Effects of Cudrania tricuspidata water extract on blood pressure and renal functions in NO-dependent hypertension

Plants Used as Antihypertensive

Hypertension is a critical health problem and worse other cardiovascular diseases. It is mainly of two types: Primary or essential hypertension and Secondary hypertension. Hypertension is the primary possibility feature for coronary heart disease, stroke and renal vascular disease. Herbal medicines have been used for millions of years for the management and treatment of hypertension with minimum side effects. Over aim to write this review is to collect information on the anti-hypertensive effects of natural herbs in animal studies and human involvement as well as to recapitulate the underlying mechanisms, from the bottom of cell culture and ex-vivo tissue data. According to WHO, natural herbs/shrubs are widely used in increasing order to treat almost all the ailments of the human body. Plants are the regular industrial units for the invention of chemical constituents, they used as immunity booster to enhance the natural capacity of the body to fight against different health problems as well as herbal medicines and food products also. Eighty percent population of the world (around 5.6 billion people) consume medicines from natural plants for major health concerns. This review provides a bird's eye analysis primarily on the traditional utilization, phytochemical constituents and pharmacological values of medicinal herbs used to normalize hypertension i.e. Hibiscus sabdariffa, Allium sativum, Andrographis paniculata, Apium graveolens, Bidenspilosa, Camellia sinensis, Coptis chinensis, Coriandrum sativum, Crataegus spp., Crocus sativus, Cymbopogon citrates, Nigella sativa, Panax ginseng,Salviaemiltiorrhizae, Zingiber officinale, Tribulus terrestris, Rauwolfiaserpentina, Terminalia arjuna etc.

Enantiomeric Isoflavones with neuroprotective activities from the Fruits of Maclura tricuspidata

Seven pairs of enantiomeric isoflavones (1a/1b–7a/7b) were obtained from the ethyl acetate extract of the fruits of Maclura tricuspidata (syn. Cudrania tricuspidata), and successfully separated by chiral high-pressure liquid chromatography (HPLC). The structures and absolute configurations of the enantiomeric isoflavones were established on the basic of comprehensive spectroscopic analyses and quantum chemical calculation methods. Compounds 1, 1a, and 1b exhibited neuroprotective activities against oxygen-glucose deprivation/reoxygenation (ODG/R)-induced SH-SY5Y cells death with EC₅₀ values of 5.5 µM, 4.0 µM, and 10.0 µM, respectively. Furthermore, 1, 1a, and 1b inhibited OGD/R-induced reactive oxygen species generation in SH-5Y5Y cells with IC₅₀ values of 6.9 µM, 4.5 µM, and 9.5 µM, respectively.

Optimization of Jirisan Mountain Cudrania tricuspidata leaf substance extraction across solvents and temperatures

Objective

The aim of this study is to optimize the extraction of beneficial substance from Cudrania tricuspidata leaves grown at Jirisan Mountain in South Korea by three different solvents depending on extraction time and at different temperature.

Methods

The total phenolic contents were determined by the method reported by Sánchez-Moreno et al. The total flavonoid contents were analyzed by Slinkard and Singleton. The DPPH radical scavenging activity was determined according to the method reported by Blois

Results

The extraction yield for each solvent is 9.05–14.1%, 2.17–5.67%, and 2.3–3.9% for D.W., ethanol, and hexane, respectively. The overall results were maximized for the extract obtained with D.W. for 5 min at 100°C. The average phenol contents were 77.11, 45.64, and 0.343 mg/g at 100°C in water, 78°C in ethanol, and 68°C in hexane, respectively. The flavonoid contents were the highest in the materials extracted with D.W., and were increased with increasing temperature, regardless of the extraction solvents, whether water (green), polar organic ethanol, or nonpolar organic hexane. In the ethanol extract, the flavonoid contents are increased gradually from 5.66 mg/g to 7.73 mg/g. The total flavonoid contents were proportional to the concentrations of the water extracts, ranging from 4.14 mg/g to 48.89 mg/g. The antioxidative activities of the water-extracted compounds are generally increased with increasing temperature from 42.5% to 85.5%. Those of the hexane extracts are increased slowly from 3.79% to 8.8%, while those of ethanol extracts are increased from 29.8% to 47.4%.

