Nitric oxide, human diseases and the herbal products that affect the nitric oxide signalling pathway

Planting the Seed for Blood Pressure Control: The Role of Plant-Based Nutrition in the Management of Hypertension

PURPOSE OF REVIEW

Hypertension results in significant morbidity, mortality, and healthcare expenditures. Fortunately, it is largely preventable and treatable by implementing dietary interventions, though these remain underutilized. Here, we aim to explore the role of healthy dietary patterns in hypertension management and describe approaches for busy clinicians to address nutrition effectively and efficiently with patients.

RECENT FINDINGS

DASH, Mediterranean, vegetarian, and vegan diets that include minimally processed, plant-based foods as core elements have consistently shown positive effects on hypertension. Recommendations that distill the most healthful components of these diets can significantly impact patient outcomes. Clinicians can harness evidence-based dietary assessment and counseling tools to implement and support behavioral changes, even during brief office visits. Healthful plant-based dietary patterns can often effectively prevent and treat hypertension. Clinicians may help improve patient outcomes by discussing evidence-based nutrition with their patients. Future work to promote infrastructural change that supports incorporating evidence-based nutrition into medical education, clinical care, and society at large can support these efforts.

A novel therapeutic effect of mannitol-rich extract from the brown seaweed Sargassum ilicifolium using in vitro and in vivo models

BACKGROUND

Wound healing is an active, complex, integrated series of cellular, physiological, and biochemical changes initiated by the stimulus of injury in a tissue. The present study was performed to investigate the potential wound healing abilities of Sargassum ilicifolium crude extracts (CE) that were characterized by 1H NMR and FTIR Spectrometric measurements.

MATERIALS AND METHODS

Seaweed samples were collected from southern coastal sites of Sri Lanka. To determine the cytotoxicity and proliferation of S. ilicifolium CE were used for the MTT and alamarBlue assays respectively. The scratch and exclusion wound models were used to HaCaT and HDF cells to assess the cell proliferation and migration. RAW 264.7 cells (macrophages) were used to evaluate Nitric Oxide (NO) production and phagocytosis activities. Moreover, Fifteen, 8-week-old, female, New Zealand rabbits were selected and divided into five groups: excision skin wounds (10.40 ± 0.60 mm) were induced in groups I, II, and III. Rabbits in groups I and IV were given S. ilicifolium CE (orally, 100 mg/kg day, two weeks), whereas groups II and V were given equal amounts of distilled water. Wound healing properties were measured and wound tissue samples were collated, formalin-fixed, wax-embedded, stained (Hematoxylin and Eosin; Van Gieson) and examined for the healing process.

RESULTS

Anti-inflammatory and wound healing activities were observed in RAW 264.7, HDF and HaCaT cells treated with S. ilicifolium aqueous extracts when compared to the control groups. S. ilicifolium extracts concentration 8 - 4 μg/μL, (P<0.05) had remarkable the highest proliferative and migratory effects on RAW 264.7, HDF and HaCaT cells when compared with the control. RAW 264.7 cell proliferation and/or migration were higher in S. ilicifolium extracts (4 μg/μL, 232.8 ± 10.07%) compared with the control (100 %). Scratch wound healing were remarkably enhanced in 24 h, 48 h (P<0.05) when treated with S. ilicifolium on HaCaT cells. Rabbits treated with the CE of S. ilicifolium showed a significantly increased wound healing activities (P<0.05) within three days with a close wound area of 57.21 ± 0.77 % compared with control group (26.63 ± 1.09 %). Histopathology, aspartate aminotransferase and alanine aminotransferase levels evidenced no toxic effects on seaweed treated groups. Histopathological results also revealed that the healing process was significantly faster in the rabbit groups which were as treated with CE of S. ilicifolium orally with the evidence of enhanced early granulation tissue (connective tissue and angiogenesis) and significant epithelization compared to the control.

CONCLUSIONS

Cell proliferation and migration are significantly faster when treated with S. ilicifolium aqueous extracts. Moreover, there are no toxic effect of S. ilicifolium aqueous extracts on RAW 264.7, HDF and HaCaT cell lines. In this study, it is revealed that S. ilicifolium has potential remedial agent; D-Mannitol for skin wound healing properties that by promote keratinocyte and fibroblast proliferation and migration. These findings show that S. ilicifolium have promising wound healing properties.

Cardiovascular characterization of the novel organic mononitrate NDIBP in rats

Organic nitrates are widely used to restore endogenous nitric oxide (NO) levels reduced by endothelial nitric oxide synthase dysfunction. However, these drugs are associated with undesirable side effects, including tolerance. This study aims to investigate the cardiovascular effects of the new organic nitrate 1,3-diisobutoxypropan-2-yl nitrate (NDIBP). Specifically, we assessed its effects on blood pressure, vascular reactivity, acute toxicity, and the ability to induce tolerance. In vitro and ex vivo techniques showed that NDIBP released NO both in a cell-free system and in isolated mesenteric arteries preparations through a process catalyzed by xanthine oxidoreductase. NDIBP also evoked endothelium-independent vasorelaxation, which was significantly attenuated by 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl 3-oxide (PTIO, 300 μM), a nitric oxide scavenger; 1-H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, 10 μM), a soluble guanylyl cyclase inhibitor; tetraethylammonium (TEA, 3 mM), a potassium channel blocker; febuxostat (500 nM), a xanthine oxidase inhibitor; and proadifen (10 μM), an inhibitor of cytochrome P450 enzyme. Furthermore, this organic nitrate did not induce tolerance in isolated vessels and presented low toxicity following acute oral administration. In vivo changes on cardiovascular parameters were assessed using normotensive and renovascular hypertensive rats. NDIBP evoked a reduction of blood pressure that was significantly higher in hypertensive animals. Our results suggest that NDIBP acts as a NO donor, inducing blood pressure reduction without having the undesirable effects of tolerance. Those effects seem to be mediated by activation of NO-sGC-cGMP pathway and positive modulation of K+ channels in vascular smooth muscle.

Near-infrared (NIR) fluorescence-emitting small organic molecules for cancer imaging and therapy

We discuss recent advances made in the development of NIR fluorescence-emitting small organic molecules for tumor imaging and therapy.

Comparative Study of the Antioxidant and Enzyme Inhibitory Activities of Two Types of Moroccan Euphorbia Entire Honey and Their Phenolic Extracts

Honey is a natural food product very famous for its health benefits for being an important source of antioxidant and phenolic compounds. Euphorbia honeys obtained from different regions of Morocco were evaluated for their ability to inhibit acetylcholinesterase, lipoxygenase, tyrosinase and xanthine oxidase activities. Their antioxidant properties were evaluated using the: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity, nitric oxide scavenging activity (NO) and scavenging ability of superoxide anion radical. Then, the phenolic extracts of the same entire honey samples were evaluated by liquid chromatography coupled to diode array detection and mass spectrometry (LC-DAD-MS) and tested for the biological activities previously evaluated on the entire honeys, in order to conduct a comparative study between both (honey and phenolic extracts). The chromatographic profiles for the studied Euphorbia honey extracts were different. Phenolic compounds gallic acid, 4-hydroxybenzoic acid and p-coumaric acid were detected in all samples, whereas kampferol was only present in two samples. Physicochemical parameters and total phenolic content were also determined. Entire honey that recorded the highest rate of phenols was sample M6 (E. resinifera) = 69.25 mg GAE/100 g. On the other hand, the phenolic extracts had better antioxidant and enzyme inhibitory activities than the entire honeys, regardless the monofloral honey type. In conclusion, the studied Euphorbia honeys may have a great potential as antioxidant, anti-inflammatory and anti-tyrosinase sources for pharmaceutical and cosmetic applications.

