Antiplatelet effects and vasorelaxing action of some constituents of Formosan plants

Role of emodin in atherosclerosis and other cardiovascular diseases: Pharmacological effects, mechanisms, and potential therapeutic target as a phytochemical

The morbidity and mortality of cardiovascular diseases (CVDs) are increasing in recent years, and atherosclerosis (AS), a major CVD, becomes a disorder that afflicts human beings severely, especially the elders. AS is recognized as the primary cause and pathological basis of some other CVDs. The active constituents of Chinese herbal medicines have garnered increasing interest in recent researches owing to their influence on AS and other CVDs. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a naturally occurring anthraquinone derivative found in some Chinese herbal medicines such as Rhei radix et rhizome, Polygoni cuspidati rhizoma et radix and Polygoni multiflori root. In this paper, we first review the latest researches about emodin's pharmacology, metabolism and toxicity. Meanwhile, it has been shown to be effective in treating CVDs caused by AS in dozens of previous studies. Therefore, we systematically reviewed the mechanisms by which emodin treats AS. In summary, these mechanisms include anti-inflammatory activity, lipid metabolism regulation, anti-oxidative stress, anti-apoptosis and vascular protection. The mechanisms of emodin in other CVDs are also discussed, such as vasodilation, inhibition of myocardial fibrosis, inhibition of cardiac valve calcification and antiviral properties. We have further summarized the potential clinical applications of emodin. Through this review, we hope to provide guidance for clinical and preclinical drug development.

A Comprehensive Literature Review on Cardioprotective Effects of Bioactive Compounds Present in Fruits of Aristotelia chilensis Stuntz (Maqui)

Some fruits and vegetables, rich in bioactive compounds such as polyphenols, flavonoids, and anthocyanins, may inhibit platelet activation pathways and therefore reduce the risk of suffering from CVD when consumed regularly. Aristotelia chilensis Stuntz (Maqui) is a shrub or tree native to Chile with outstanding antioxidant activity, associated with its high content in anthocyanins, polyphenols, and flavonoids. Previous studies reveal different pharmacological properties for this berry, but its cardioprotective potential has been little studied. Despite having an abundant composition, and being rich in bioactive products with an antiplatelet role, there are few studies linking this berry with antiplatelet activity. This review summarizes and discusses relevant information on the cardioprotective potential of Maqui, based on its composition of bioactive compounds, mainly as a nutraceutical antiplatelet agent. Articles published between 2000 and 2022 in the following bibliographic databases were selected: PubMed, ScienceDirect, and Google Scholar. Our search revealed that Maqui is a promising cardiovascular target since extracts from this berry have direct effects on the reduction in cardiovascular risk factors (glucose index, obesity, diabetes, among others). Although studies on antiplatelet activity in this fruit are recent, its rich chemical composition clearly shows that the presence of chemical compounds (anthocyanins, flavonoids, phenolic acids, among others) with high antiplatelet potential can provide this berry with antiplatelet properties. These bioactive compounds have antiplatelet effects with multiple targets in the platelet, particularly, they have been related to the inhibition of thromboxane, thrombin, ADP, and GPVI receptors, or through the pathways by which these receptors stimulate platelet aggregation. Detailed studies are needed to clarify this gap in the literature, as well as to specifically evaluate the mechanism of action of Maqui extracts, due to the presence of phenolic compounds.

Role of Phaseolus vulgaris L. in the Prevention of Cardiovascular Diseases-Cardioprotective Potential of Bioactive Compounds

In terms of safe and healthy food, beans play a relevant role. This crop belongs to the species of Phaseolusvulgaris L., being the most consumed legume worldwide, both for poor and developed countries, the latter seek to direct their diet to healthy feeding, mainly low in fat. Phaseolus vulgaris L. stands out in this area-an important source of protein, vitamins, essential minerals, soluble fiber, starch, phytochemicals, and low in fat from foods. This species has been attributed many beneficial properties for health; it has effects on the circulatory system, immune system, digestive system, among others. It has been suggested that Phaseolus vulgaris L. has a relevant role in the prevention of cardiovascular events, the main cause of mortality and morbidity worldwide. Conversely, the decrease in the consumption of this legume has been related to an increase in the prevalence of cardiovascular diseases. This review will allow us to relate the nutritional level of this species with cardiovascular events, based on the correlation of the main bioactive compounds and their role as cardiovascular protectors, in addition to revealing the main mechanisms that explain the cardioprotective effects regulated by the bioactive components.

