Effect of Armagnac fractions on human platelet aggregation in vitro and on rat arteriovenous shunt thrombosis in vivo probably not related only to polyphenols

Constituents and Antioxidant Activity of Bleeding Sap from Various Xinjiang Grapes

Objective:

Wine grape sap or bleeding sap of grapes (GBS) is commonly used in Xinjiang (China) for therapeutic aims. Do variations in composition related to region and variety affect its properties?

Methods:

GBS samples originating in various parts of Xinjiang (Turpan, Hotan, Kashgar, and Atush) were tested for phenols and polyphenols, polysaccharides, saponin, proteins, individual amino acids, and minerals. Their antioxidant activity was measured using ascorbic acid as reference.

Results:

Polyphenol content varied from 2.6 to 6.6 mg/L, polysaccharides 18.3–816 mg/L, saponin 6.25–106 mg/L, and protein 3.0–22.4 mg/L. Mineral elements and amino acids ranged from 6.20 to 201.2 mg/L and 0.06–118.7 mg/L, respectively. ·OH scavenging ability varied from 70% to over 90%, higher than Vitamin C. Grapes from Turpan had lower antioxidant activity than other grapes even though the polyphenol content was generally higher.

Conclusion:

Bleeding sap of Xinjiang grape is rich in amino acids, polysaccharides, polyphenols, and protein. The contents are different according to the origin, related possibly to species, climate, and environment. Antioxidant effects were not correlated with polyphenol content.

SUMMARY

Antioxidant activity of plants or plant extracts is often associated with polyphenols

Bleeding sap of grapes has strong antioxidant properties

Bleeding sap from different grape varieties from different parts of Xinjiang (China) had different polyphenol concentrations

There was no correlation of polyphenol concentrations with antioxidant activity.

Abbreviations used: GBS: Bleeding sap of grapes; PITC: phenyl isothiocyanate.

News from Tartary: an ethnopharmacological approach to drug and therapeutic discovery

Ethnopharmacology aims to identify new therapeutic agents based on their traditional use. It begins by the identification of disease states, and of the traditional therapies for these, most commonly herbals. Herbals of interest are selected from ethnopharmacological surveys, and tested on experimental models of the diseases of interest. Once the activity of the traditional remedy is demonstrated, including dose-dependence, if possible comparatively to reference medications, the active ingredients can be explored, if possible using bioguided extraction. Identified molecules can then be further developed as medicinal products or pharmaceutical medicines (e.g., artemisine), or the herbal product can be developed as such (e.g. St John's wort). We provide examples of various study programmes, concerning the antiplatelet and antithrombotic effects of Armagnac extracts from Southwest France; antithrombotic and antihypertensive effects of extracts of Ocimum basilicum L; antithrombotic, antihypertensive and antihyperlipidemic effects of Cydonia oblonga; Antiproliferative and antithrombotic effects of Abnorma Savda Munziq of traditional Uyghur medicine; and the antidiabetic and hepatoprotective effects of Centaurium erythraea Rafn, Artemisia herba-alba Asso and Trigonella foenum-graecum L., all in collaboration between University of Bordeaux, France, Xinjiang Medical University in Urumqi, China and University Mentouri in Constantine, Algeria.

Phytochemicals in Ischemic Stroke

Stroke is the second foremost cause of mortality worldwide and a major cause of long-term disability. Due to changes in lifestyle and an aging population, the incidence of stroke continues to increase and stroke mortality predicted to exceed 12 % by the year 2030. However, the development of pharmacological treatments for stroke has failed to progress much in over 20 years since the introduction of the thrombolytic drug, recombinant tissue plasminogen activator. These alarming circumstances caused many research groups to search for alternative treatments in the form of neuroprotectants. Here, we consider the potential use of phytochemicals in the treatment of stroke. Their historical use in traditional medicine and their excellent safety profile make phytochemicals attractive for the development of therapeutics in human diseases. Emerging findings suggest that some phytochemicals have the ability to target multiple pathophysiological processes involved in stroke including oxidative stress, inflammation and apoptotic cell death. Furthermore, epidemiological studies suggest that the consumption of plant sources rich in phytochemicals may reduce stroke risk, and so reinforce the possibility of developing preventative or neuroprotectant therapies for stroke. In this review, we describe results of preclinical studies that demonstrate beneficial effects of phytochemicals in experimental models relevant to stroke pathogenesis, and we consider their possible mechanisms of action.

Design, synthesis and biological evaluation of hydrogen sulfide releasing derivatives of 3-n-butylphthalide as potential antiplatelet and antithrombotic agents

In the present study, a series of hydrogen sulfide (H2S) releasing derivatives (8a–g and 9a–f) of 3-n-butylphthalide (NBP) were designed, synthesized and biologically evaluated. The most promising compound 8e significantly inhibited the adenosine diphosphate (ADP) and arachidonic acid (AA)-induced platelet aggregation in vitro, superior to NBP, ticlopidine hydrochloride and aspirin. Furthermore, 8e could slowly produce moderate levels of H2S in vitro, which could be beneficial for improving cardiovascular and cerebral circulation. Most importantly, 8e protected against the collagen and adrenaline induced thrombosis in mice, and exhibited greater antithrombotic activity than NBP and aspirin in rats. Overall, 8e could warrant further investigation for the treatment of thrombosis-related ischemic stroke.

