3 days per week for 4 weeks, whereas the control group provided bait and water only. The learning and memory functions were estimated by measuring how successful rats were able to negotiate an 8-arm radial maze test; the test was performed after operation once a week for 4 weeks. Finally, the rats were sacrificed and their brains were removed. The brains were sectioned and analyzed for ED1, glial fibrillary acid protein (GFAP), nuclear factor-kappaB, and brain derivative neurotrophin factor (BDNF) and beta-secretase by immunostaining. Cerebral infarct rats given PN were able to successfully navigate the 8-arm radial maze test four weeks after cerebral infarction. PN also increased ED1, BDNF and beta-secretase immunoreactive cells, but did not increase GFAP and NF-kappaB immunoreactive cells. PN attenuated the reduction in learning and memory functions induced by cerebral infarction in cerebral ischemia-reperfusion injured rats; it also increased the amount of activated microglia and BDNF. These data suggest that the effect of PN, at least in part, is closely related to the increase in BDNF that was generated by activated microglia. The effect that PN has on astrocytes, NF-kappaB and beta-secreatase immunoreactive cells requires further study.

Antiallergic effect of the root of Paeonia lactiflora and its constituents paeoniflorin and paeonol

The root of Paeonia lactiflora PALL (PL, Family Paeoniaceae) has been used frequently as an antipyretic and anti-inflammatory agent in traditional medicines of Korea, China and Japan. To evaluate antiallergic effect of PL, we isolated its main constituents, paeoniflorin and paeonol, and evaluated in vivo their inhibitory effects against passive cutaenous anaphylaxis (PCA) reaction induced by IgE-antigen complex and scratching behaviors induced by compound 48/80. PL, paeoniflorin and paeonol potently inhibited PCA reaction and scratching behaviors in mice. Paeoniflorin exhibited the most potent inhibition against scratching behaviors and the acetic acid-induced writhing syndrome in mice. Paeonol most potently inhibited PCA reaction and mast cells degranulation. These findings suggest that PL can improve IgE-induced anaphylaxis and scratching behaviors, and may be due to the effect of its constituents, paeoniflorin and paeonol.

Peroxynitrite mediates high glucose-induced osteoblast apoptosis

High glucose (HG) state is closely related to diabetic complications, and among these one main pathogenesis involves apoptosis of important functional cells. However, the mechanism of osteoblast (OB) apoptosis induced by HG state is not clear. Peroxynitrite (ONOO-), the strongest oxidant, can mediate apoptosis in various kinds of cells, including OB. Therefore, this study was aimed at investigating whether HG state could induce OB apoptosis through ONOO-. Cultured OB from rat calvariae explanted from E21 fetuses were treated with HG solution. The ratio of OB apoptosis and ONOOcontent was assayed by TUNEL, flow cytometry, and immunohistochemistry. The results showed that HG state could induce ONOO- overformation (p<0.01), and excessive OB apoptosis (p<0.001). However, the HG-induced OB apoptosis could be attenuated by peonol, a potent scavenger of ONOO-. In conclusion, HG state might trigger excessive ONOO- formation, mediating OB apoptosis.