Conclusion

The extraction yields were dependent upon solvents for extraction as well as extraction time and the temperature. The optimal extraction time was 5 min and the extraction yields were increased with increasing temperature excepted hexane. Of the three tested extraction solvents, the greenest solvent of water shows excellent results, suggesting that water is among the most effective solvents for natural sample extractions for general medicinal, pharmaceutical, and food applications.

Effects of propolis, caffeic acid phenethyl ester, and pollen on renal injury in hypertensive rat: An experimental and theoretical approach

The objective of this study was to evaluate the antioxidant effects of propolis, caffeic acid phenethyl ester (CAPE; active compound in propolis), and pollen on biochemical oxidative stress biomarkers in rat kidney tissue inhibited by N^ω -nitro-L-arginine methyl ester (L-NAME). The biomarkers evaluated were paraoxonase (PON1), oxidative stress index (OSI), total antioxidant status (TAS), total oxidant status (TOS), asymmetric dimethylarginine (ADMA), and nuclear factor kappa B (NF-κB). TAS levels and PON1 activity were significantly decreased in kidney tissue samples in the L-NAME-treated group (P < 0.05). The levels of TAS and PONI were higher in the L-NAME plus propolis, CAPE, and pollen groups compared with the L-NAME-treated group. TOS, ADMA, and NF-κB levels were significantly increased in the kidney tissue samples of the L-NAME-treated group (P < 0.05). However, these parameters were significantly lower in the L-NAME plus propolis, CAPE, and pollen groups (P < 0.05) compared with rats administered L-NAME alone (P < 0.05). Furthermore, the binding energy of CAPE within catalytic domain of glutathione reductase (GR) enzyme as well as its inhibitory mechanism was determined using molecular modeling approaches. In conclusion, experimental and theoretical data suggested that oxidative alterations occurring in the kidney tissue of chronic hypertensive rats may be prevented via active compound of propolis, CAPE administration.

Cudrania tricuspidata: an updated review on ethnomedicine, phytochemistry and pharmacology

This review summarized the botany, traditional uses, phytochemistry and pharmacology ofCudrania tricuspidata, and the limitations of the studies on this species were also discussed so as to serve as the basis for further research and development of this medicinal plant.

Inhibition of Angiotensin Converting Enzyme, Angiotensin II Receptor Blocking, and Blood Pressure Lowering Bioactivity across Plant Families

Hypertension is a major risk factor for coronary heart disease, kidney disease, and stroke. Interest in medicinal or nutraceutical plant bioactives to reduce hypertension has increased dramatically. The main biological regulation of mammalian blood pressure is via the renin-angiotensin-aldosterone system. The key enzyme is angiotensin converting enzyme (ACE) that converts angiotensin I into the powerful vasoconstrictor, angiotensin II. Angiotensin II binds to its receptors (AT1) on smooth muscle cells of the arteriole vasculature causing vasoconstriction and elevation of blood pressure. This review focuses on the in vitro and in vivo reports of plant-derived extracts that inhibit ACE activity, block angiotensin II receptor binding and demonstrate hypotensive activity in animal or human studies. We describe 74 families of plants that exhibited significant ACE inhibitory activity and 16 plant families with potential AT1 receptor blocking activity, according to in vitro studies. From 43 plant families including some of those with in vitro bioactivity, the extracts from 73 plant species lowered blood pressure in various normotensive or hypertensive in vivo models by the oral route. Of these, 19 species from 15 families lowered human BP when administered orally. Some of the active plant extracts, isolated bioactives and BP-lowering mechanisms are discussed.

Cudrania tricuspidata Stem Extract Induces Apoptosis via the Extrinsic Pathway in SiHa Cervical Cancer Cells

The focus of this study is the anti-cancer effects of Cudrania tricuspidata stem (CTS) extract on cervical cancer cells. The effect of CTS on cell viability was investigated in HPV-positive cervical cancer cells and HaCaT human normal keratinocytes. CTS showed significant dose-dependent cytotoxic effects in cervical cancer cells. However, there was no cytotoxic effect of CTS on HaCaT keratinocytes at concentrations of 0.125-0.5 mg/mL. Based on this cytotoxic effect, we demonstrated that CTS induced apoptosis by down-regulating the E6 and E7 viral oncogenes. Apoptosis was detected by DAPI staining, annexin V-FITC/PI staining, cell cycle analysis, western blotting, RT-PCR, and JC-1 staining in SiHa cervical cancer cells. The mRNA expression levels of extrinsic pathway molecules such as Fas, death receptor 5 (DR5), and TNF-related apoptosis-inducing ligand (TRAIL) were increased by CTS. Furthermore, CTS treatment activated caspase-3/caspase-8 and cleavage of poly (ADP-ribose) polymerase (PARP). However, the mitochondrial membrane potential and expression levels of intrinsic pathway molecules such as Bcl-2, Bcl-xL, Bax, and cytochrome C were not modulated by CTS. Taken together, these results indicate that CTS induced apoptosis by activating the extrinsic pathway, but not the intrinsic pathway, in SiHa cervical cancer cells. These results suggest that CTS can be used as a modulating agent in cervical cancer.