Quantification of Nicotine and Cotinine in Plasma, Saliva, and Urine by HPLC Method in Chewing Tobacco Users

BACKGROUND

Nicotine acts as major alkaloid of all tobacco products including smokeless tobacco (SLT) forms. The mode of SLT consumption is in the form of chewing under the cheek or lip and induced biochemical alterations in the plasma, saliva, and urine.

MATERIALS AND METHODS

The smokeless tobacco products like Raja or blue bull tobacco brands are widely consumed by human male volunteers under the age of 18-30 years for the period of 3 years consisting of 30g per day. The concentrations of nicotine and cotinine in samples of plasma, saliva, and urine are quantified by the method of HPLC. The remaining variables of plasma are evaluated by auto analyzer and spectrophotometric methods.

RESULTS

The analysis of results presented that significant increase in the levels of nicotine and cotinine in plasma, saliva, and urine of chewing tobacco users. The lipid profile (Cholesterol, triglycerides, HDL-C, and LDL-C), liver marker enzymes (SGOT, SGPT, and ALP), kidney markers (Creatinine, urea, and uric acid), glucose, and the remaining variables are present within normal range observed in SLT users. The lipid peroxidation (LPO), nitric oxide (NO) (NO2 and NO3), protein carbonyls (PCO), and peroxynitrites (ONOO-) are reported to be higher levels in the plasma of experimental subjects in comparison with normal controls. The various brands of tobacco varieties (Raja, madhu chhap, hans chhap, miraj, badshah, blue bull, and swagat gold tobacco) are presented.

CONCLUSION

The chewing tobacco users exhibited greater amounts of nicotine and cotinine are at risk of cardiovascular due to nicotine has cardiovascular effects, and oral cancer disease complications in the future for chronic consumption of smokeless tobacco products  due to the presence of carcinogens of tobacco-specific N-nitrosamines.

Evaluation of the cardioprotective effect of Casuarina suberosa extract in rats

The aim of the current study was to examine and compare the cardioprotective activities of the chloroform and petroleum extracts the leaves of Casuarina suberosa in isoproterenol (ISO)-induced cardiac tissue oxidative stress. Rats were categorized into 6 groups as follows: control group, vehicle or Tween 80-treated group, ISO-treated group, chloroform extract + ISO treated group, petroleum ether extract + ISO treated group and Reference drug (Captopril) + ISO treated group. ISO injection significantly (p < 0.05) increased the activities of cardiac marker enzymes (CK-MB, LDH, ALT, and AST), cardiac troponin-I, levels of lipid peroxides (MDA), nitric oxide (NO), and vascular endothelial growth factor (VEGF), serum angiotensin-converting enzyme (ACE) activity and neutrophil infiltration marker; myeloperoxidase (MPO) in the cardiac tissues. Pretreatment with chloroform or petroleum ether extracts significantly (p < 0.05) prevented the ISO-induced alteration; they upregulated VEGF expression. Histopathological findings corroborated biochemical results. These extracts exerted a cardioprotective effect by alleviating oxidative stress.

Herbal Dietary Supplements for Erectile Dysfunction: A Systematic Review and Meta-Analysis

PURPOSE

Erectile dysfunction (ED) is a common condition that significantly affects quality of life and interpersonal relationships.

OBJECTIVE

Our objective was to perform a systematic review and meta-analysis to evaluate the efficacy of herbal dietary supplements in the treatment of ED.

MATERIALS AND METHODS

We searched five databases to identify randomized controlled trials (RCTs) that evaluated the clinical efficacy of herbal medicines in ED. Quality was assessed and risk of bias was estimated using the Jadad score and the Cochrane risk-of-bias tool.

RESULTS

In total, 24 RCTs, including 2080 patients with ED, were identified. Among these, 12 evaluated monopreparations (five ginseng [n = 399], three saffron [n = 397], two Tribulus terrestris [n = 202], and one each Pinus pinaster [n = 21] and Lepidium meyenii [n = 50]), seven evaluated formulations (n = 544), and five investigated dietary supplements in combination with pure compounds (n = 410). Ginseng significantly improved erectile function (International Index of Erectile Function [IIEF]-5 score: 140 ginseng, 96 placebo; standardized mean difference [SMD] 0.43; 95% confidence interval [CI] 0.15-0.70; P < 0.01; I² = 0), P. pinaster and L. meyenii showed very preliminary positive results, and saffron and T. terrestris treatment produced mixed results. Several herbal formulations were associated with a decrease of IIEF-5 or IIEF-15, although the results were preliminary. The quality of the included studies varied, with only seven having a prevalent low risk of bias. The median methodological quality Jadad score was three out of a maximum of five. Adverse events were recorded in 19 of 24 trials, with no significant differences between placebo and verum in placebo-controlled studies.

CONCLUSIONS

Encouraging evidence suggests that ginseng may be an effective herbal treatment for ED. However, further, larger, and high-quality studies are required before firm conclusions can be drawn. Promising (although very preliminary) results have also been generated for some herbal formulations. Overall, more research in the field, adhering to the CONSORT statement extension for reporting trials, is justified before the use of herbal products in ED can be recommended.

The novel organic mononitrate NDHP attenuates hypertension and endothelial dysfunction in hypertensive rats

Rationale

Development and progression of cardiovascular diseases, including hypertension, are often associated with impaired nitric oxide synthase (NOS) function and nitric oxide (NO) deficiency. Current treatment strategies to restore NO bioavailability with organic nitrates are hampered by undesirable side effects and development of tolerance. In this study, we evaluated NO release capability and cardiovascular effects of the newly synthesized organic nitrate 1, 3-bis (hexyloxy) propan-2-yl nitrate (NDHP).

Methods

A combination of in vitro and in vivo approaches was utilized to assess acute effects of NDHP on NO release, vascular reactivity and blood pressure. The therapeutic value of chronic NDHP treatment was assessed in an experimental model of angiotensin II-induced hypertension in combination with NOS inhibition.

Results

NDHP mediates NO formation in both cell-free system and small resistance arteries, a process which is catalyzed by xanthine oxidoreductase. NDHP-induced vasorelaxation is endothelium independent and mediated by NO release and modulation of potassium channels. Reduction of blood pressure following acute intravenous infusion of NDHP was more pronounced in hypertensive rats (two-kidney-one-clip model) than in normotensive sham-operated rats. Toxicological tests did not reveal any harmful effects following treatment with high doses of NDHP. Finally, chronic treatment with NDHP significantly attenuated the development of hypertension and endothelial dysfunction in rats with chronic NOS inhibition and angiotensin II infusion.

Conclusion

Acute treatment with the novel organic nitrate NDHP increases NO formation, which is associated with vasorelaxation and a significant reduction of blood pressure in hypertensive animals. Chronic NDHP treatment attenuates the progression of hypertension and endothelial dysfunction, suggesting a potential for therapeutic applications in cardiovascular disease.

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The organic nitrate NDHP mediates NO formation in cell-free system and blood vessels.

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NDHP-mediated NO release is dependent on functional XOR.

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NDHP induces endothelium-independent vasorelaxation and significant reduction of blood pressure.

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NDHP-mediated vasorelaxation involves activation of NO/cGMP/PKG pathway and K⁺ channels (K_v and BK_Ca).

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Chronic treatment with NDHP attenuates the development of hypertension and endothelial dysfunction.

