Synthetic Anticoagulants Research Articles

Potential of Garlic Filtrate as An Alternative Anticoagulant for Whole Blood Samples

Synthetic anticoagulants such as heparin, citric, and ethylenediaminetetraacetic acid (EDTA) are commonly used to prevent blood clots. In contrast, its widespread use in clinical laboratories is still constrained by price, its toxic nature, and its short shelf life. Therefore, an alternative material that is relatively cheap, non-toxic, and easy to obtain and process in a ready-to-use form is needed. Garlic contains allicin and ajoene, which are anti-platelet and anti-thrombogenic. This study’s aim is to explore the potential of garlic filtrate as an alternative anticoagulant. Blood from 16 individuals was used and separated into four groups: non-anticoagulant, 50 μL/mL garlic filtrate, 100 μL/mL garlic filtrate, and 150 μL/mL heparin, for a total of 64 treatments. The Lee and White method showed that non-anticoagulated blood had normal clotting times (mean 8 minutes and 56 seconds), whereas heparin plasma and garlic filtrate plasma had longer clotting times (more than 20 minutes); and this is statistically different based on the ANOVA test with a significance value (p) of 0.000 < 0.05. On spectrophotometric measurements, the levels of calcium ions in heparinized plasma and serum were 8.66 mg/dL and 8.52 mg/dL, respectively, while in garlic plasma filtrate of 50 μL/mL and 100 μL/mL were 4.13 mg/dL and 3.58 mg/dL, respectively; this is also statistically different based on the ANOVA test with a significance value of 0.000 < 0.05. The differences indicate that garlic filtrate can extend clotting time and reduce calcium ions therefore it is worth reviewing as an alternative anticoagulant.

In Vitro Investigation of Therapeutic and Anti-Coagulant Article DOI: Properties of Allium Sativum L. on Human Plasma

The current study was conducted to compare the anti-coagulant activity of different solvent-extracted fractions of garlic in a human blood sample in vitro. Two different solvents, namely rectified spirit and reverse osmosis (RO) water, were used to achieve the desired results. We used multiple extracting approaches to prepare different extract fractions of Allium sativum, both in ethanolic and aqueous extracts. These approaches included maceration, decoction, and soxhlet extraction methods. The concentration of each extract fraction was subjected to a primarily anti-coagulant screening method applied to a human blood sample in vitro by calculating the prothrombin time of human blood coagulation. The anti-coagulant activity of the extracts was determined by measuring the changes in prothrombin time with a null hypothesis value of p< 0.05. Additionally, a qualitative study of active phytochemical elements, such as alkaloids, flavonoids, steroids, proteins, carbohydrates, terpenoids, tannins, and glycosides was also conducted. The results indicated that all garlic extract fractions have a significant anti-coagulant potential. However, at 5 ppm concentration, soxhlet extraction extract showed the maximum anti-coagulant potential. Moreover, Garlic's aqueous extract also showed a significant anti-coagulant effect on human plasma. This observation conforms to the finding that the soxhlet extracted sample of garlic showed the highest activity of platelet aggregation inhibition. Furthermore, it was determined that aqueous and ethanolic extracts of Allium sativum showed a significant potential of anti-coagulation by comparing the current results with positively controlled EDTA and double oxalate acting as synthetic anti-coagulants.

Subacute administration of Astaxanthin inhibits vitamin K-dependent clotting factors in rats.

This study investigated the effect of Astaxanthin (ASTX) on levels and activities of the clotting factors in control rats. Untreated or ASTX-treated rats (10mg/kg, dissolved in DMSO) were used in this study. ASTX treatment was conducted for 10days daily. ASTX significantly decreased the platelet count and prolonged values of prothrombin and activated partial thromboplastin time (PT and aPTT, respectively). Besides, it significantly reduced serum levels of vitamin K and the plasma activities and hepatic expression of vitamin K-dependent factors (FII, FVII, FIX, and FX) without altering the activities or levels of all other clotting factors nor plasma levels of fibrinogen or von Willebrand Factor. These effects were associated with a reduction in serum and fecal levels of cholesterol and triglycerides and lower serum levels of LDL-c. In conclusion, ASTX exerts an in vivo hypocoagulant effects mediated by the inhibition of vitamin K-dependent factors. PRACTICAL APPLICATIONS: The findings presented here are the first that show the ability of Astaxanthin (ASTX) to inhibit coagulation in rats by suppressing the circulatory levels of Vitamin K and decrease the synthesis and release of all Vitamin-K dependent factor (FII, FVII, FIX, and FX). Since some synthetic anti-coagulants had side effects, these findings may illustrate ASTX as a natural anti-coagulant with fewer side effects that require further investigation in more clinical trials. Besides, awareness should be established for those individuals with some bleeding disorders who are being treated with ASTX for other beneficial effects.