HPLC Analysis, Antioxidant, Anti-inflammatory and Xanthine Oxidase Inhibitory Activity of Cudrania tricuspidata

Cudrania tricuspidata is a plant used in folk medicine in Korea for treatment of diseases related to oxidative stress and inflammation. In this study the leaf and shoot extract was studied for its antioxidant, anti-inflammatory, and xanthine oxidase (XO) inhibitory activities. The extract with predominant phenolics was quantified using HPLC-DAD. Antioxidant activity was measured using ABTS [2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) and FRAP (ferric ion reducing antioxidant power), and anti-inflammatory activity by diene-conjugate and β-glucuronidase assays. The average antioxidant effects of C. tricuspidata extracts (1–2 mg/mL) revealed significant activity of 32.5% to 50.2% (ABTS) and 24.2 to 40.5% (FRAP) compared with Trolox, having 55.1% (ABTS) and 42.6% (FRAP) activity, respectively. The anti-inflammatory activities showed as 26.5% to 40.5% (DC) and 40.2% to 70.2% (βG) inhibition compared with the control {phenylbutazone; 42.1% (DC) and 80.2% (βG) inhibition, respectively}. The XO inhibitory activity of the plant extract revealed 90.5% inhibition of that of the control (allopurinol) (97% inhibition at 100 μg/mL concentration). The kinetic parameters of XO inhibition revealed a noncompetitive type of inhibition, where, K m and V max of C. tricuspidata extracts (25 to 100 μg/mL) were 0.25 mM/mL and 0.040, 0.036, 0.032, and 0.030 (μg/min), while for the positive control K m and V max the values were 0.30 mM/mL and 0.045 (μg/min), respectively. Results suggest that C. tricuspidata can be exploited against diseases associated with free radical formation and xanthine oxidase activity.

Alkaloids in Erythrina by UPLC-ESI-MS and In Vivo Hypotensive Potential of Extractive Preparations

Erythrina species are used in popular medicine as sedative, anxiolytic, anti-inflammatory, and antihypertensive. In this work, we investigated the chemical composition of extracts obtained from leaves of E. falcata and E. crista-galli. The hypotensive potential of E. falcata and the mechanism of action were also studied. The extracts were obtained by maceration and infusion. The total content of phenolic compounds and flavonoids was estimated by spectrophotometric methods. The chemical constituents were studied performing a chromatographic analysis by UPLC-ESI-MS. For in vivo protocols, blood pressure and heart rate were measured by the invasive hemodynamic monitoring method. Different concentrations of extracts and drugs such as L-NAME, losartan, hexamethonium, and propranolol were administrated i.v. The results of total phenolic contents for E. falcata and E. crista-galli were 1.3193-1.4989 mgGAE/mL for maceration and 0.8771-0.9506 mgGAE/mL for infusion. In total flavonoids, the content was 7.7829-8.1976 mg RE/g for maceration and 9.3471-10.4765 RE mg/g for infusion. The chemical composition was based on alkaloids, suggesting the presence of erythristemine, 11β-methoxyglucoerysodine, erysothiopine, 11β-hydroxyerysodine-glucose, and 11-hydroxyerysotinone-rhamnoside. A potent dose-dependent hypotensive effect was observed for E. falcata, which may be related to the route of β-adrenergic receptors.

Inhibition of lipopolysaccharide-induced nitric oxide and prostaglandin E2 production by chloroform fraction of Cudrania tricuspidata in RAW 264.7 macrophages

BACKGROUND

Cudrania tricuspidata extract is an important traditional herbal remedy for tumors, inflammation, gastritis, and liver damage and is predominantly used in Korea, China, and Japan. However, the anti-inflammatory effects of the extract have not yet been conclusively proved.

