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1.  Laxative effects and mechanism of action of Brazilian green propolis 
Background
Brazilian green propolis is reported to have wide range of biological properties including antibacterial, anti-inflammatory, anti-influenza, and antioxidant activities. In the digestive system, a protective effect of propolis on gastric ulcer has been reported, but a laxative effect has not yet been reported. We investigated the effect and the mechanism of action of water and ethanol extracts of Brazilian green propolis.
Methods
We examined the laxative effect of propolis on stool frequency by administering orally an ethanol extract of propolis (EEP) or a water extract of propolis (WEP) at 10, 50, 100, or 500 mg/kg to normal mice. We then investigated the effects of propolis using constipation model mice induced by two types of drugs, loperamide (a μ opioid receptor agonist) and clonidine (an α-2 adrenergic receptor agonist). We also investigated the effects of WEP on gastrointestinal transit and contractional tension of the ileum to uncover the mechanism of action of WEP.
Results
Treatment with WEP, but not with EEP, significantly increased the weight of stools (p<0.01 at 500 mg/kg). WEP treatment significantly restored stool frequency and stool weight in clonidine-induced constipation model mice, but not in loperamide-induced constipation model mice. WEP treatment did not affect gastro-intestinal transit, but significantly increased the contractional tension of the isolated ileum of guinea pigs. This increase was inhibited by an acetylcholine receptor antagonist (atropine), but not by a 5-HT receptor antagonist (GR113808).
Conclusion
These findings indicate that WEP has laxative effects both in normal mice and in clonidine-induced constipation model mice. The laxative effects of WEP might be mediated by increased contractional tension of the ileum exerted at least in part via activation of an acetylcholine receptor.
doi:10.1186/1472-6882-12-192
PMCID: PMC3487869  PMID: 23088672
Propolis; Laxative; Acetylcholine receptor; Water extract
2.  Phosphodiesterase-III Inhibitor Prevents Hemorrhagic Transformation Induced by Focal Cerebral Ischemia in Mice Treated with tPA 
PLoS ONE  2010;5(12):e15178.
The purpose of the present study was to investigate whether cilostazol, a phosphodiesterase-III inhibitor and antiplatelet drug, would prevent tPA-associated hemorrhagic transformation. Mice subjected to 6-h middle cerebral artery occlusion were treated with delayed tPA alone at 6 h, with combined tPA plus cilostazol at 6 h, or with vehicle at 6 h. We used multiple imaging (electron microscopy, spectroscopy), histological and neurobehavioral measures to assess the effects of the treatment at 18 h and 7 days after the reperfusion. To further investigate the mechanism of cilostazol to beneficial effect, we also performed an in vitro study with tPA and a phosphodiesterase-III inhibitor in human brain microvascular endothelial cells, pericytes, and astrocytes. Combination therapy with tPA plus cilostazol prevented development of hemorrhagic transformation, reduced brain edema, prevented endothelial injury via reduction MMP-9 activity, and prevented the blood-brain barrier opening by inhibiting decreased claudin-5 expression. These changes significantly reduced the morbidity and mortality at 18 h and 7 days after the reperfusion. Also, the administration of both drugs prevented injury to brain human endothelial cells and human brain pericytes. The present study indicates that a phosphodiesterase-III inhibitor prevents the hemorrhagic transformation induced by focal cerebral ischemia in mice treated with tPA.
doi:10.1371/journal.pone.0015178
PMCID: PMC2997776  PMID: 21151895
3.  10-Hydroxy-2-decenoic Acid, a Major Fatty Acid from Royal Jelly, Inhibits VEGF-induced Angiogenesis in Human Umbilical Vein Endothelial Cells 
Vascular endothelial growth factor (VEGF) is reported to be a potent pro-angiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. Royal jelly (RJ) is a honeybee product containing various proteins, sugars, lipids, vitamins and free amino acids. 10-Hydroxy-2-decenoic acid (10HDA), a major fatty acid component of RJ, is known to have various pharmacological effects; its antitumor activity being especially noteworthy. However, the mechanism underlying this effect is unclear. We examined the effect of 10HDA on VEGF-induced proliferation, migration and tube formation in human umbilical vein endothelial cells (HUVECs). Our findings showed that, 10HDA at 20 µM or more significantly inhibited such proliferation, migration and tube formation. Similarly, 10 µM GM6001, a matrix metalloprotease inhibitor, prevented VEGF-induced migration and tube formation. These findings indicate that 10HDA exerts an inhibitory effect on VEGF-induced angiogenesis, partly by inhibiting both cell proliferation and migration. Further experiments will be needed to clarify the detailed mechanism.
doi:10.1093/ecam/nem152
PMCID: PMC2781774  PMID: 18955252
HUVECs; migration; proliferation; tube formation
4.  Proliferative diabetic retinopathy and relations among antioxidant activity, oxidative stress, and VEGF in the vitreous body 
Molecular Vision  2010;16:130-136.