Emodin - A natural anthraquinone derivative with diverse pharmacological activities

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural anthraquinone derivative that is present in numerous globally renowned herbal medicines. It is recognised as a protein tyrosine kinase inhibitor and as an anticancer drug, active against various tumour cells, including lung, breast, liver, and ovarian cancer cells. Recently, its role in combination chemotherapy with various allopathic medicines, to minimize their toxicity and to enhance their efficacy, has been studied. The use of emodin in these therapies is gaining popularity, due to fewer associated side effects compared with standard anticancer drugs. Emodin has a broad therapeutic window, and in addition to its antineoplastic activity, it displays anti-ulcer, anti-inflammatory, hepatoprotective, neuroprotective, antimicrobial, muscle relaxant, immunosuppressive and antifibrotic activities, in both in vitro and in vivo models. Although reviews on the anticancer activity of emodin have been published, none coherently unite all the pharmacological properties of emodin, particularly the anti-oxidant, antimicrobial, antidiabetic, immunosuppressive and hepatoprotective activities of the compound. Hence, in this review, all of the available data regarding the pharmacological properties of emodin are explored, with particular emphasis on the modes of action of the molecule. In addition, the manuscript details the occurrence, biosynthesis and chemical synthesis of the compound, as well as its toxic effects on biotic systems.

Rutin: A Potential Antiviral for Repurposing as a SARS-CoV-2 Main Protease (Mpro) Inhibitor

Various computational studies, including in silico ones, have identified several existing compounds that could serve as effective inhibitors of the SARS-CoV-2 main protease (Mpro), and thus preventing replication of the virus. Among these, rutin has been identified as a potential hit, having prominent binding affinity to the virus. Moreover, its presence in several traditional antiviral medicines prescribed in China to infected patients with mild to moderate symptoms of COVID-19 justify its promise as a repurposed bioactive secondary metabolite against SARS-CoV-2.

Bilberry (Vaccinium myrtillus L.) Extracts Comparative Analysis Regarding Their Phytonutrient Profiles, Antioxidant Capacity along with the In Vivo Rescue Effects Tested on a Drosophila melanogaster High-Sugar Diet Model

Bilberries (Vaccinium myrtillus L.) have been reported to hold a plentitude of health-promoting properties beyond basic nutrition, mainly attributed to their anthocyanin content and antioxidant activity. In this article, we built the phytochemical profile of three wild bilberry fruit extract formulations (aqueous, methanolic, and hydro-methanolic) using UHPLC-ESI-MS/MS putative analysis, identifying 88 individual phytochemicals, mainly flavonoids (total content 8.41 ± 0.11 mg QE/g dw), free amino acids, polyphenols (total content 21.68 ± 0.19 mg GAE/g dw), carboxylic acids, and vitamins. Furthermore, the antioxidant activity of the extract was assessed, reaching 78.03 ± 0.16% DPPH free radical scavenging activity, comparable to literature values determined for bilberry extracts of other origin. Due to the increased prevalence of metabolic syndrome and based on the reviewed benefits of bilberries, we tested the most potent formulation of our bilberry extracts in this biological context. The in vivo rescue effect of a bilberry extract supplemented diet on Drosophila melanogaster was assessed by monitoring biochemical and genomic markers. Hemolymph trehalose levels were halved upon addition of 3% hydro-methanolic bilberry extract to a high-sugar (1.5 M sucrose) diet, as compared to the non-supplemented high-sugar diet. Noteworthy, the rescue seen for flies kept on the bilberry extract supplemented high-sugar diet appeared to parallel the trehalose levels observed in the case of the control diet (50 mM sucrose) flies. Moreover, next to the trehalose-lowering type of in vivo effects, other gene expression related rescues were also detected for genes such as InR, Akh, AstA, AstC, Irk, Npc2g, and CCHa2 upon supplementation of the high-sugar diet with our hydro-methanolic bilberry fruit extract. Our findings suggest that such a bilberry fruit extract could generate physiological and genomic type of compensatory mechanisms so that further translational approaches would advance the understanding of some human specific pathological conditions.

Emodin in atherosclerosis prevention: Pharmacological actions and therapeutic potential

Atherosclerotic plaque formation, destabilization and eventual rupture leads to the acute cardiovascular events including myocardial infarction and stroke. Emodin (PubChem CID#3220), (1,3,8-trihydroxy-6-methylanthracene-9,10-dione) is a pharmacologically bioactive constituent isolated from the traditional Chinese medicinal herb Radix rhizoma Rhei. This molecule has anti-oxidant, anti-inflammatory, anti-proliferative, anti-apoptotic and lipid-modulating effects. Experimental studies have demonstrated that emodin attenuates and stabilizes atherosclerotic plaques. In this mini-review, we provide a summary of the pharmacological actions of emodin in regulating vascular function and atherosclerosis, highlighting the therapeutic potential of this phytochemical in patients with cardiovascular disease.