METHODS

In this study, we investigated the effects of the CHCl3 fraction (CTC) of a methanol extract of C. tricuspidata on the lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in RAW 264.7 macrophage cells and mouse peritoneal macrophages, and the levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in RAW 264.7 macrophage cells.

RESULTS

We observed that the protein expression levels of inducible NO synthase and COX-2 enzymes were markedly inhibited by CTC in a concentration-dependent manner. In addition, CTC reduced the production of TNF-α, IL-1β, and IL-6 in the LPS-stimulated RAW 264.7 macrophage cells.

CONCLUSIONS

Our results show that the C. tricuspidata extract could modulate macrophage-mediated inflammatory functions such as the overproduction of cytokines, NO, and PGE2. The CTC was found to be the active fraction in this context.

Inhibitory Activities of Cudrania tricuspidata Leaves on Pancreatic Lipase In Vitro and Lipolysis In Vivo

To identify effective herb to treat obesity, we screened 115 herbal extracts for inhibition of porcine pancreatic lipase (triacylg-ycerol acylhydrolase, EC 3.1.1.3) activity in vitro. Of the extracts tested, Cudrania tricuspidata leaves exhibited the most pronounced inhibitory effect on lipase activity with an IC₅₀ value of 9.91 μg/mL. Antilipid absorption effects of C. tricuspidata leaves were examined in rats after oral administration of lipid emulsions containing 50 or 250 mg  C. tricuspidata/kg body weight. Plasma triacylglycerol levels 2 h after the oral administration of emulsions containing C. tricuspidata were significantly reduced compared to the untreated group (P < 0.05). These results suggest that C. tricuspidata leaves may be useful for the treatment of obesity.

Effect of Viscum articulatum Burm. (Loranthaceae) in Nω-nitro-L-arginine methyl ester induced hypertension and renal dysfunction

ETHNOPHARMACOLOGICAL RELEVANCE

Viscum articulatum Burm. is used traditionally in Chinese medicine for treating hypertension.

AIM OF THE STUDY

The present study was designed to evaluate the antihypertensive activity of the methanolic extract of Viscum articulatum (MVA) against N(ω)-nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats.

MATERIALS AND METHODS

Six groups of rats were investigated for 4 weeks as normal control, L-NAME (40 mg/kg/day), L-NAME+enalapril (15 mg/kg/day), L-NAME+L-arginine (100 mg/kg/day), L-NAME+MVA (200 mg/kg/day) and L-NAME+MVA (400 mg/kg/day) for four weeks. The systolic blood pressure (SBP) and heart rate (HR) were measured weekly throughout the experimental period. The urine electrolytes concentration, cardiac mass index, serum nitrate/nitrite (NO(x)) level, serum creatinine level and lipid profile were determined.

RESULTS

Treatment with MVA (200 and 400 mg/kg) or enalapril delayed the rise in SBP produced by administration of L-NAME. None of the treatments had a significant effect on the depression of the serum NO(x) level caused by L-NAME. The serum creatinine and total cholesterol concentrations were elevated upon administration of L-NAME, and this elevation was prevented by MVA co-administration. The urine volume and urine potassium ion level were depressed by L-NAME administration and this effect being inhibited in MVA and enalapril groups. There was no cardiac hypertrophy and HR change after 28 day of L-NAME administration.

CONCLUSION

We conclude that MVA may have an antihypertensive effect in the NO deficient type of hypertension, which may be attributed to its diuretic, nephroprotective and hypolipidemic actions.

Sub-acute effect of N(G)-nitro-l-arginine methyl-ester (L-NAME) on biochemical indices in rats: Protective effects of Kolaviron and extract of Curcuma longa L

BACKGROUND

Kolaviron (KV) (biflavonoid from Garcinia kola) and extract of Curcuma longa (CL) are frequently used in folk medicine for treatment of hypertension. One of their mechanisms of action is to enhance antioxidant properties in animals. N(G)- nitro- l- arginine methyl- ester (L- NAME) is L- arginine analogue, which by binding to Nitric Oxide Synthase (NOS) may induce hypertension partly due to increase in tissues oxidative stress.

OBJECTIVES

To investigate the effect of L- NAME on some biochemical indices and the possible protective effect of KV or CL.

MATERIALS AND METHODS

Four groups consisting of 6 rats each were used. One group served as control, second group received L- NAME (40 mg/kg/day). Third and fourth groups were treated with KV and CL, respectively and also received L- NAME. KV and CL were given at a dose of 200 mg/kg/day.