Role of the Red Ginseng in Defense against the Environmental Heat Stress in Sprague Dawley Rats

Global temperature change causes heat stress related disorders in humans. A constituent of red ginseng has been known the beneficial effect on the resistance to many diseases. However, the mechanism of red ginseng (RG) against heat stress still remains unclear. To determine the effect of RG on heat stress, we examined the effect of the RG on the gene expression profiles in rats subjected to environmental heat stress. We evaluated the transcripts associated with hepatic lipid accumulation and oxidative stress in rats subjected to heat stress. We also analyzed the reactive oxygen species (ROS) contents. Our results suggested RG inhibited heat stress mediated altering mRNA expressions include HSPA1, DEAF1, HMGCR, and FMO1. We also determined RG attenuated fat accumulation in the liver by altering C/EBPβ expression. RG promoted to repress the heat stress mediated hepatic cell death by inhibiting of Bcl-2 expression in rats subjected to heat stress. Moreover, RG administered group during heat stress dramatically decreased the malondialdehyde (MDA) contents and ROS associated genes compared with the control group. Thus, we suggest that RG might influence inhibitory effect on environmental heat stress induced abnormal conditions in humans.

Effects of natural mineral-rich water consumption on the expression of sirtuin 1 and angiogenic factors in the erectile tissue of rats with fructose-induced metabolic syndrome

Consuming a high-fructose diet induces metabolic syndrome (MS)-like features, including endothelial dysfunction. Erectile dysfunction is an early manifestation of endothelial dysfunction and systemic vascular disease. Because mineral deficiency intensifies the deleterious effects of fructose consumption and mineral ingestion is protective against MS, we aimed to characterize the effects of 8 weeks of natural mineral-rich water consumption on the structural organization and expression of vascular growth factors and receptors on the corpus cavernosum (CC) in 10% fructose-fed Sprague-Dawley rats (FRUCT). Differences were not observed in the organization of the CC either on the expression of vascular endothelial growth factor (VEGF) or the components of the angiopoietins/Tie2 system. However, opposing expression patterns were observed for VEGF receptors (an increase and a decrease for VEGFR1 and VEGFR2, respectively) in FRUCT animals, with these patterns being strengthened by mineral-rich water ingestion. Mineral-rich water ingestion (FRUCTMIN) increased the proportion of smooth muscle cells compared with FRUCT rats and induced an upregulatory tendency of sirtuin 1 expression compared with the control and FRUCT groups. Western blot results were consistent with the dual immunofluorescence evaluation. Plasma oxidized low-density lipoprotein and plasma testosterone levels were similar among the experimental groups, although a tendency for an increase in the former was observed in the FRUCTMIN group. The mineral-rich water-treated rats presented changes similar to those observed in rats treated with MS-protective polyphenol-rich beverages or subjected to energy restriction, which led us to hypothesize that the effects of mineral-rich water consumption may be more vast than those directly observed in this study.

Endothelium-Dependent Relaxation Effect of Apocynum venetum Leaf Extract via Src/PI3K/Akt Signalling Pathway

Botanical herbs are consumed globally not only as an essential diet but also as medicines or as functional/recreational food supplements. The extract of the Apocynum venetum leaves (AVLE), also known as Luobuma, exerts its antihypertensive effect via dilating the blood vessels in an endothelium- and concentration-dependent manner with optimal effect seen at as low as 10 µg/mL. A commercial Luoboma “antihypertensive tea” is available commercially in the western province of China. The present study seeks to investigate the underlying cellular mechanisms of the nitric oxide (NO)-releasing property of AVLE in rat aortas and human umbilical vein endothelial cells (HUVECs). Endothelium-dependent relaxation induced by AVLE was assessed in organ chambers in the presence or absence of polyethyleneglycol catalase (PP2, 20 µM; inhibitor of Src kinase), wortmannin (30 nM) and LY294002 (20 µM; PI3 (phosphatidylinositol3)-Kinase inhibitor), N^G-nitro-l-arginine (L-NAME, 100 µM; endothelial NO synthase inhibitor (eNOS)) and ODQ (1 µM; soluble guanylyl cyclase inhibitor). Total nitrite and nitrate (NOx) level and protein expression of p-Akt and p-eNOS were measured. AVLE-induced endothelium-dependent relaxation was reduced by PP2, wortmannin and LY294002 and abolished by L-NAME and ODQ. AVLE significantly increased total NO_x level in rat aortas and in HUVECs compared to control. It also instigated phosphorylation of Akt and eNOS in cultured HUVECs in a concentration-dependent manner and this was markedly suppressed by PP2, wortmannin and LY294002. AVLE also inhibited superoxide generated from both NADPH oxidase and xanthine/xanthine oxidase system. Taken together, AVLE causes endothelium-dependent NO mediated relaxations of rat aortas through Src/PI3K/Akt dependent NO signalling pathway and possesses superoxide scavenging activity.

Effect of Kaempferia parviflora Extract on Physical Fitness of Soccer Players: A Randomized Double-Blind Placebo-Controlled Trial

Background

Physical fitness is a fundamental prerequisite for soccer players. Kaempferia parviflora is an herbal plant that has been used in some Asian athletes with the belief that it might prevent fatigue and improve physical fitness. This study aimed to determine the effects of Kaempferia parviflora on the physical fitness of soccer players.

Material/Methods

Sixty soccer players who routinely trained at a sports school participated in a double-blind placebo-controlled trial and were randomly allocated to the treatment group or the placebo group. The participants in both groups were given either 180 mg of Kaempferia parviflora extract in capsules or a placebo once daily for 12 weeks. Baseline data were collected using the following 6 tests of physical performance: a sit-and-reach test, a hand grip strength test, a back-and-leg strength test, a 40-yard technical test, a 50-metre sprint test, and a cardiorespiratory fitness test. All of the tests were performed every 4 weeks throughout the 12-week study period.

Results

The study showed that after treatment with Kaempferia parviflora, the right-hand grip strength was significantly increased at weeks 4, 8, and 12. The left-hand grip strength was significantly increased at week 8. However, the back-and-leg strength, the 40-yard technical test, the sit-and-reach test, the 50-metre sprint test, and the cardiorespiratory fitness test results of the treatment group were not significantly different from those of the placebo group.

Conclusions

Taking Kaempferia parviflora supplements for 12 weeks may significantly enhance some physical fitness components in soccer players.

Recent trends of nano bioactive compounds from ginseng for its possible preventive role in chronic disease models

Bioactive nano ginseng has roles in various diseases.

Honey and cardiovascular risk factors, in normal individuals and in patients with diabetes mellitus or dyslipidemia

Diabetes mellitus, hypercholesteremia, hypertension (HTN), and obesity are well-known risk factors for cardiovascular diseases (CVD). Various medications are currently in use for management of these comorbidities. Undesirable side effects are unavoidable and the ultimate and ideal goal is hardly achieved. Honey and other bee products are widely used in traditional medicine for management of many diseases. Others and the authors have found potent biological activities of these products. Honey is now reintroduced in modern medicine as part of wound and burn management. Honey has antioxidant, anti-inflammatory, and antimicrobial activities. More studies are exploring other aspects of honey activity such as its effect on blood sugar, body weight, lipid profile, C-reactive protein, nitric oxide, proinflammatory prostaglandins, and homocysteine. Growing evidence and scientific data support the use of honey in patients with diabetes, HTN, dyslipidemia, obesity, and CVD. This review discusses clinical and preclinical studies on potential influence of honey on diabetes mellitus and cardiovascular risk factors, and emphasizes the importance of conducting more clinical and controlled studies.