Physiological relevance of food antioxidants

Dietary antioxidants are associated with prevention of oxidative stress related chronic diseases including certain types of cancer, cardiovascular diseases, diabetes, and neurodegenerative diseases. In recent years, there has been a growing interest in extending the knowledge on their physiological effects in human body. There are numbers of epidemiological, clinical, meta-analysis, and in vitro studies to explain formation mechanisms of each chronic diseases as well as the potential effects of dietary antioxidants on these diseases and gut health. Comprehensive studies for food antioxidants' journey from dietary intake to target tissues/organs deserve a serious consideration to have a clear understanding on the physiological effects of dietary antioxidants. Therefore, absorption and metabolism of dietary antioxidants, and the factors affecting their absorption, such as solubility of antioxidants, food matrix, and interaction between antioxidants have been evaluated in several research articles. This chapter provides an overview about potential health effects of dietary antioxidants considering with their absorption and metabolism in human body.

The granulopoietic cytokine granulocyte colony-stimulating factor (G-CSF) induces pain: analgesia by rutin

Rutin is a glycone form of the flavonol quercetin and it reduces inflammatory pain in animal models. Therapy with granulocyte colony-stimulating factor (G-CSF) is known by the pain caused as its main side effect. The effect of rutin and its mechanisms of action were evaluated in a model of hyperalgesia induced by G-CSF in mice. The mechanical hyperalgesia induced by G-CSF was reduced by treatment with rutin in a dose-dependent manner. Treatment with both rutin + morphine or rutin + indomethacin, at doses that are ineffectual per se, significantly reduced the pain caused by G-CSF. The nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG)-ATP-sensitive potassium channel (K_ATP) signaling pathway activation is one of the analgesic mechanisms of rutin. Rutin also reduced the pro-hyperalgesic and increased anti-hyperalgesic cytokine production induced by G-CSF. Furthermore, rutin inhibited the activation of the nuclear factor kappa-light-chain enhancer of activated B cells (NFκB), which might explain the inhibition of the cytokine production. Treatment with rutin upregulated the decreased mRNA expression of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) combined with enhancement of the mRNA expression of the Nrf2 downstream target heme oxygenase (HO-1). Intraperitoneal (i.p.) treatment with rutin did not alter the mobilization of neutrophils induced by G-CSF. The analgesia by rutin can be explained by: NO-cGMP-PKG-K_ATP channel signaling activation, inhibition of NFκB and triggering the Nrf2/HO-1 pathway. The present study demonstrates rutin as a promising pharmacological approach to treat the pain induced by G-CSF without impairing its primary therapeutic benefit of mobilizing hematopoietic progenitor cells into the blood.

Grape phytochemicals and associated health benefits

The phytochemicals present in fruits and vegetables may play an important role in deceasing chronic disease risk. Grapes, one of the most popular and widely cultivated and consumed fruits in the world, are rich in phytochemicals. Epidemiological evidence has linked the consumption of grapes with reduced risk of chronic diseases, including certain types of cancer and cardiovascular disease. In vitro and in vivo studies have shown that grapes have strong antioxidant activity, inhibiting cancer cell proliferation and suppressing platelet aggregation, while also lowering cholesterol. Grapes contain a variety of phytochemicals, like phenolic acids, stilbenes, anthocyanins, and proanthocyanidins, all of which are strong antioxidants. The phytochemical composition of grapes, however, varies greatly among different varieties. While extensive research exists, a literature review of the health benefits of grapes and their phytochemicals has not been compiled to summarize this work. The aim of this paper is to critically review the most recent literature regarding the concentrations, biological activities, and mechanisms of grape phytochemicals.

Inhibitory Effect of the Plant Clusia fluminensis against Biological Activities of Bothrops jararaca Snake Venom

The ability of extracts of the plant Clusia fluminensis Planch & Triana (Clusiaceae Lindl.) to neutralize proteolysis, clotting, hemolysis, hemorrhagic and lethality activities of Bothrops jararaca snake venom was studied. Clusianone and lanosterol from the flower and fruit extracts, respectively, were also tested. The extracts of different organs of C. fluminensis inhibited proteolysis and hemolysis induced by B. jararaca venom, but with different potencies. Only the stems prevented blood clotting. Only the acetone extract of the fruit protected mice from hemorrhage while the acetone or methanol extracts prevented mice from death. Clusianone and lanosterol did not inhibit clotting or hemorrhage, but the former inhibited proteolysis and the latter hemolysis.