RESULTS

L- NAME caused a significant (P <0.05) increase in the levels of serum urea, creatine kinase and alanine aminotransferase relative to controls. L- NAME treated rats had markedly decreased hepatic catalase (CAT), superoxide dismutase (SOD), glutathione- S- transferase (GST) and reduced glutathione (GSH) levels. Precisely, L- NAME decreased CAT, SOD, GST and GSH by 48, 52, 76 and 40%, respectively. L- NAME intoxication significantly decreased (P <0.05) renal GSH and SOD levels. Also, L- NAME caused a significant (P <0.05) induction of lipid peroxidation (LPO) in the animals. Administration of KV or CL with L- NAME caused significant (P <0.05) inhibition of LPO and augments tissue antioxidant indices.

CONCLUSION

These results confirm the adverse effect of L- NAME on biochemical indices and, the ability of kolaviron or Curcuma longa to ameliorate the alterations.

The fruits of Cudrania tricuspidata suppress development of atopic dermatitis in NC/Nga mice

The fruits of Cudrania tricuspidata are a medicinal herb in Korea, known for its antiatherosclerotic and antiinflammatory effects. Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by the influx of lymphocytes into the dermis. Using an animal model of AD, we assessed whether C. tricuspidata suppresses the development of AD-like skin lesions. Cudrania tricuspidata was administered orally to NC/Nga mice with Dermatophagoides-farinae-induced AD-like lesions for 49 days. The effects of C. tricuspidata were assessed by measuring clinical symptoms, swelling of the skin on the back and ears, and plasma concentrations of mTARC (mouse thymus and activation regulated chemokine), histamine and immunoglobulin E (IgE). We found that C. tricuspidata (60 mg/kg/day) inhibited the development of AD-like skin lesions, reduced skin dermatitis scores and inhibited the histological changes induced by repeated application of D. farinae. In addition, C. tricuspidata inhibited the increases in plasma concentrations of mTARC, histamine and IgE induced by D. farinae. These findings indicate that C. tricuspidata inhibits the development of AD-like skin lesions induced by repeated applications of D. farinae in sensitized NC/Nga by suppressing plasma concentrations of mTARC, histamine and IgE.

Vascular relaxation induced by aqueous extract of Lespedeza cuneata via the NO-cGMP pathway

The aqueous extract of Lespedeza cuneata G. Don. (ALC) induced vasorelaxation of phenylephrine precontracted aorta in a dose-dependent manner. This effect disappeared in the absence of functional endothelium. Pretreatment of the aortic tissues with N(G)-nitro-L-arginine methyl ester (L-NAME), or 1H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin-1-one (ODQ) blocked ALC-induced vascular relaxation. Incubation of endothelium-intact thoracic aortic rings with ALC increased cGMP production. ALC-induced cGMP production was blocked by pretreatment with L-NAME or ODQ. ALC-induced vascular relaxation was also markedly attenuated by addition of verapamil or diltiazem, but was not blocked by pretreatment with indomethacine, glibenclamide, tetraethylammonium, atropine, or propranolol. The results suggest that ALC dilates vascular smooth muscle via endothelium-dependent NO-cGMP signaling.

Ethyl acetate fraction from Cudrania tricuspidata inhibits IL-1beta-stimulated osteoclast differentiation through downregulation of MAPKs, c-Fos and NFATc1

BACKGROUND/AIMS

The present study was performed to determine the effects of the ethyl acetate extract of Cudrania tricuspidata (EACT) on interleukin (IL)-1beta-stimulated receptor activator of NF-kappaB ligand (RANKL)-mediated osteoclast differentiation.

METHODS

Bone marrow cells were harvested from 6-week-old male imprinting control region mice, and the differentiation of osteoclasts from these cells was evaluated by tartrate-resistant acid phosphatase and resorption pit formation assay. Phosphorylated extracellular signal regulated kinase (p-ERK), phosphorylated p38, phosphorylated c-Jun amino-terminal kinase, NF-kappaB (p65), IkappaBalpha, c-Fos, and nuclear factor of activated T-cells c1 (NFATc1) expression was examined by immunoblotting and quantitative reverse transcription-polymerase chain reaction.