Purpose
To investigate the relationships among antioxidant activities, oxidative stress, and vascular endothelial growth factor (VEGF) in the vitreous body and serum from proliferative diabetic retinopathy (PDR) patients.
Methods
In 21 patients with PDR and 21 controls with macular hole (MH), the VEGF and lipid peroxide (Nε-hexanoyl-lysine [HEL]) levels in the vitreous and serum were measured by enzyme-linked immunosorbent assay, while antioxidant capacity (potential antioxidant [PAO]) was measured by chemical reduction of Cu2+.
Results
Both the PAO and HEL levels in the vitreous and serum were significantly higher in PDR patients than in those with MH (both p<0.01). The VEGF concentrations in the vitreous were higher in PDR patients than in those with MH (p<0.01); however, the VEGF concentrations in the serum were not different between the two groups (p=0.95). Positive correlations were found between the PAO and VEGF concentrations and between the HEL and VEGF concentrations in the vitreous of both the PDR and the MH patients.
Conclusions
Our study revealed that the PAO, HEL, and VEGF concentrations in the vitreous were increased in PDR versus MH patients and that there were positive correlations among these factors. This is consistent with VEGF and lipid peroxide levels in the vitreous playing some role in the pathogenesis of PDR.
PMCID: PMC2817014  PMID: 20142849
5.  Bee products prevent VEGF-induced angiogenesis in human umbilical vein endothelial cells 
Background
Vascular endothelial growth factor (VEGF) is a key regulator of pathogenic angiogenesis in diseases such as cancer and diabetic retinopathy. Bee products [royal jelly (RJ), bee pollen, and Chinese red propolis] from the honeybee, Apis mellifera, have been used as traditional health foods for centuries. The aim of this study was to investigate the anti-angiogenic effects of bee products using human umbilical vein endothelial cells (HUVECs).
Methods
In an in vitro tube formation assay, HUVECs and fibroblast cells were incubated for 14 days with VEGF and various concentrations of bee products [RJ, ethanol extract of bee pollen, ethanol extract of Chinese red propolis and its constituent, caffeic acid phenethyl ester (CAPE)]. To clarify the mechanism of in vitro angiogenesis, HUVEC proliferation and migration were induced by VEGF with or without various concentrations of RJ, bee pollen, Chinese red propolis, and CAPE.
Results
RJ, bee pollen, Chinese red propolis, and CAPE significantly suppressed VEGF-induced in vitro tube formation in the descending order: CAPE > Chinese red propolis >> bee pollen > RJ. RJ and Chinese red propolis suppressed both VEGF-induced HUVEC proliferation and migration. In contrast, bee pollen and CAPE suppressed only the proliferation.
Conclusion
Among the bee products, Chinese red propolis and CAPE in particular showed strong suppressive effects against VEGF-induced angiogenesis. These findings indicate that Chinese red propolis and CAPE may have potential as preventive and therapeutic agents against angiogenesis-related human diseases.
doi:10.1186/1472-6882-9-45
PMCID: PMC2783019  PMID: 19917137
6.  Extracellular SOD and VEGF are increased in vitreous bodies from proliferative diabetic retinopathy patients 
Molecular Vision  2009;15:2663-2672.
Purpose
To evaluate the relationship between vascular endothelial growth factor (VEGF) and extracellular superoxide dismutase (EC-SOD) in vitreous body and serum in patients with proliferative diabetic retinopathy (PDR), and investigate the role of EC-SOD in PDR by evaluating its angiostatic effect, using an in vitro angiogenesis model. To investigate the role of EC-SOD in PDR by evaluating its angiostatic effect, using an in vitro angiogenesis model.
Methods
EC-SOD and VEGF concentrations in vitreous and serum samples from PDR and macular hole (MH) were measured by ELISA. The effects of EC-SOD on VEGF-induced proliferation, migration, and tube formation were evaluated using human umbilical vein endothelial cells (HUVECs). Moreover, the effects of EC-SOD on VEGF-induced proliferation and migration were evaluated in HUVECs and primary normal human retinal microvascular endothelial cells.
Results
Intravitreal concentrations of EC-SOD were significantly higher (p<0.01) in PDR (58.0±23.8 ng/ml, mean±SD) than in MH (29.3±6.6 ng/ml). Intravitreal concentrations of VEGF were dramatically higher (p<0.01) in PDR (798.2±882.7 pg/ml) than in MH (17.7±15.5 pg/ml). The serum concentrations of EC-SOD and VEGF did not differ between the two patient groups. The vitreous concentrations of VEGF correlated with those of EC-SOD in all patients (rs=0.61, p<0.001). In HUVECs, EC-SOD at 100 ng/ml significantly suppressed VEGF-induced proliferation and tube formation, but not VEGF-induced migration.
Conclusions
EC-SOD was increased together with VEGF in the vitreous body from PDR patients, suggesting that EC-SOD may play a pivotal role in the pathogenesis of angiogenesis.
PMCID: PMC2791042  PMID: 20011081

Results 1-6 (6)