A review on plants used for improvement of sexual performance and virility

The use of plant or plant-based products to stimulate sexual desire and to enhance performance and enjoyment is almost as old as the human race itself. The present paper reviews the active, natural principles, and crude extracts of plants, which have been useful in sexual disorders, have potential for improving sexual behaviour and performance, and are helpful in spermatogenesis and reproduction. Review of refereed journals and scientific literature available in electronic databases and traditional literature available in India was extensively performed. The work reviews correlation of the evidence with traditional claims, elucidation, and evaluation of a plausible concept governing the usage of plants as aphrodisiac in total. Phytoconstituents with known structures have been classified in appropriate chemical groups and the active crude extracts have been tabulated. Data on their pharmacological activity, mechanism of action, and toxicity are reported. The present review provides an overview of the herbs and their active molecule with claims for improvement of sexual behaviour. A number of herbal drugs have been validated for their effect on sexual behavior and fertility and can therefore serve as basis for the identification of new chemical leads useful in sexual and erectile dysfunction.

Induction of Nitric Oxide Synthase by Saponins of Heat-Processed Ginseng

Total saponin of heat-processed ginseng (TSHG) stimulated the production of nitric oxide (NO) in interferon-gamma (IFN-gamma)-primed macrophages through the increased expression of inducible nitric oxide synthase (iNOS). However, TSHG by itself had a very weak effect on the NO synthesis without IFN-gamma priming. The saponins of white ginseng inhibited the NO production in lipopolysaccharide (LPS)/IFN-gamma activated macrophages rather than the stimulation of NO production found in IFN-gamma primed macrophages. The NO production by TSHG-stimulated macrophages was inhibited by the NOS inhibitor (N(G)-monomethyl-L-arginine (L-NMMA)) and nuclear factor-kappaB inhibitor (pyrrolidine dithiocarbamate (PDTC)). TSHG showed different serum-dependence from LPS on the activation of IFN-gamma primed macrophages. This property of TSHG may explain the intensified anti-tumor properties of heat-processed ginseng through its immunostimulating activity.

Antifatigue and Antioxidant Activity of Alcoholic Extract from Saussurea involucrata

Fatigue is a noticeable and highly prevalent symptom in tense, industriously, and economically affluent modern society. Therefore, new antifatigue agents to smooth the fatigue feature are an energetic topic. The total ethanol extract (ESI) of Saussurea involucrata Kar et Kir., known as Tian-Shan snow lotus, was evaluated for antifatigue activity in ICR mice with mice forced swimming test and the determination of the contents of blood lactic acid and serum urea nitrogen. ESI (0.05, 0.15, 0.25 g/kg) was administered orally to mice for 4 weeks. The average swimming times to exhaustion of the ESI-treated ICR mice (0.15, 0.25 g/kg) were prolonged by 132% and 180% (p<0.001) with a lessening of fatigue compared with that of the control group. Analysis of biochemical parameters showed that levels of serum urea nitrogen and blood lactic acid of experimental groups were also decreased significantly (p<0.001) compared with that of the control group. The antioxidant activity of ESI was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay and the hydrogen peroxide-induced luminol chemiluminescence assay and the results indicated that ESI exerts DPPH scavenging ability and reducing power. These results provide scientific evidence that S. involucrata may have been potential as an antifatigue agent.

Assessment of eyebright (euphrasia officinalis L.) extract activity in relation to human corneal cells using in vitro tests

BACKGROUND

Euphrasia officinalis L. is an herb traditionally used in folk medicine, mainly in the treatment of eye disorders.

AIMS

The present study analyzed the activity of three extracts of E. officinalis L. (ethanol, ethyl acetate and heptane) on cultured human corneal epithelial cells (10.014 pRSV-T).

STUDY DESIGN

In vitro study.

METHODS

Toxicity, free radical scavenging activity and the immunomodulatory effects of the extracts were tested using the thiazolyl blue tetrazolium bromide (MTT) or Neutral Red, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ELISA tests, respectively. Moreover, nitric oxide levels and cytoskeleton architecture were analyzed after corneal cell incubation with the plant extracts.

RESULTS

We show that the biological effect depended on both the concentration and the extraction solvent used. Heptane extracts, distinct from those in ethanol and ethyl acetate, were toxic to 10.014 pRSV-T cells at low concentrations (25 μg/mL) and did not demonstrate free radical scavenging effects. All tested extracts decreased pro-inflammatory cytokine expression (IL-1β, IL-6 and TNF-α) and also anti-inflammatory IL-10 expression by human corneal cells when the extracts were added to the cell culture medium for 24 h.

CONCLUSION

In conclusion, we show that the promising effects of the application of E. officinalis L. preparations as a supplementary therapy for eye disorders are associated with the ethanol and ethyl acetate extracts, not the heptane extract.

Advanced glycation end-products: a common pathway in diabetes and age-related erectile dysfunction

Reactive derivatives of non-enzymatic glucose-protein condensation reactions integrate a heterogeneous group of irreversible adducts called advanced glycation end-products (AGEs). Numerous studies have investigated the role of the AGEs in cardiovascular system; however, its contribution to erectile dysfunction (ED) that is an early manifestation of cardiovascular disease has been less intensively investigated. This review summarizes the most recent advances concerning AGEs effects in the cavernous tissue of the penis and in ED onset, particularly on diabetes and aging, conditions that not only favor AGEs formation, but also increase risk of developing ED. The specific contribution of AGE on intra- and extracellular deposition of insoluble complexes, interference in activity of endothelial nitric oxide (NO) synthase, NO bioavailability, endothelial-dependent vasodilatation, as well as molecular pathways activated by receptor of AGEs are presented. Finally, the interventional actions that prevent AGEs formation, accumulation or activity in the cavernous tissue and that include nutritional pattern modulation, nutraceuticals, exercise, therapeutic strategies (statins, anti-diabetics, inhibitors of phosphodiesterase-5, anti-hypertensive drugs) and inhibitors of AGEs formation and crosslink breakers, are discussed. From this review, we conclude that despite the experiments conducted in animal models pointing to the AGE/RAGE axis as a potential interventional target with respect to ED associated with diabetes and aging, the clinical data have been very disappointing and, until now, did not provide evidence of benefits of treatments directed to AGE inactivation.

Cryptochrome in sponges: a key molecule linking photoreception with phototransduction

Sponges (phylum: Porifera) react to external light or mechanical signals with contractile or metabolic reactions and are devoid of any nervous or muscular system. Furthermore, elements of a photoreception/phototransduction system exist in those animals. Recently, a cryptochrome-based photoreceptor system has been discovered in the demosponge. The assumption that in sponges the siliceous skeleton acts as a substitution for the lack of a nervous system and allows light signals to be transmitted through its glass fiber network is supported by the findings that the first spicules are efficient light waveguides and the second sponges have the enzymatic machinery for the generation of light. Now, we have identified/cloned in Suberites domuncula two additional potential molecules of the sponge cryptochrome photoreception system, the guanine nucleotide-binding protein β subunit, related to β-transducin, and the nitric oxide synthase (NOS)-interacting protein. Cryptochrome and NOSIP are light-inducible genes. The studies show that the NOS inhibitor L-NMMA impairs both morphogenesis and motility of the cells. Finally, we report that the function of primmorphs to produce reactive nitrogen species can be abolished by a NOS inhibitor. We propose that the sponge cryptochrome-based photoreception system, through which photon signals are converted into radicals, is coupled to the NOS apparatus.

Biochemical effects of Solidago virgaurea extract on experimental cardiotoxicity

Cardiovascular diseases (CVDs) are the major health problem of advanced as well as developing countries of the world. The aim of the present study was to investigate the protective effect of the Solidago virgaurea extract on isoproterenol-induced cardiotoxicity in rats. The subcutaneous injection of isoproterenol (30 mg/kg) into rats twice at an interval of 24 h, for two consecutive days, led to a significant increase in serum lactate dehydrogenase, creatine phosphokinase, alanine transaminase, aspartate transaminase, and angiotensin-converting enzyme activities, total cholesterol, triglycerides, free serum fatty acid, cardiac tissue malondialdehyde (MDA), and nitric oxide levels and a significant decrease in levels of glutathione and superoxide dismutase in cardiac tissue as compared to the normal control group (P < 0.05). Pretreatment with S. virgaurea extract for 5 weeks at a dose of 250 mg/kg followed by isoproterenol injection significantly prevented the observed alterations. Captopril (50 mg/kg/day, given orally), an inhibitor of angiotensin-converting enzyme used as a standard cardioprotective drug, was used as a positive control in this study. The data of the present study suggest that S. virgaurea extract exerts its protective effect by decreasing MDA level and increasing the antioxidant status in isoproterenol-treated rats. The study emphasizes the beneficial action of S. virgaurea extract as a cardioprotective agent.