Identification of kazinol Q, a natural product from Formosan plants, as an inhibitor of DNA methyltransferase

DNA methylation plays a pivotal role in the epigenetic regulation of the transcription of a number of cancer-related genes, thereby representing an important target for cancer prevention and treatment. In our search for DNA methyltransferase (DNMT) inhibitors from Formosan plants, by screening against a library consisting of 12 structurally distinct natural products, we identified kazinol Q {4-[6-(1,1-dimethyl-allyl)-7-hydroxy-chroman-2-yl]-3,6-bis-(3-methyl-but-2-enyl)-benzene-1,2-diol} as an inhibitor of recombinant DNMT1 with IC50 of 7 μM. The effect of kazinol Q on DNMT inhibition was validated by its ability to reactivate the expression of a DNA methylation-silenced gene, E-cadherin, in MDA-MB-231 breast cancer cells. Moreover, kazinol Q suppressed the proliferation of MCF-7 breast and LNCaP prostate cancer cells, in part, through apoptosis induction. The role of DNMT1 inhibition in mediating kazinol Q's antiproliferative effect was supported by the protective effect of ectopic expression of DNMT1 on kazinol Q-induced cell death. Molecular modeling analysis suggests that kazinol Q inhibited DNMT activity by competing with cytosine binding, a mechanism similar to that described for (-)-epigallocatechin-3-gallate (EGCG). Relative to EGCG, kazinol Q exhibits several desirable features for drug development, including chemical stability and increased hydrophobicity, and might have therapeutic relevance to cancer treatment.

Chrysophanol-8-O-glucoside, an anthraquinone derivative in rhubarb, has antiplatelet and anticoagulant activities

Rhubarb is a widely used traditional medicine and has been reported to elicit a number of biological effects including anti-inflammatory and antiplatelet effects. In the present study, we investigated the effects of anthraquinone derivatives isolated from rhubarb on platelet activity. Of four anthraquinone derivatives isolated from rhubarb examined, chrysophanol-8-O-glucoside (CP-8-O-glc) was found to have the most potent inhibitory effect on collagen- and thrombin-induced platelet aggregation. CP-8-O-glc-treated mice showed significantly prolonged bleeding times. Furthermore, CP-8-O-glc was found to have a significant inhibitory effect on rat platelet aggregation ex vivo and on thromboxane A(2) formation in vitro. In coagulation tests, CP-8-O-glc did not alter prothrombin time, and it prolonged the activated partial thromboplastin time. However, CP-8-O-glc only inhibited platelet phosphatidylserine exposure, but not exert direct inhibition on intrinsic factors. This study demonstrates the antiplatelet and anticoagulant effects of CP-8-O-glc and suggests that this compound might be of therapeutic benefit for the prevention of platelet-related cardiovascular diseases.

Dose response effect of rutin a dietary antioxidant on alcohol-induced prooxidant and antioxidant imbalance - a histopathologic study

The present study was designed to investigate the effect of rutin on ethanol-induced hepatotoxicity in a dose-dependent manner in rats. Male albino rats were divided into six groups. Group 1 rats served as control and group 2 rats received rutin 100 mg/kg body weight. Hepatotoxicity was induced in groups 3-6 rats (20% ethanol) for 60 days. In addition, groups 4-6 rats received rutin at doses of 25, 50, 100 mg/kg body weight, respectively for the last 30 days of the experiment. We observed a significant increase in the activities of liver marker enzymes, serum amino transferases, alkaline phosphatase, γ-glutamyl transpeptidase the levels of thiobarbituric acid reactive substances, conjugated dienes, lipid hydroperoxides, and a decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione and its related enzymes, vitamins C and E when compared to ethanol-fed rats. Rutin supplementation along with ethanol significantly decreased the levels of liver marker enzymes, lipid peroxidation and significantly elevated the activities of liver SOD, CAT, GSH, glutathione peroxidase, vitamins C and E when compared to untreated ethanol supplemented rats. Among the three doses, 100 mg/kg body weight of rutin was found to exert a more pronounced hepatoprotective effect against ethanol-induced toxicity. Our results were also confirmed by the histopathologic observations.

Kaempferol protects ischemia/reperfusion-induced cardiac damage through the regulation of endoplasmic reticulum stress

This study examined whether or not the ER stress and Bcl-2 proteins are linked to the protective effect of kaempferol, a phytoestrogen, on ischemia-reperfusion (I/R)-induced cardiac damage. In order to determine if kaempferol modifies the I/R-induced response in H9c2 cardiac muscle cells, the cells were exposed to kaempferol followed by ischemia 12h/reperfusion 4h. kaempferol had a protective effect on the apoptosis induced by I/R in the cardiac muscle cells. The Kaempferol treatment significantly increased the expression level of the anti-apoptotic protein, Bcl-2, but decreased the level of the pro-apoptotic protein, bax. Kaempferol down-regulated the expressions of the endoplasmic reticulum (ER) stress proteins, GRP78, ATF-6alpha, XBP-2, IRE1-alpha, phosphor-eIF-2alpha and CHOP. In ex vivo-Langendorff experiment, the kaempferol treatment regulated the expression of ER stress proteins-CHOP and GRP78. The kaempferol also improved the post-ischemic LVEDP and LVDP significantly after 20, 30, 40 and 50 min of reperfusion compared with the untreated control hearts, which shows that kaempferol offers protection against I/R-associated cardiac dysfunction.