Microbial biosynthesis of the anticoagulant precursor 4-hydroxycoumarin

4-Hydroxycoumarin (4HC) type anticoagulants (for example, warfarin) are known to have a significant role in the treatment of thromboembolic diseases--a leading cause of patient morbidity and mortality worldwide. 4HC serves as an immediate precursor of these synthetic anticoagulants. Although 4HC was initially identified as a naturally occurring product, its biosynthesis has not been fully elucidated. Here we present the design, validation, in vitro diagnosis and optimization of an artificial biosynthetic mechanism leading to the microbial biosynthesis of 4HC. Remarkably, function-based enzyme bioprospecting leads to the identification of a characteristic FabH-like quinolone synthase from Pseudomonas aeruginosa with high efficiency on the 4HC-forming reaction, which promotes the high-level de novo biosynthesis of 4HC in Escherichia coli (~500 mg l⁻¹ in shake flasks) and further in situ semisynthesis of warfarin. This work has the potential to be scaled-up for microbial production of 4HC and opens up the possibility of biosynthesizing diverse coumarin molecules with pharmaceutical importance.

Nuevas estrategias terapéuticas para la prevención del ictus en pacientes con fibrilación auricular: perspectiva desde atención primaria

Atrial fibrillation (AF) is the most common sustained arrhythmia, which leads to a higher number of hospital admissions and is the main cause of stroke of cardioembolic origin. According to the recommendations of the clinical practice guidelines, therapeutic strategy in AF has as its priority objectives, among others, the correction of the rhythm disorder with reversion, control of the heart rate, and prevention of thromboembolism. Anticoagulant treatment with warfarin or acenocoumarol is the keystone to the prevention of stroke in patients with AF, and has been the standard treatment for more than half a century. Their use in clinical practice, although it is widely unknown, requires regular monitoring to maintain the correct dose, which makes it difficult to be accepted by patients and doctors. The new oral synthetic anticoagulants are an important advance in the prevention of stroke and systemic embolism in patients with FA. Some of them, such as dabigatran, have recently been approved in the USA and Canada in the indication of arterial thromboembolic complications in patients with AF. If this indication, as is expected, is approved in our country, the importance of the role of coumarin derivatives (Sintrom ®) will not last much longer.

The Role of Leukocytes in Disseminated Intravascular Coagulation Associated with Sepsis

Leukocytes play a pivotal role in the pathogenesis of disseminated intravascular coagulation (DIC) and multiple organ failure associated with sepsis. Cytokines such as tumor necrosis factor-a (TNF-α) and interleukin-1β (IL-1β) activate monocytes, neutrophils and endothelial cells. TNF-α increases the expression of tissue factor on surfaces of both monocytes and endothelial cells and decreases the anticoagulant potential of endothelial cells, thereby inducing intravascular coagulation. These cytokines also inhibit the fibrinolytic activity by increasing the endothelial production of plasminogen activator inhibitor-1. These cytokines activate neutrophils to release the various inflammatory mediators such as neutrophil elastase and oxygen free radicals, both of which are capable of damaging endothelial cells. Activated neutrophils damage endothelial cells by adhering to endothelial cells through interaction with E-selectin or ICAM-1, endothelial leukocyte adhesion molecules, expression of which are increased by the actions of these cytokines. Both microthrombus formation and the endothelial cell damage could lead to multiple organ failure by inducing microcirculatory disturbances. Among physiological anticoagulants, antithrombin, activated protein C and tissue factor pathway inhibitor exert anti-inflammatory activity by inhibiting leukocyte activation. Gabexate mesilate and nafamostat mesilaste, synthetic anticoagulants, also inhibit leukocyte activation. The reduction of both coagulation abnormalities and inflammatory responses by using these therapeutic agents could be useful in the treatment of DIC associated with sepsis.