The lignan (-)-cubebin inhibits vascular contraction and induces relaxation via nitric oxide activation in isolated rat aorta

Cubebin, the most abundant lignan in Piper cubeba, has been described as having several effects as trypanocidal, antimycobacterial, antispasmodic, antimicrobial, anti-inflammatory, and analgesic. This study investigated the vasorelaxant effect produced by (-)-cubebin in isolated rat aortic rings pre-contracted with phenylephrine (Phe), and the possible mechanism involved in this event was evaluated. Endothelium-dependent relaxation was evoked by acetylcholine and (-)-cubebin in intact aortic rings, while endothelium-independent vasorelaxation was elicited by sodium nitroprusside and (-)-cubebin in denuded rings. Cumulative concentration-response curves for Phe (10(-10) -10(-5)  M) were determined for endothelium-intact and endothelium-denuded aortic rings in either the presence or absence of (-)-cubebin. Dose-response curves were also constructed for pre-incubation of vascular rings with Nω-nitro-L-arginine methyl ester (L-NAME) (a non-specific nitric oxide synthase inhibitor), indomethacin (an unspecific cyclooxygenase inhibitor), and 1H-[1,2,4] oxadiazolo [4,3-a]quinoxalin-1-one (ODQ) (a guanylyl cyclase inhibitor). (-)-Cubebin was found to exert a vasorelaxant effect irrespective of the presence of endothelium, which was abolished by pretreatment with L-NAME and ODQ, but not with indomethacin. In addition, (-)-cubebin was able to reduce Phe contraction in the case of intact rings. These results suggest that (-)-cubebin promotes vasorelaxation via NO/cGMP pathway in rat aorta, without prostacyclin involvement.

Apocynum venetum leaf extract, an antihypertensive herb, inhibits rat aortic contraction induced by angiotensin II: a nitric oxide and superoxide connection

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves extract of Apocynum venetum (AVLE), also known as "luobuma", have long been used in traditional Chinese medicine to treat hypertension and depression in parts of China and it has been shown to possess anti-oxidant and anti-lipid peroxidation effects. AVLE (10 μg/ml) has been reported to have a long-lasting endothelium-dependent relaxant effect and this effect has been proposed to be due to its nitric oxide(NO)-releasing and superoxide anion(SOA)-scavenging properties.

AIM OF THE STUDY

The present study seeks to evaluate the differential actions of AVLE extract between Ang II- and PE-induced vasoconstriction and the involvement of superoxide anions.

MATERIALS AND METHODS

Single dose of Ang II (100 nM and 1 nM)- or PE (0.1 μM)-induced contraction were assessed in both endothelium-intact and -denuded aortic rings after pre-incubation of AVLE (10 μg/ml) for 15 min. The experiment was repeated in either the presence of NO synthase inhibitor, L-NAME (300 μM) or selective AT(1) receptor inhibitor, losartan (0.1 nM), or superoxide scavenger, tiron (1 mM) or a combination of L-NAME and AVLE. Superoxide production was measured by using enhanced-chemiluminescence assay.

RESULTS

We have demonstrated that AVLE (10 μg/ml) effectively suppressed the Ang II-induced contraction (100 nM and 1 nM) of both endothelium-intact and -denuded rat aortic rings. In endothelium-intact rings, L-NAME, reversed AVLE-induced inhibition of Ang II-contraction. PE-induced contraction was significantly inhibited by AVLE in endothelium-intact rings, but not in endothelium-denuded rings. The inhibition by AVLE of PE-induced contraction was totally abolished in the presence of L-NAME. Ang II-induced SOA production concentration dependently with the optimal effect seen at 100 nM of Ang II, and AVLE (0.3, 1, 10 μg/ml) reduced this effect. SOA production in Ang II-stimulated rings was significantly higher than unstimulated control rings, while PE did not stimulate SOA production at all. SOA formation in the presence of Ang II was also inhibited in the presence of SOD (superoxide scavenger), DPI (NADPH inhibitor) and losartan (specific AT(1) receptor antagonist).

CONCLUSION

These results collectively suggest that the ability of AVLE in inhibiting Ang II-induced contraction via its SOA scavenging properties and nitric oxide releasing effect may account for its usage as an antihypertensive treatment in traditional folk medicine.

Mechanisms of the antinociceptive action of (-) epicatechin obtained from the hydroalcoholic fraction of Combretum leprosum Mart & Eic in rodents

BACKGROUND

The mechanisms of the antinociceptive activity of (-) epicatechin (EPI), a compound isolated from the hydroalcoholic fraction of Combreum leprosum Mart & Eicher.

METHODS

were assessed in the model of chemical nociception induced by glutamate (20 μmol/paw). To evaluate the mechanisms involved, the animals , male Swiss mice (25-30 g), received EPI (50 mg/kg p.o.) after pretreatment with naloxone (2 mg/kg s.c. opioid antagonist), glibenclamide (2 mg/kg s.c. antagonist K + channels sensitive to ATP), ketanserin (0.3 mg/kg s.c. antagonist of receptor 5-HT(2A)), yoimbine (0.15 mg/kg s.c. α2 adrenergic receptor antagonist), pindolol (1 mg/kg s.c. 5-HT1(a)/1(b) receptor antagonist), atropine (0.1 mg/kg s.c. muscarinic antagonist) and caffeine (3 mg/kg s.c. adenosine receptor antagonist), ondansetron (0.5 mg/kg s.c. for 5-HT(3) receptor) and L-arginine (600 mg/kg i.p.).

RESULTS

The antinociceptive effect of EPI was reversed by pretreatment with naloxone and glibenclamide, ketanserin, yoimbine, atropine and pindolol, which demonstrates the involvement of opioid receptors and potassium channels sensitive to ATP, the serotoninergic (receptor 5HT(1A) and 5HT(2A)), adrenergic (receptor alpha 2) and cholinergic (muscarinic receptor) systems in the activities that were observed. The effects of EPI, however, were not reversed by pretreatment with caffeine, L-arginine or ondansetron, which shows that there is no involvement of 5HT(3) receptors or the purinergic and nitrergic systems in the antinociceptive effect of EPI. In the Open Field and Rotarod test, EPI had no significant effect, which shows that there was no central nervous system depressant or muscle relaxant effect on the results.

CONCLUSIONS

This study demonstrates that the antinociceptive activity of EPI in the glutamate model involves the participation of the opioid system, serotonin, adrenergic and cholinergic.

Vasorelaxant action of the total alkaloid fraction obtained from Solanum paludosum Moric. (Solanaceae) involves NO/cGMP/PKG pathway and potassium channels

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum paludosum Moric. (jurubeba-roxa) is commonly used to treat hypertension as a substitute for Solanum paniculatum L. (jurubeba verdadeira). The total ethanolic extract from the root bark of Solanum paludosum have been found to cause hypotension in rats.

AIM OF THE STUDY

To investigate the mechanism by which the total alkaloid fraction obtained from the root bark of Solanum paludosum (FAT-SP) acts as a vasorelaxant agent on rat thoracic aorta.