Platelet Aggregation Inhibitors from Aerial Parts of Ruta Chalepensis Grown in Jordan

From the aerial parts of Ruta chalepensis L., grown in Jordan, two furanocoumarins (bergapten and chalepensin), one flavonoid glycoside (rutin) as well as several minor compounds have been isolated. The structural elucidation of these compounds was established based on spectral data (UV, IR, MS, 1 H-NMR and 13 C-NMR). In Jordan, R. chalepensis is recommended for the treatment of rheumatism, mental disorders and menstrual problems. Fresh and dried leaves are used as flavoring agent in food and beverages. Antiplatelet activities of the crude methanolic and ethylacetate extracts in addition to the three isolated major compounds were measured by the aggrometric method according to Beretz and Casenave. Optical aggregometer connected to dual channel recorder was used for measuring aggregation. Both, ethylacetate and methanol extracts inhibited ADP- induced platelet aggregation (ADP-IA) of human blood. However, only ethylacetate extract was able to induce 50% inhibition of collagen-induced platelet aggregation (Co-IA) platelet rich plasma. Bergapten was more active against ADP-IA compared to chalepensin while the latter was more active against Co-IA compared to bergapten.

Combined antioxidant effects of rutin and vitamin C in Triton X-100 micelles

UV-vis spectra, fluorescence emission spectra and cyclic voltammetric measurements were used to study the influence of Vitamin C on the antioxidant of rutin in Triton X-100 micelles. Rutin can be located in Triton X-100 micelles spontaneously through hydrophobic force, and the binding constant K between rutin and Triton X-100 increases with the rutin concentration. The embedment of two hydroxyl groups on rutin into the more hydrophobic micellar microenvironment makes the oxidation of rutin harder and the radical scavenging activity decrease. With low concentration of Vitamin C, the antioxidant capacity of rutin against hydroxyl radical is enhanced, while that capacity is partly inhibited when the concentration of Vitamin C become higher.

Astonishing diversity of natural surfactants: 5. Biologically active glycosides of aromatic metabolites

This review article presents 342 aromatic glycosides, isolated from and identified in plants and microorganisms, that demonstrate different biological activities. They are of great interest, especially for the medicinal and/or pharmaceutical industries. These biologically active natural surfactants are good prospects for the future chemical preparation of compounds useful as antioxidant, anticancer, antimicrobial, and antibacterial agents. These glycosidic compounds have been classified into several groups, including simple aromatic compounds, stilbenes, phenylethanoids, phenylpropanoids, naphthalene derivatives, and anthracene derivatives.

Synthesis, and Cytotoxic and Antiplatelet Activities of Oxime- and Methyloxime-Containing Flavone, Isoflavone, and Xanthone Derivatives

A series of oxime- and methyloxime-containing flavone, isoflavone, and xanthone derivatives (1-12) were synthesized (Scheme) and evaluated for their cytotoxic (Table 1) and antiplatelet activities (Table 2). The in vitro anticancer assay indicated that the cytotoxicity of structurally related compounds decreases in the order isoflavones (7a-7c) > flavones (8a-8c) > xanthones (9a-9c), electron-releasing substituents (R) on the Ph ring being favorable (mean GI50 values of 2.84, 12.3, and 20.9 microM for 7c, 8c, and 9c, resp.). The inhibition of platelet aggregation induced by arachidonic acid (AA) similarly decreased from the isoflavone 1 (IC50 = 2.97 microM) to the flavone 2 (7.70 microM) to the xanthone 3 (inactive). Thereby, compound 1 seems to be a promising lead, since it was not only the most-potent aggregation inhibitor (IC50 = 2.97 microM), but was also found to be noncytotoxic at a concentration of 100 microM.

Antiprotozoal effect of crude extracts and flavonoids isolated from Chromolaena hirsuta (asteraceae)

Phytochemical study of Chromolaena hirsuta (Hook. & Arn.) R. King & H. Robinson crude extract (collected in Furnas, MG-Brasil) produced fifteen flavonoids, two triterpenes and five steroids. IR, UV,(1)H and (13)C NMR spectroscopy and GC analysis were used for the identification of these compounds. The dichloromethanic and ethanolic crude extracts (flowers and leaves) and six flavonoids isolated from this specie have been assayed for antiprotozoal activity against tripomastigote forms of Trypanosoma cruzi and promastigote forms of Leishmania amazonensis. The crude extracts significantly reduced the viability of T. cruzi and Leishmania amazonensis, and the six flavonoids showed considerable antiproliferative effect of development of two parasites evaluated. This is the fi rst report of antiprotozoal activity of extracts of C. hirsuta.