RESULTS

EACT inhibits IL-1beta-stimulated RANKL-mediated osteoclast differentiation. EACT also inhibits IL-1beta-stimulated RANKL-mediated phosphorylation of ERK 1/2, p38 mitogen activated protein kinase, and expression of c-Fos and NFATc1.

CONCLUSIONS

These results suggest that EACT may be involved in the inhibition of bone loss by preventing osteoclast formation and may be used to manage bone destruction in inflammatory diseases, such as rheumatoid arthritis.

Anti-inflammatory action of Cudrania tricuspidata on spleen cell and T lymphocyte proliferation

This study examined whether an extract of Cudrania tricuspidata shows anti-proliferative effects in anti-CD3/CD28-mediated spleen and CD4+CD25− T cells and decreases the production of the pro-inflammatory cytokines interleukin-2 (IL-2) and interferon-γ (IFN-γ) in anti-CD3/CD28-mediated CD4+CD25− T cells. The proliferation of anti-CD3/CD28-mediated spleen cells and CD4+CD25− T cells was effectively suppressed by C. tricuspidata. This extract, however, did not show cytotoxicity in spleen cells under conditions where the antigen was not stimulated using CCK-8 analysis. C. tricuspidata also decreased the production of the pro-inflammatory cytokines IL-2 and IFN-γ by selective inhibition of this extract on proliferating cells in anti-CD3/CD28-mediated CD4+CD25− T cells. These results suggest that C. tricuspidata may be useful in the treatment of autoimmune diseases and organ transplantation through the inhibitory action of T cells in inflammation.

Antioxidant activities of new flavonoids from Cudrania tricuspidata root bark

Two new flavonoids, hydroxybenzyl flavonoid glycosides (6-p-hydroxybenzyl kaempferol-7-O-beta-D-glucopyranoside named cudranian 1 and 6-p-hydroxybenzyl quercetin-7-O-beta-D-glucopyranoside named cudranian 2), and 3 known flavonoids (kaempferol-7-O-beta-D-glucopyranoside, quercetin-7-O-beta-D-glucopyranoside and aromadendrin) were isolated from root bark of Cudrania tricuspidata and their structures were elucidated by spectroscopic methods. These compounds showed remarkable radical scavenging effects against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and anti-lipid peroxidation efficacy on human low-density lipoprotein by TBARS assay.

Arbutus unedo prevents cardiovascular and morphological alterations in L-NAME-induced hypertensive rats Part I: cardiovascular and renal hemodynamic effects of Arbutus unedo in L-NAME-induced hypertensive rats

Hypertension induced by nitric oxide synthase inhibition is associated with functional abnormalities of the heart and kidney. The aim of the present study was to investigate whether chronic treatment with Arbutus unedo leaf (AuL) or root (AuR) aqueous extracts can prevent these alterations. Six groups of rats were used: control group received tap water; N(G)-nitro-l-arginine methyl-ester (L-NAME) group treated with L-NAME at 40 mg/kg/day; AuL and AuR groups received simultaneously L-NAME (40 mg/kg/day) and Au leaves or roots extract at the same concentration 250 mg/kg/day; l-arginine and enalapril groups received simultaneously L-NAME (40 mg/kg/day) and l-arginine at 50mg/kg/day or enalapril at 15 mg/kg/day. Treatment of rats during 4 weeks with L-NAME caused an increase of the systolic blood pressure (SBP) accompanied by a ventricular hypertrophy, an impairment of endothelium-dependent vasorelaxation, an increase of the cardiac baroreflex sensitivity and a decrease of water, sodium and potassium excretion. The co-administration of AuL or AuR extracts with L-NAME reduces the development of increased SBP, ameliorates the vascular reactivity as well as the baroreflex sensitivity and normalizes the renal function. AuR reduces the ventricular hypertrophy but AuL do not. Enalapril associated with L-NAME reverses the majority of alterations induced by L-NAME while l-arginine only lightly ameliorates the vascular reactivity. These results show that chronic treatment with Arbutus extract regress the development of hypertension and ameliorate cardiovascular and renal functions in NO deficient hypertension.

A novel water-soluble alpha-(1-->4)-glucan from the root of Cudrania tricuspidata

CTPS-01, a water-soluble polysaccharide, was obtained from the root of Cudrania tricuspidata and estimated to have an average molecular weight of 5.9 x 10(3) and to be composed of glucose residues, solely. It contains an average repeating unit of decasaccharide, having a backbone consisting of 1,4-linked alpha-D-glucopyranosyl residues, to which a side chain consisting of terminal and 1,4-linked alpha-D-glucopyranosyl residues is attached at position O-6 of the branching residues.