MATERIALS AND METHODS

Rings of rat aorta were suspended in organ bath containing Krebs solution at 37°C, bubbled with carbogen mixture (95% O(2) and 5% CO(2)) under a resting tension of 1 g. Isometric contractions were measured using a force transducer coupled to an amplifier and a microcomputer.

RESULTS

FAT-SP has been found cause relaxation of the aortic rings pre-contracted with phenylephrine (Phe) in a concentration-dependent manner, in the presence and absence of endothelium. This effect was more potent on the endothelium-intact aorta. In the presence of endothelium, neither indomethacin (non-selective cyclooxygenase inhibitor) nor atropine (non-selective muscarinic receptor antagonist), produced significant changes on the relaxation response. On the other hand, in the presence of calmidazolium (a calmodulin inhibitor), N-nitro-L-arginine methyl ester (L-NAME, nitric oxide synthase inhibitor), hydroxocobalamin (HDX) (scavenger of free-radical nitric oxide), 1-H-[1,2,4]-oxadiazolo-[4,3a]-quinoxalin-1-one (ODQ, selective blocker of soluble guanylate cyclase), Rp-8-bromo-β-phenyl-1,N(2)-ethenoguanosine 3':5'-cyclic monophosphorothioate sodium salt hydrate (Rp-8-Br-PET-cGMPS, competitive inhibitor of cGMP-dependent protein kinase G) or TEA(+) (tetraethylammonium, nonselective potassium channel blocker), the vasorelaxant effect was significantly reduced, suggesting the involvement of NO/sCG/PKG pathway and potassium channel opening in vasorelaxant action of the FAT-SP.

CONCLUSION

The mechanism of vasorelaxant activity of the FAT-SP on rat aorta involves both NO/sCG/PKG pathway and potassium channels.

Therapeutic potential of ginseng in the management of cardiovascular disorders

Although employed in Asian societies for thousands of years, the use of ginseng as an herbal medication for a variety of disorders has increased tremendously worldwide in recent years. Ginseng belongs to the genus Panax, of which there exists a variety, generally reflecting their geographic origin. North American ginseng (Panax quinquefolius) and Asian ginseng (Panax ginseng) are two such varieties possessing a plethora of pharmacological properties, which are attributed primarily to the presence of different ginsenosides that bestow these ginsengs with distinct pharmacodynamic profiles. The many cardiovascular benefits attributed to ginseng include cardioprotection, antihypertensive effects, and attenuation of myocardial hypertrophy and heart failure. Experimental studies have revealed a number of beneficial properties of ginseng, particularly in the area of cardiac protection, where ginseng and ginsenosides have been shown to protect the ischaemic and reperfused heart in a variety of experimental models. Emerging evidence also suggests that ginseng attenuates myocardial hypertrophy, thus blunting the remodelling and heart failure processes. However, clinical evidence of efficacy is not convincing, likely owing primarily to the paucity of well designed, randomized, controlled clinical trials. Adding to the complexity in understanding the cardiovascular effects of ginseng is the fact that each of the different ginseng varieties possesses distinct cardiovascular properties, as a result of their respective ginsenoside composition, rendering it difficult to assign a general, common cardiovascular effect to ginseng. Additional challenges include the identification of mechanisms (likely multifaceted) that account for the effects of ginseng and determining which ginsenoside(s) mediate these cardiovascular properties. These concerns notwithstanding, the potential cardiovascular benefit of ginseng is worthy of further studies in view of its possible development as a cardiovascular therapeutic agent, particularly as adjunctive therapy to existing medications.

Rooibos (Aspalathus linearis) offers cardiac protection against ischaemia/reperfusion in the isolated perfused rat heart

Rooibos, a unique South African herbal tea, is known to be an important source of unique polyphenolic compounds. In the present study we have quantified the main polyphenolic compounds in both fermented/traditional and unfermented/"green" rooibos (Aspalathus linearis) and evaluated its cardioprotective effects against ischaemia/reperfusion injury. Male Wistar rats consumed aqueous rooibos and green tea (Camellia sinensis) extracts (2%, w/v) for 7 weeks before their hearts were rapidly excised and perfused in a working heart perfusion apparatus. The results showed that the rooibos supplemented hearts significantly improved aortic output recovery after reperfusion when compared to the green tea supplemented hearts. Additionally, we showed that the rooibos extracts, containing the highest amount of flavonols, significantly decreased the level of cleaved caspase-3 and PARP, both pro-apoptotic proteins, during reperfusion when compared to green tea. Green tea supplementation increased phosphorylation of total PKB/Akt, Akt (threonine 308) and Akt (serine 473). The rooibos extracts did not cause significant change in the levels of the pro-survival PKB/Akt (threonine 308 and serinet 473). The GSH/GSSG ratio in the hearts of the green tea supplemented group was significantly (p<0.05) lower when compared to RF (37.78±28.63), RU (33.20±4.13) and C (45.50±14.96). The results clearly demonstrate the cardio-protective properties of aqueous rooibos extracts via the inhibition of apoptosis which can possibly be related to the flavonol content of this unique South African herbal tea.

Prevention of rotavirus infections in vitro with aqueous extracts of Quillaja Saponaria Molina

BACKGROUND

Rotavirus is the leading cause of severe diarrhea disease in newborns and young children worldwide, estimated to be responsible for over 300,000 childhood deaths every year, mostly in developing countries. Rotavirus-related deaths represent approximately 5% of all deaths in children younger than 5 years of age worldwide. Saponins are readily soluble in water and are approved by the US FDA for inclusion in beverages intended for human consumption. The addition of saponins to existing water supplies offers a new form of intervention into the cycle of rotavirus infection. We believe that saponins will 'coat' the epithelium of the host's small intestine and prevent attachment of rotavirus.

DISCUSSION

This experiment provides in vitro data for the possibility of including saponin in drinking water to prevent infections of rotavirus. We demonstrate that microgram amounts of extract, while exhibiting no cell cytotoxicity or direct virucidal activity, prevent rotavirus from infecting its host cells. In addition, the presence of residual amounts of extract continue to block viral infection and render cells resistant to infection for at least 16 h after the removal of the extract from the cell culture media.

CONCLUSION

We demonstrate that two Quillaja extracts possess strong antiviral activity at concentrations more than 1000-fold lower than concentrations exhibiting cell cytotoxicity. Extract concentrations as high as 1000 μg/ml are not cytotoxic, but concentrations as low as 1.0 μg/ml are able to block rotavirus and reovirus attachment and infection.

Acute reduction of serum 8-iso-PGF2-alpha and advanced oxidation protein products in vivo by a polyphenol-rich beverage; a pilot clinical study with phytochemical and in vitro antioxidant characterization

Background

Measuring the effects of the acute intake of natural products on human biomarker concentrations, such as those related to oxidation and inflammation, can be an advantageous strategy for early clinical research on an ingredient or product.

Methods

31 total healthy subjects were randomized in a double-blinded, placebo-controlled, acute pilot study with post-hoc subgroup analysis on 20 of the subjects. The study examined the effects of a single dose of a polyphenol-rich beverage (PRB), commercially marketed as "SoZo^®", on serum anti-inflammatory and antioxidant markers. In addition, phytochemical analyses of PRB, and in vitro antioxidant capacity were also performed.

Results

At 1 hour post-intake, serum values for 8-iso-PGF2-alpha and advanced oxidation protein products decreased significantly by 40% and 39%, respectively. Additionally, there was a trend toward decreased C-reactive protein, and increased nitric oxide levels. Both placebo and PRB treatment resulted in statistically significant increases in hydroxyl radical antioxidant capacity (HORAC) compared to baseline; PRB showed a higher percent change (55-75% versus 23-74% in placebo group), but the two groups did not differ significantly from each other.