The effect of vegetarian diet, plant foods, and phytochemicals on hemostasis and thrombosis

Ischemic heart disease (IHD) is multifactorial with a complex etiology. Conventional risk factors including serum lipids account for less than one half of future IHD events. In the past few years, novel risk factors such as hemostatic and thrombotic factors contributing to the development and progression of IHD have been explored. Typically, diet is the first line of consideration in the prevention of IHD, but very little is known about the effect of diet and nutrients on hemostasis and thrombosis. Cross-sectional studies indicate that vegetarians may have a lower concentration of certain markers of hemostasis compared with nonvegetarians. Platelet aggregation, an index of thrombosis, appears to be higher among vegetarians than nonvegetarians, perhaps because of the lower intake of long-chain n-3 fatty acids among vegetarians. Monounsaturated-fat-rich plant foods may have a protective role in hemostasis and may explain in part the lower incidence of IHD in Mediterranean countries where residents consume a diet high in monounsaturated fatty acid. Finally, certain fruits and vegetables such as soy, garlic, and purple grapes may have antithrombotic effects, which may in part be due to the phytochemicals in these foods. Although this review suggests that a plant-based diet with sufficient n-3 fatty acids and certain fruits and vegetables may have a favorable impact on hemostasis and thrombosis, the evidence is neither sufficient nor conclusive at this time to warrant specific recommendations for the public. Clearly, much remains to be done in this area of investigation.

Inhibitory effects of total flavones of Hippophae Rhamnoides L on thrombosis in mouse femoral artery and in vitro platelet aggregation

Total flavones of Hippophae Rhamnoides L (TFH) are extracted from Sea buckthorn, a Chinese herbal medicine. Sea buckthorn has antioxidant, anti-ulcerogenic and hepato-protective actions, and its berry oil is reported to suppress platelet aggregation. Though it is frequently used for patients with thrombosis, the likely mechanism(s) and effects of TFH on thrombogenesis remain unclear. Thus, we have investigated the effect in-vivo of TFH on thrombogenesis and in vitro on platelet aggregation, comparing them to those of aspirin. We measured thrombotic occlusion time in a mouse femoral artery thrombosis model by the photochemical reaction between intravenously injected rose bengal and green light irradiation. In vitro platelet aggregation in whole blood was measured by single platelet counting. Thrombotic occlusion time was 8.5 +/- 0.6 min in the control group. TFH at a dose of 300 micro g/kg, intravenously administered 15 min before the rose bengal injection, significantly prolonged it to 11.6 +/- 1.0 min (P < 0.05), a similar effect on in-vivo thrombogenesis to that of aspirin. TFH at a concentration of 3.0 micro g/ml significantly (P < 0.01) inhibited in vitro platelet aggregation induced by collagen (2 micro g/ml) in a concentration dependent manner, in contrast TFH did not affect aggregation induced by arachidonic acid (80 micro M) and ADP (0.3 micro M). The results of the present study, in which TFH prevented in-vivo thrombogenesis, probably due to inhibition of platelet aggregation, suggest a possible clinical approach for the prevention of thrombosis.

Effects of Bak Foong Pill on blood coagulation and platelet aggregation

The effects of Bak Foong Pill (BFP, also known as Bai Feng Wan), a preparation of crude drugs in wide clinical use for treatment of gynecological disorders, on blood coagulation and platelet aggregation were investigated. The anticoagulant effect of BFP was evaluated by using thrombin time (TT), prothrombin time (PT), and activated partial thromboplastin time (APTT) assays. Results showed that BFP 70% ethanol extract (BFP-E-ext) significantly prolonged the TT in a dose-dependent manner with values of 17.6, 38.3, and 50.4 s at concentrations of 4.0, 6.0, and 12.0 mg/ml, respectively. Whereas, the BFP-E-ext did not show significant prolonging effect in PT and APTT assays. The results suggest that the anticoagulant effect of BFP is mediated by directly blocking thrombin, the key enzyme in the blood coagulation cascade. BFP-E-ext significantly inhibited platelet aggregation induced by collagen and adenosine diphosphate (ADP) with inhibition percentages of 74 and 52% at a concentration of 6.0 mg/ml, respectively, whereas, it exhibited a weak inhibitory activity on platelet aggregation induced by archidonic acid (AA). Comparing to BFP-E-ext, the effects of BFP aqueous extract (BFP-W-ext) on both anticoagulant and antiplatelet activities were significantly less potent. Moreover, the effects of the 26 ingredients of BFP on blood coagulation and platelet aggregation were separately evaluated with 19 ingredient herbs exhibiting anticoagulant effect and 10 exhibiting antiplatelet effect. The anticoagulant and antiplatelet effects of BFP were collectively demonstrated by in vivo assays showing prolonged bleeding times after BFP treatment for two weeks. The results of the present studies may provide explanations for beneficial effects of BFP on the circulation and indicate its potential use for cardiovascular diseases.