Anti-atherosclerotic and anti-inflammatory activities of catecholic xanthones and flavonoids isolated from Cudrania tricuspidata

The catecholic xanthones and flavonoids 1-13 were isolated from the root bark of Cudrania tricuspidata. Compounds 1 and 3-8 exhibited significant antioxidant activity against low-density lipoprotein (LDL) oxidation in the thiobarbituric acid-reactive substance (TBARS) assay. Among them, prenylated flavonoids 10-12 showed an inhibitory effect on the NO production and iNOS expression in RAW264.7 cells. Also, compounds 1, 2, 5, 7, 9, and 11 preferentially inhibited hACAT-2 than hACAT-1, whereas compounds 3, 4, 6, and 8 showed a similar specificity against hACAT-1 and -2. However, flavonoids 10, 12, and 13 dominantly inhibited hACAT-2, not hACAT-1.

Endothelium-dependent induction of vasorelaxation by the butanol extract of Phellinus igniarius in isolated rat aorta

The butanol extract of Phellinus igniarius (BPI) induced relaxation of the phenylephrin e-precontracted rat aorta in a dose-dependent manner, and its effect was abolished by the removal of functional endothelium. Pretreatment of the aortic tissues with N(G)-nitro-L-arginine methyl ester (L-NAME), methylene blue, or 1H-[1,2,4]-oxadiazole-[4,3-alpha]-quinoxalin1-one (ODQ) inhibited the vascular relaxation induced by BPI. BPI-induced vascular relaxations were also markedly attenuated by the addition of verapamil or diltiazem, while the relaxant effect of BPI was not blocked by pretreatment with indomethacine, glibenclamide, tetraethylammonium (TEA), atropine, or propranolol. Incubation of endothelium-intact rat aorta with BPI increased the production of cGMP in a dose-dependent manner. These results suggest that BPI dilates vascular smooth muscle via endothelium-dependent nitric oxide-cGMP signaling pathway, with the possible involvement of L-type Ca(2+) channels.

Vascular relaxation by the methanol extract of Sorbus cortex via NO-cGMP pathway

The methanol extract of Sorbus commixta cortex (MSC) induced relaxation of the phenylephrine-precontracted aorta in a dose-dependent manner, which was disappeared by removal of functional endothelium. Pretreatment of the aortic tissues with N(G)-nitro-L-arginine methyl ester (L-NAME), methylene blue, or 1H-[1,2,4]-oxadiazole-[4,3-alpha]-quinoxalin-1-one (ODQ) inhibited the vascular relaxation induced by MSC. MSC-induced vascular relaxations were also markedly attenuated by addition of verapamil or diltiazem, while the relaxant effect of MSC was not blocked by pretreatment with indomethacine, glibenclamide, tetraethylammonium (TEA), atropine, or propranolol, respectively. Incubation of endothelium-intact carotid arteries or of human umbilical vein endothelial cells (HUVECs) with MSC increased the production of guanosine 3',5'-cyclic monophosphate (cGMP). Moreover, MSC-induced cGMP production was effect was blocked by pretreatment with L-NAME or ODQ. These results suggest that MSC dilates vascular smooth muscle via endothelium-dependent nitric oxide-cGMP signaling pathway, possible involvement of L-type Ca(2+) channel.

Antioxidant and cytotoxic activities of xanthones from Cudrania tricuspidata

The new catecholic xanthone, 1,3,7-trihydroxy-4-(1,1-dimethyl-2-propenyl)-5,6-(2,2-dimethylchromeno)-xanthone (1), was isolated from the root bark of Cudrania tricuspidata together with seven known xanthones. The structures were fully characterized by analysis of physical and spectral (UV, IR, mass, and NMR) data. Relationships between the structural characteristics of xanthones and their antioxidant activities (DPPH, superoxide, and hydroxyl radical) were studied. Among the range of catecholic xanthones, 6,7-dihydroxyl xanthones (3-8) exhibited a strong scavenging effect on the DPPH radical. When one of the catecholic hydroxyl groups was protected as in compounds 1 and 2, DPPH radical scavenging activity was markedly decreased (IC(50)>200microM). DPPH activities were consistent with electrochemical response by cyclic voltammetry. Interestingly, compounds (1, 2) which had the weak activities on DPPH, exhibited both potent superoxide and hydroxyl radical scavenging activities. The strong activity on the hydroxyl radical of compounds (1, 2) could be rationalized by their chelating effect with iron (Fe(2+)) due to a redshift of its complex. The catecholic xanthones (3-8), being able to convert quinone methide intermediate, showed potent cytotoxicities against human cancer cell lines (HT-29, HL-60, SK-OV3, AGS, and A549). In particular, compounds 3, 6, and 7 had strong cytotoxic activities against AGS (LD(50)<5microM). DNA fragmentation patterns induced by catecholic xanthones revealed that tumor cell death was due to apoptosis.