Effect of traditional Uyghur medicine abnormal Savda Munziq extract on rabbit platelet aggregation in vitro and rat arteriovenous shunt thrombosis in vivo

OBJECTIVE

Abnormal Savda Munziq (ASMq) is a standard herbal preparation used in Uyghur traditional medicine to fight chronic diseases including cardiovascular, but its specific effects on thrombosis and platelet aggregation are unknown.

METHODS

Rabbit platelets were incubated with ASMq extract (10, 20, 40 µg/ml) for 15, 30, or 60 min, and aggregation was induced with ADP and collagen. In vivo, ASMq extract 2.97 g/kg, 5.94g/kg, 11.88 g/kg per os daily for 15 days were tested on thrombus wet weight in a rat model of arterio-venous bypass thrombosis. Plasma thromboxane B2 (TXB2) and 6-keto-PGF1a (6PG) were measured by radioimmunoassay. Aspirin (12 µg/ml and 5mg/kg) and saline were used as control in both experiments.

RESULTS

ASMq inhibited ADP and collagen-induced aggregation in vitro in a dose-dependent manner that increased over time, to a maximum of 6.4 ± 1.3% and 21.6 ± 4.0% for ADP and collagen, respectively, at one hour׳s incubation with the highest concentration, whereas the effects of aspirin (34.5 ± 2.2% and 41.9 ± 2.5%, respectively) were stable over time. In vivo, ASMq inhibited thrombus formation dose-dependently, by 70% at the highest dose, compared to 67% with aspirin. ASMq essentially did not change prostaglandin production, compared to the clear inhibition by aspirin.

CONCLUSION

Abnormal Savda Munziq extract inhibits dose-dependent platelet aggregation with ADP or collagen in vitro and thrombosis in vivo to values similar to those of aspirin, though unlike aspirin this effect does not seem mediated by an inhibition of cyclo-oxygenase.

Novel hybrids of optically active ring-opened 3-n-butylphthalide derivative and isosorbide as potential anti-ischemic stroke agents

In search of novel anti-ischemic stroke agents with higher potency than a known drug 3-n-butylphthalide (NBP), a series of hybrids ((S)- and (R)-5a-f) from optically active ring-opened NBP derivative and isosorbide were synthesized for evaluating their anti-ischemic stroke activity. Compound (S)-5e displayed the strongest activity in inhibiting the adenosine diphosphate (ADP) and arachidonic acid (AA)-induced platelet aggregation in vitro, with 10.0- and 8.4-fold more effectiveness than (S)-NBP, respectively. Furthermore, (S)-5e was stable in artificial gastrointestinal fluids and could penetrate the blood-brain barrier (BBB) with an appreciate lipid/water partition coefficient relative to (S)-NBP. More importantly, oral treatment with (S)-5e protected from acute thrombosis and inhibited the ischemia/reperfusion-related brain injury in animals. Our findings suggest that (S)-5e may be promising for further evaluation for the intervention of ischemic stroke.

Novel bioactivity of ellagic Acid in inhibiting human platelet activation

Pomegranates are widely consumed either as fresh fruit or in beverage form as juice and wine. Ellagic acid possesses potent antioxidative properties; it is known to be an effective phytotherapeutic agent with antimutagenic and anticarcinogenic qualities. Ellagic acid (20 to 80 μM) exhibited a potent activity in inhibiting platelet aggregation stimulated by collagen; however, it did not inhibit platelet aggregation stimulated by thrombin, arachidonic acid, or U46619. Treatment with ellagic acid (50 and 80 μM) significantly inhibited platelet activation stimulated by collagen; this alteration was accompanied by the inhibition of relative [Ca²⁺]_i mobilization, and the phosphorylation of phospholipase C (PLC)γ2, protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and Akt, as well as hydroxyl radical (OH^●) formation. In addition, ellagic acid also inhibited p38 MAPK and Akt phosphorylation stimulated by hydrogen peroxide. By contrast, ellagic acid did not significantly affect PKC activation and platelet aggregation stimulated by PDBu. This study is the first to show that, in addition to being considered a possible agent for preventing tumor growth, ellagic acid possesses potent antiplatelet properties. It appears to initially inhibit the PLCγ2-PKC cascade and/or hydroxyl radical formation, followed by decreased phosphorylation of MAPKs and Akt, ultimately inhibiting platelet aggregation.

Ellagitannins, ellagic acid and vascular health

Hydrolysable tannins are phenolic phytochemicals that show high antioxidant and free-radical scavenging activities. For this reason their potential effects preventing oxidative related diseases, such as cardiovascular diseases, have been largely studied. In vitro studies show that ellagitannins, at concentrations in the range 10-100 μM, show some relevant anti-atherogenic, anti-thrombotic, anti-inflammatory and anti-angiogenic effects, supporting the molecular mechanisms for the vascular health benefits. While there is good evidence supporting the vascular effects in vitro, the evidence on animal models or humans is much scarcer. The in vitro results often do not match the findings in the in vivo studies. This could be explained by the low bioavailability of the antioxidant ellagitannins and ellagic acid. The main ellagitannin metabolites circulating in plasma are ellagic acid microbiota metabolites known as urolithins, and they have lost their free-radical scavenging activity. They are present in plasma as glucuronide or sulphate conjugates, at concentrations in the nM range. Future studies should focus in the bioavailable metabolites, urolithins, and in the form (conjugated with glucuronic acid or sulphate) and concentrations (nM range) in which they are found in plasma. In this review we critically discuss the role of ellagitannins and ellagic acid on vascular health.