Bioactive compounds in foods: their role in the prevention of cardiovascular disease and cancer

"Bioactive compounds" are extranutritional constituents that typically occur in small quantities in foods. They are being intensively studied to evaluate their effects on health. The impetus sparking this scientific inquiry was the result of many epidemiologic studies that have shown protective effects of plant-based diets on cardiovascular disease (CVD) and cancer. Many bioactive compounds have been discovered. These compounds vary widely in chemical structure and function and are grouped accordingly. Phenolic compounds, including their subcategory, flavonoids, are present in all plants and have been studied extensively in cereals, legumes, nuts, olive oil, vegetables, fruits, tea, and red wine. Many phenolic compounds have antioxidant properties, and some studies have demonstrated favorable effects on thrombosis and tumorogenesis and promotion. Although some epidemiologic studies have reported protective associations between flavonoids or other phenolics and CVD and cancer, other studies have not found these associations. Various phytoestrogens are present in soy, but also in flaxseed oil, whole grains, fruits, and vegetables. They have antioxidant properties, and some studies demonstrated favorable effects on other CVD risk factors, and in animal and cell culture models of cancer. However, because phytoestrogens act both as partial estrogen agonists and antagonists, their effects on cancer are likely complex. Hydroxytyrosol, one of many phenolics in olives and olive oil, is a potent antioxidant. Resveratrol, found in nuts and red wine, has antioxidant, antithrombotic, and anti-inflammatory properties, and inhibits carcinogenesis. Lycopene, a potent antioxidant carotenoid in tomatoes and other fruits, is thought to protect against prostate and other cancers, and inhibits tumor cell growth in animals. Organosulfur compounds in garlic and onions, isothiocyanates in cruciferous vegetables, and monoterpenes in citrus fruits, cherries, and herbs have anticarcinogenic actions in experimental models, as well as cardioprotective effects. In summary, numerous bioactive compounds appear to have beneficial health effects. Much scientific research needs to be conducted before we can begin to make science-based dietary recommendations. Despite this, there is sufficient evidence to recommend consuming food sources rich in bioactive compounds. From a practical perspective, this translates to recommending a diet rich in a variety of fruits, vegetables, whole grains, legumes, oils, and nuts.

Protective effect of rutin on paracetamol- and CCl4-induced hepatotoxicity in rodents

Rutin, a well-known flavonoid was investigated for its possible protective effect against paracetamol- and CCl(4)-induced hepatic damage. Paracetamol produced 100% mortality at the dose of 1 g/kg in mice while pre-treatment of animals with rutin (20 mg/kg) reduced the death rate to 40%. Oral administration of a sub-lethal dose of paracetamol (640 mg/kg) produced liver damage in rats as manifested by the rise in serum level of transaminases (AST and ALT). Pre-treatment of rats with rutin (20 mg/kg) prevented the paracetamol-induced rise in serum enzymes. The hepatotoxic dose of CCl(4) (1.5 ml/kg; orally) also raised the serum AST and ALT levels. The same dose of rutin (20 mg/kg) was able to prevent the CCl(4)-induced rise in serum enzymes. Rutin also prevented the CCl(4)-induced prolongation in pentobarbital sleeping time confirming its hepatoprotectivity. These results indicate that rutin possesses hepatoprotective activity and the presence of this compound in Artemisia scoparia may explain the folkloric use of the plant in liver damage.

Quinoline alkaloids and other constituents of Melicope semecarpifolia with antiplatelet aggregation activity

Three new quinoline alkaloids, 2-acetylevolitrine (1), 2-acetylpteleine (2), and semecarpifoline (3), along with 26 known compounds were isolated from the root bark of Melicope semecarpifolia. The structures of 1-3 were elucidated by means of spectral analysis. In addition, (2S)-(--)-7,8-dimethoxyplatydesmine (4), cis-(+)-7,8-dimethoxymyrtopsine (5), and (3R)-(--)-8,9-dimethoxygeibalansine (6) were isolated as new natural products. Several of these isolates were determined as exhibiting significant antiplatelet aggregation activities in vitro.