Screening of vasorelaxant activity of some medicinal plants used in Oriental medicines

Hexane, ethylacetate (EtOAC), and n-butanol (n-BuOH) extracts of medicinal plants traditionally used in the East Asia, such as China, Korea, and Japan were screened for their vasorelaxant activity using isolated rat aorta. Among the 60 solvent-extracts from 20 medicinal plants, hexane and n-BuOH extracts of Diospyros kaki and Polygonum aviculare, hexane, EtOAC, and n-BuOH extracts of Magnolia liliflora, n-BuOH extract of Sorbus commixta, and EtOAC and n-BuOH extracts of Selaginella tamariscina were found to exhibit distinctive vasorelaxant activity. The activity disappeared by removal of functional endothelium or pre-treatment of the aortic tissues with N(G)-nitro-L-arginine methyl ester (L-NAME), which is an inhibitor of nitric oxide synthase. These findings suggest that the medicinal plants relax vascular smooth muscle via endothelium-dependent nitric oxide. These results will be useful to further analyze those medicinal plants that contain the vasorelaxant activity in order to identify the active principles.

Effects of bulbus Fritillaria water extract on blood pressure and renal functions in the L-NAME-induced hypertensive rats

A pharmacological inhibition of nitric oxide synthase (NOS) in rats produces renal vasoconstriction, renal dysfunction, and hypertension. The present study was aimed at investigating whether Bulbus Fritillaria water extract (BFWE) ameliorates NG-nitro-L-arginine methylester (L-NAME)-induced hypertension. Treatment of rats with L-NAME (60 mg/l drinking water, 4 weeks) caused a sustained increase in systolic blood pressure (SBP). The NO concentration in plasma and NO productions in the vascular tissues of the L-NAME-treated group were significantly reduced as compared with those in the control, whereas the expressions of NOS proteins were not altered. BFWE restored SBP to normal level in the L-NAME-treated hypertensive rats. Moreover, BFWE was able to preserve the vascular NO production and plasma NO metabolites concentration without changes of the expression NOS proteins. The renal functional parameters including urinary volume, sodium excretion, and creatinine clearance (Ccr) were significantly restored in rats co-treated with BFWE and L-NAME compared to the L-NAME-treated group. Taken together, these results suggest that BFWE prevents the increase of SBP in the L-NAME-induced hypertension that may have been caused by enhanced generation of vascular NO and amelioration of renal functions.

Green tea inhibits human inducible nitric-oxide synthase expression by down-regulating signal transducer and activator of transcription-1alpha activation

Green tea has been reported to show anti-inflammatory properties because of its inhibitory effects on the expression of several pro-inflammatory genes. Because the inducible nitricoxide synthase (iNOS) plays an important role in chronic inflammatory diseases, we have focused our attention on the regulation of iNOS expression by green tea in two different human epithelial cell lines, alveolar A549/8 and colon DLD-1 cells. With the use of electrophoretic mobility shift assays, we found a green tea-mediated down-regulation of the DNA binding activity of the transcription factor signal transducer and activator of transcription-1alpha (STAT-1alpha), but not of nuclear factor-kappaB. This down-regulation of the STAT-1alpha DNA binding was shown to result from reduced tyrosine phosphorylation of the STAT-1alpha protein and not from antioxidative effects of the green tea extract. Green tea extract inhibited human iNOS expression in a concentration-dependent manner, quantified in terms of iNOS mRNA, iNOS protein, and nitric oxide production in both cell lines. This inhibitory effect of green tea resulted from transcriptional inhibition as shown in reporter gene experiments. These data suggest that green tea extracts may be promising at least as an auxiliary anti-inflammatory principle in chronic inflammatory diseases.