Conclusions

PRB produced statistically significant changes in several blood biomarkers related to antioxidant/anti-inflammatory effects. Future studies are justified to verify results and test for cumulative effects of repeated intakes of PRB. The study demonstrates the potential utility of acute biomarker measurements for evaluating antioxidant/anti-inflammatory effects of natural products.

Purification and characterization of a rhamnose-binding chinook salmon roe lectin with antiproliferative activity toward tumor cells and nitric oxide-inducing activity toward murine macrophages

In this study, a rhamnose-binding lectin from the roe of chinook salmon (Oncorhynchus tshawytscha) was purified and characterized, and its biological activities were examined in several model systems. Chinook salmon roe lectin had a molecular mass of 30 kDa and agglutinated rabbit and bovine erythrocytes. The hemagglutination activity of the lectin was not affected by metal ions. The lectin was stable up to 70 °C and between pH 4 and pH 11. Chinook salmon roe lectin did not exert antifungal activity toward the fungal species tested and did not exhibit mitogenic response toward mouse splenocytes up to a concentration of 5 mg/mL. The lectin had selective antiproliferative activity toward human breast cancer MCF-7 cells and hepatoma Hep G2 cells. It also induced the production of nitric oxide from mouse peritoneal macrophages. This is the first report that demonstrates these biological activities from chinook salmon roe lectin.

Reactive oxygen species-induced impairment of endothelium-dependent relaxations in rat aortic rings: protection by methanolic extracts of Phoebe grandis

Generation of reactive oxygen species plays a pivotal role in the development of cardiovascular diseases. The present study describes the effects of the methanolic extract of Phoebe grandis (MPG) stem bark on reactive oxygen species-induced endothelial dysfunction in vitro. Endothelium-dependent (acetylcholine, ACh) and -independent relaxation (sodium nitroprusside, SNP) was investigated from isolated rat aorta of Sprague-Dawley (SD) in the presence of the β-NADH (enzymatic superoxide inducer) and MPG extract. Superoxide anion production in aortic vessels was measured by lucigen chemiluminesence. Thirty minutes incubation of the rat aorta in vitro with β-NADH increased superoxide radical production and significantly inhibited ACh-induced relaxations. Pretreatment with MPG (0.5, 5 and 50 μg/mL) restored the ACh-induced relaxations (R_max: 92.29% ± 2.93, 91.02% ± 4.54 and 88.31 ± 2.36, respectively) in the presence of β-NADH. MPG was ineffective in reversing the impaired ACh-induced relaxations caused by pyrogallol, a non-enzymatic superoxide generator. Superoxide dismutase (a superoxide scavenger), however, reversed the impaired ACh relaxations induced by both β-NADH and pyrogallol. MPG also markedly inhibited the β-NADH-induced generation of the superoxide radicals. Furthermore, MPG scavenging peroxyl radicals generated by tBuOOH (10⁻⁴ M).These results indicate that MPG may improve the endothelium dependent relaxations to ACh through its scavenging activity as well as by inhibiting the NADH/NADPH oxidase induced generation of superoxide anions.

The effect of tannins on Mediterranean ruminant ingestive behavior: the role of the oral cavity

Sheep, cattle and goat are domestic ruminants of significant economic interest in the Mediterranean region. Although sharing the same pasture ranges, they ingest different plants and plant parts and, consequently different levels of tannins. This suggests an ability to detect and adapt ingestion according to animal physiological limits of tolerance for plant secondary metabolites. This review will detail the effects of dietary tannins on feeding behavior, and the role of the oral cavity in this process, with focus on such ruminant species. The role of salivary protein profile in tannin perception in the oral cavity, and as a defense mechanism, will be discussed.

No effect of acute ingestion of Thai ginseng (Kaempferia parviflora) on sprint and endurance exercise performance in humans

Thai ginseng, Kaempferia parviflora, is widely believed among the Mong hill tribe to reduce perceived effort and improve physical work capacity. Kaempferia parviflora is consumed before their daily work. Therefore, we conducted an acute study on the effects of K. parviflora on repeated bouts of sprint exercise and on endurance exercise time to exhaustion. Two studies were conducted in college males using a randomized, double-blind, crossover design. Ninety minutes after consumption of K. parviflora or a starch placebo, participants in study 1 (n = 19) completed three consecutive maximum 30-s sprint cycling Wingate tests, separated by 3 min recovery, while participants in study 2 (n = 16) performed submaximal cycling exercise to exhaustion. Peak and mean power output decreased with successive Wingate tests, while percent fatigue and blood lactate concentration increased after the third Wingate test (P < 0.05). There were no detectable differences in any measures with or without K. parviflora. There was also no effect of K. parviflora on time to exhaustion, rating of perceived exertion or heart rate during submaximal exercise. Our results indicate that acute ingestion of K. parviflora failed to improve exercise performance during repeated sprint exercise or submaximal exercise to exhaustion. However, chronic effects or actions in other populations cannot be excluded.

Anti-inflammatory activity of Alchornea triplinervia ethyl acetate fraction: inhibition of H₂O₂, NO and TNF-α

CONTEXT

Alchornea triplinervia (Spreng.) Müll. Arg. (Euphorbiaceae) is a tree widespread in many Brazilian states. This plant naturally occurs in different ecosystems including tropical Atlantic forest, Amazon rain forest, moist tropical mixed forest, savanna forest, among others. Local populations traditionally use it in tea form to treat gastric disturbances.

OBJECTIVE

The objective of this research was to evaluate the plant A. triplinervia as a potential inhibitor of some macrophage functions involved in the inflammatory process.

MATERIALS AND METHODS

The effects of Alchornea triplinervia ethyl acetate fraction (AtF) on hydrogen peroxide (H₂O₂), nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production in peritoneal macrophages were investigated using phenol red, Griess reagent and a sandwich immunoassay, respectively.

RESULTS

AtF chromatographic analyses indicate the presence of flavonoids as majority compounds. The fraction also showed an intense inhibition of H₂O₂ and NO production. The inhibitory effects of the fraction in H₂O₂ and NO production ranged from 72.25 ± 4.68 to 69.64 ± 4.21 and from 47.8 ± 8.96 to 76.77 ± 8.11%, respectively in the two tested concentrations, 15.62 and 62.5 μg/mL. TNF-α production was partially inhibited in the tested concentrations and the inhibitory rate was around 18%.

DISCUSSION AND CONCLUSION

It is supposed that the elevated biological potential of A. triplinervia is related to the presence of phenolic compounds in the plant leaves. According to the results observed in this study, it is suggested that AtF presents anti-inflammatory activity, supporting the traditional use of A. triplinervia in Brazilian folk medicine.

Traditional herbal remedies that influence cell adhesion molecule activity

Many traditional medicines have demonstrated immune activity, however, research has largely neglected their effects on cell adhesion molecules (CAMs). This review reports on extracts from 37 medicinal plant species, similar to or replicating traditional preparations, that up- or downregulate either gene or protein activity of CAMs. The majority of the investigations were in vitro, primarily of the immunoglobulin superfamily of CAMs, specifically intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and secondarily on the integrin (CD11b or MAC-1) and selectin (E-selectin and P-selectin) families of CAMs. The following plant species have demonstrated modulation of multiple CAMs: Artemisia asiatica, Boswellia serrata, Canscora decussata, Cinnamomum povectum, Dehaasia incrassate, Ganoderma lucidum, Ginkgo biloba, Hypericum perforatum, Juglans regia, Lycopus lucidus, Panax notoginseng, Rheum undulatum, Salvia miltiorrhiza. Many other species have documented activity on one CAM. Currently there are limited in vivo/ex vivo investigations, including a clinical trial on Mahonia aquifolium. Although further evidence is needed, the data suggest that the reviewed botanical medicines may have the potential to provide therapeutic potential in disease processes involving CAMs. Additionally, the reported success of many of these plant extracts by traditional cultures and modern phytotherapists may involve the modulation of CAMs.