Inhibitory effects of xanthones on platelet activating factor receptor binding in vitro

Nine naturally occurring xanthones were investigated for their platelet activating factor (PAF) receptor binding inhibitory effects using rabbit platelets. 2-(3-methylbut-2-enyl)-1,3,5-trihydoxyxanthone, macluraxanthone, 1,3,5-trihydroxy-6,6'-dimethylpyrano(2',3':6,7)-4-(1,1-dimethylprop-2-enyl)xanthone, 6-deoxyjacareubin and 2-(3-methylbut-2-enyl)-1,3,5,6-terahydroxyxanthone showed strong inhibition with IC50 values of 4.8, 11.0, 21.0, 29.0 and 44.0 microM, respectively. The prenyl group at C-2, the dimethylprop-2-enyl group at C-4 and the hydroxyl group at C-5 are all beneficial to the binding of xanthones to the PAF receptor. The results revealed that xanthones can represent a new class of natural PAF receptor antagonists.

Advances in flavonoid research since 1992

Some of the recent advances in flavonoid research are reviewed. The role of anthocyanins and flavones in providing stable blue flower colours in the angiosperms is outlined. The contribution of leaf flavonoids to UV-B protection in plants is critically discussed. Advances in understanding the part played by flavonoids in warding off microbial infection and protecting plants from herbivory are described. The biological properties of flavonoids are considered in an evaluation of the medicinal and nutritional values of these compounds.

Supplementation with quercetin markedly increases plasma quercetin concentration without effect on selected risk factors for heart disease in healthy subjects

The purpose of this double-blind study was to investigate the influence of adding a quercetin-containing supplement to the diet on plasma quercetin status, serum/platelet fatty acid levels and risk factors for heart disease. Healthy men and women with cholesterol levels of 4.0-7.2 mmol/L, consumed four capsules daily of either a quercetin-containing supplement (1.0 g quercetin/d) or rice flour placebo for 28 d. Quercetin intakes were approximately 50-fold greater than the dietary intakes associated with lower coronary heart disease mortality on the basis of epidemiologic studies. Subjects consuming quercetin-containing capsules had plasma quercetin concentrations approximately 23-fold higher than those of subjects consuming the control capsules. Quercetin supplementation did not modify serum total, LDL or HDL cholesterol or triglyceride levels. There were also no alterations of other cardiovascular disease or thrombogenic risk factors, including platelet aggregation, platelet thromboxane B2 production, blood pressure or resting heart rate. Furthermore, there was no effect on the levels of (n-6) or (n-3) polyunsaturated fatty acids in serum or platelet phospholipids. In conclusion, supplementation with quercetin-containing capsules markedly enhanced the plasma quercetin concentration but had no effect on other cardiovascular or thrombogenic risk factors.

A tumor cell growth inhibitor from Polygonum hypoleucum Ohwi

Polygonum hypoleucum Ohwi (P. hypoleucum Ohwi) has been used as a Chinese medicine for a long time. In the present study, four anthraquinones, emodin, emodin 1-O-beta-D-glucoside (49A), physcion (62A), and physcion 1-O-beta-D-glucoside (50A) were identified from P. hypoleucum Ohwi and their inhibitory effects on various tumor cells proliferation were investigated. On a percentage basis, emodin had the highest suppressing activity on the various tumor cells proliferation. At 10 microg/ml, the percentage inhibition on K562 cells proliferation for emodin, 49A, 62A, and 50A were 97+/-3.4%, 18+7.3%, 24+/-3.6%, and 31+/-8.9%, respectively. However, inhibitory activities of 10 microg/ml of emodin, 49A, 62A, or 50A on Raji cells proliferation were 98+/-5.0%, 25+/-5.0%, 22+/-3.2%, and 28+/-4.3%, respectively. It was also found that the both C1 and C3 positions of emodin were important for antitumor action. The IC50s of emodin, 49A, 62A, and 50A on various tumor cells were also calculated. The IC50 of emodin on K562 cells was significantly lower than on Raji, HeLa, Calu-1, Wish, and Vero cells (1.5+/-0.2 vs. 2.8+/-0.4 microg/ml, P < 0.01 ;1.5+/-0.2 vs. 8.4+/-1.6 microg/ml; 1.5+/-0.2 vs. 8.9+/-1.0 microg/ml; 1.5+/-0.2 vs. 8.7+/-0.5 microg/ml; 1.5/-0.2 vs. 3.5+/-0.12 microg/ml; P < 0.001). The results indicated that K562 and Raji cells were more sensitive to emodin treatment. Cell viability test indicated that inhibitory effect of emodin on various tumor cell lines was not through direct cytotoxicity. It suggested P. hypoleucum Ohwi included a tumor cell growth inhibitor.