Stability of prothrombin times in sheep dosed with natural and synthetic anticoagulants

Sheep were dosed with natural and synthetic anticoagulants to prolong prothrombin time (PT) in the one stage PT test. The stability of subsequent values of PT of up to 40 seconds was measured at various times over a 24 hour period in plasma and whole blood stored at 0, 20 and 30 degrees C, representing ideal to unsuitable conditions of sample preparation and storage. In contrast to cautions in the literature, the various treatments had little influence on PT. These findings should encourage the use of PT in field diagnosis and research in sheep by surmounting the tenet of the difficulty in effectively preserving blood samples for PT determinations.

The Effect of Two Synthetic Anticoagulant Drugs (Coumarin and Inandione) in the Ewe

SUMMARY Synthetic anticoagulants of the coumarin and inandione types were administered to ewes. In the first trial, 3 groups (6, 8 and 8 animals) were treated with oral warfarin, intravenous warfarin and oral phenindione respectively. Doses similar to those given in human practice did not depress the coagulation activity. Only when the doses were greatly increased (io times for intravenous warfarin and 5 to 6 times for oral warfarin and phenindione) did the prothrombin activity level drop to a level comparable to the therapeutic level in human practice. At that level, the variability of response became very great and unpredictable. In a second trial, using a Latin square design, 12 ewes received doses of between 200 to 700 mg. of oral warfarin at weekly intervals. Twenty-four hr. after administration the coagulation activity was reduced in response to all doses, but no differences were discerned between the doses. After 48 hr. there was a positive linear relationship between dose level andthe depression in coagulation activity. Seventy-two hr. after administration coagulation activity had returned to a level similar to that prior to the dosing.

The anticoagulant activity and toxicity of laminarin sulphate K.

Abstract Four samples of sulphated laminarin, with differing degrees of sulphation, and two samples of fucoidin were examined for anticoagulant activity. Laminarin sulphate K, with 1·83 sulphate groups per glucose unit, showed anticoagulant activity about a third as potent as heparin. It did not cause agglutination of rabbit platelets either in vivo or in vitro, but it proved fatal to rabbits when given intravenously twice daily for periods of seven to twelve days, at a dose approximately three times the clinical dose. It was extremely toxic to guinea pigs in single small intravenous doses and produced the “anaphylactoid” phenomenon associated with some other toxic synthetic anticoagulants. Laminarin sulphate K was too toxic to justify clinical trials.

Synthetic anticoagulants. I. 1‐Alkoxy‐2,2‐bis‐(4‐hydroxy‐coumarinyl‐3) ethanes

AbstractNew synthetic anticoagulants were obtained in the series of 1‐alkoxy‐2,2‐bis‐(4‐hydroxy‐coumarinyl‐3)ethanes (III). In the rabbit the most active members of this group are as active as dicoumarol (I), while they equal ethyl biscoumacetate (II) with respect to resorption and rapid elimination. Clinical investigations are in progress.

Influence of Synthetic Polysaccharid Sulfuric Acid Esters on the Thrombocytes in vivo and in vitro.

Summary.It is demonstrated that some synthetic anticoagulants of the polysaccharid sulfuric acid ester group (chitin, cellulose and starch sulfuric acid esters) on intravenous injection in rabbits produce an agglutination of the thrombocytes and reduce the number of circulating platelets. This effect is of rather short duration and completely reversible. The toxicity of these substances reported by some authors may be due to the phenomenon demonstrated here.The mucoitin polysulfuric acid ester (heparin) found in the animal organism does not have the same effect on the thrombocytes.

Anti-Coagulants and Complementary Activity

Summary Heparin, capable of reacting with prothrombin or thrombin (20), inactivates complement only in quantities out of all proportion to its anti-coagulative ability. The synthetic anti-coagulants, the sodium salts of polyvinyl sulfuric and cellulose sulfuric acids, are from 75 to 100 times as anti-complementary as heparin, while possessing only 1/15 of the anti-coagulative ability of the purified heparins. Anti-coagulants capable of reacting with calcium, failed to inactivate complement under the conditions employed. Protamine, which probably inhibits coagulation by reacting with the thromboplastic factor (20), likewise required amounts for complement inactivation out of proportion to its anti-coagulative ability. The anti-complementary action of the anti-coagulants may be attributed to their acidic or basic nature, and to their high molecular size. No definite correlation exists between the inactivation of complement and the inhibition of coagulation.