Activation of nitric oxide/cGMP/PKG signaling cascade mediates antihypertensive effects of Muntingia calabura in anesthetized spontaneously hypertensive rats

We previously reported that the leaf extract of Muntingia calabura L. (Tiliaceae) exerts a potent hypotensive effect in the normotensive rats. The antihypertensive activity of this plant extract, however, is currently unknown. In the present study, we investigated the antihypertensive effects of the n-butanol soluble fraction (BSF) from methanol leaf extract of M. calabura in spontaneously hypertensive rats (SHR), and delineated is underlying mechanisms. The intravenous bolus administration of the BSF (10-100 mg/kg) of M. calabura produced biphasic dose-related antihypertensive and bradycardiac effects in SHR. The BSF-induced initial cardiovascular depressive effects lasted for 10 min, and the delayed effects commenced 40 min and lasted for at least 120 min postinjection. These cardiovascular depressive effects of BSF treatments were greater in SHR than in normotensive Wistar-Kyoto (WKY) rats. Both the initial and delayed antihypertensive and bradycardiac effects of BSF (25 mg/kg, i.v.) in SHR, were significantly blocked by pretreatment with a nonselective nitric oxide (NO) synthase (NOS) inhibitor, a soluble guanylyl cyclase (sGC) inhibitor, or a protein kinase G (PKG) inhibitor. Moreover, the initial effects of BSF in SHR were inhibited by pretreatment with a selective endothelial NOS (eNOS) inhibitor; whereas the delayed effects were attenuated by a selective inducible NOS (iNOS) inhibitor. These results indicate that the BSF from the leaf of M. calabura elicited both transient and delayed antihypertensive and bradycardiac actions in SHR, which might be mediated through NO generated respectively by eNOS and iNOS. Furthermore, activation of sGC/cGMP/PKG signaling pathway may participate in the M. calabura-induced biphasic cardiovascular effects.

Activation of nitric oxide signaling pathway mediates hypotensive effect of Muntingia calabura L. (Tiliaceae) leaf extract

The cardiovascular effect of the crude methanol extract from the leaf of Muntingia calabura L. (Tiliaceae) was investigated in the anesthetized rats. The crude methanol extract was sequentially fractionated to obtain the water-soluble extract (WSE). Intravenous administration of the WSE (10, 25, 50, 75 or 100 mg/kg) produced an initial followed by a delayed decrease in systemic arterial pressure (SAP) in a dose-dependent manner. The M. calabura-induced initial hypotension lasted for 10 min and the delayed depressor effect commenced after 90 min and lasted for at least 180 min post-injection. The same treatment, on the other hand, had no appreciable effect on heart rate (HR) or the blood gas/electrolytes concentrations. Both the initial and delayed hypotensive effects of WSE (50 mg/kg, i.v.) were significantly blocked by pre-treatment with a nonselective nitric oxide (NO) synthase (NOS) inhibitor, N(G)-nitro-L-arginine methyl ester ((L)-NAME, 0.325 mg/kg/min for 5 min) or a soluble guanylate cyclase (sGC) inhibitor, 1H-[1,2,4]oxadiazole[4,3-alpha]quinoxalin-1-one (ODQ, 0.2 mg/kg/min for 5 min). Moreover, whereas the initial depressor effect of WSE was inhibited by pre-treatment with a selective endothelial NOS (eNOS) inhibitor, N5-(1-Iminoethyl)-L-ornithine ((L)-NIO, 1 mg/kg/min for 5 min), the delayed hypotension was attenuated by a selective inducible NOS (iNOS) inhibitor, S-methylisothiourea (SMT, 0.5 mg/kg/min for 5 min). Administration of WSE also produced an elevation in plasma nitrate/nitrite concentration, as well as an increase in the expression of iNOS protein in the heart and thoracic aorta. These results indicate that WSE from the leaf of M. calabura elicited both a transient and delayed hypotensive effect via the production of NO. Furthermore, activation of NO/sGC/cGMP signaling pathway may mediate the M. calabura-induced hypotension.

Biological and medicinal properties of grapes and their bioactive constituents: an update

The grape is one of the most valued conventional fruits, worldwide. Although most of the parts of the grapevine are useful, primarily, the grape is considered as a source of unique natural products not only for the development of valuable medicines against a number of diseases, but also for manufacturing various industrial products. Over the last few decades, apart from the chemistry of grape compounds, considerable progress has been made towards exploring the biological activities of various grape-derived constituents. Today, it is well established that in addition to serving as food, the grape is a major source of several phytochemicals. The main biologically active and well-characterized constituent from the grape is resveratrol, which is known for various medicinal properties in human diseases. This review discusses the roles of various grape-derived phytochemicals in relation to various diseases.

The lignan eudesmin extracted from Piper truncatum induced vascular relaxation via activation of endothelial histamine H1 receptors

In Brazilian folk medicine, extracts from Piper species are used to reduce blood pressure. Previously, we demonstrated the vasodilatory activity of crude extracts from leaves of Piper truncatum explaining their possible use in the treatment of hypertension in traditional medicine. In the present study, we investigated the effects of eudesmin, a lignan isolated from hexane extract of leaves from Piper truncatum, on the contractility of rat aortas and the possible mechanisms involved in its vascular action. Eudesmin induced an intense concentration-dependent relaxation of aortic rings precontracted with phenylephrine. The concentration of eudesmin necessary to reduce phenylephrine-induced aortic contraction by 50% (IC(50)) was 10.69+/-0.67 microg/ml. Eudesmin-induced vasodilation required an intact endothelium since vascular relaxation was inhibited by mechanic removal of endothelium, and by pretreatment with nitric oxide synthase inhibitor and soluble guanylate cyclase inhibitor. Relaxation induced by eudesmin was also impaired in the presence of indomethacin and diphenhydramine, a cyclooxygenase inhibitor and an antagonist of type 1 histamine receptor (H(1)), respectively. IC(50) was increased to 18.1+/-1.8 and 18.1+/-2.6 microg/ml (P<0.05; n=6) after exposure to indomethacin and diphenhydramine, respectively. Atropine (muscarinic receptor antagonist), propranolol (beta-adrenoceptor antagonist) and glibenclamide (ATP-sensitive K(+) channel blocker) did not alter the effect of eudesmin. These results indicate that eudesmin-induced vascular relaxation in rat aorta is mediated by release of nitric oxide and prostanoid through the involvement of histamine receptor present in the endothelial cells.

Mechanisms of flavonoid protection against myocardial ischemia-reperfusion injury

Flavonoids have long been acknowledged for their unique antioxidant properties, and possess other activities that may be relevant to heart ischemia-reperfusion. They may prevent production of oxidants (e.g. by inhibition of xanthine oxidase and chelation of transition metals), inhibit oxidants from attacking cellular targets (e.g. by electron donation and scavenging activities), block propagation of oxidative reactions (by chain-breaking antioxidant activity), and reinforce cellular antioxidant capacity (through sparing effects on other antioxidants and inducing expression of endogenous antioxidants). Flavonoids also possess anti-inflammatory and anti-platelet aggregation effects through inhibiting relevant enzymes and signaling pathways, resulting ultimately in lower oxidant production and better re-establishment of blood in the ischemic zone. Finally, flavonoids are vasodilatory through a variety of mechanisms, one of which is likely interaction with ion channels. These multifaceted activities of flavonoids raise their utility as possible therapeutic interventions to ameliorate ischemia-reperfusion injury.