Anti-platelet aggregation effects of extracts from Arbutus unedo leaves

Abstract

It is well known that platelet hyperactivity is a risk factor for cardiovascular diseases such as atherosclerosis, stroke and myocardial infarction. This study aimed to examine the effects of extracts enriched in flavonoids obtained from Arbutus unedo leaves on platelet aggregation. Rat platelets were prepared and incubated in vitro with different doses of the tested extracts, and aggregation was trigged by physiological agonists. Platelet treatment with increasing concentrations (0.1 -1 mg/ml) of diethyl ether extract (genins = free flavonoids) or ethyl acetate extract (hetrosidic flavonoids) inhibited platelet aggregation evoked by thrombin in a concentration-dependant manner. The IC50 values were 0.22 ± 0.03 and 0.36 ± 0.05 mg/ml for genins and heterosidic flavonoids respectively. Treatment with Arbutus unedo extracts also significantly reduced the initial rate of platelet aggregation. At 1 mg/ml, the rate inhibition was 97.8 ± 0.74 and 90.8 ± 1.55 % for genins and heterosidic flavonoids respectively. In addition, flavonoids significantly inhibited platelet aggregation induced by ADP, collagen or epinephrine. We conclude that Arbutus unedo extracts show antiaggregant effects due mainly to flavonoids. These results may partly explain the traditional use of Arbutus unedo leaves for the treatment of cardiovascular disorders such as hypertension.

Effects of Juglans regia Root Bark Extract on Platelet Aggregation, Bleeding Time, and Plasmatic Coagulation: In Vitro and Ex Vivo Experiments

“…The involvement of such compounds in hemostasis was already initiated in our laboratory. Flavonoids (genins and heterosidic flavonoids) isolated from Arbutus unedo [ 33 ] or Petroselinum crispum [ 6 ] inhibit platelet aggregation. More, Gadi et al [ 6 ] reported that the adhesion of human platelets to collagen under flow was greatly decreased by genins of Petroselinum crispum .…”

Antithrombotic, Antiaggregant and Anticoagulant Effect of Methanolic Fraction of Calamintha officinalis: In vitro and ex vivo Experiments

“…For polyphenols, flavonoids present a large group of natural products, widely distributed in plant, and exhibit an antiaggregant 29 and antithrombotic activities 30 . Some hypothesis are evoked to explain the antithrombotic activity of polyphenols such us inhibition of key enzymes involved in platelet function; cyclooxygenase and lipo-oxygenase 31 .…”

An Insight into Phytochemical, Pharmacological, and Nutritional Properties of Arbutus unedo L. from Morocco

“…It has been found that genins (free flavonoids) hetrosidic flavonoids reduced significantly thrombin-induced platelet aggregation with IC50 values of 0.22 ± 0.03 and 0.36 ± 0.05 mg/ml, respectively. In addition, at 1 mg/ml, these compounds reduced significantly the initial rate of platelet aggregation by 97.8 ± 0.74% and 90.8 ± 1.55% for genins and heterosidic flavonoids, respectively [ 44 ]. Thus, these findings clearly demonstrate that the anti-platelet effect of A. unedo is mainly attributed to flavonoids.…”

“…According to different toxicity tests, the use of A. unedo is devoid of any significant side effects and/or toxicity. Indeed, in an acute toxicity test performed in mice, we have demonstrated that the oral administration of A. unedo leaf aqueous extract at a dose up to 1200 mg/kg caused no mortality and no signs of adverse effects, demonstrating that the LD 50 value of the A. unedo aqueous extract was higher than 1200 mg/kg b.w in oral administration in mice [ 44 ]. In another acute toxicity test realized in mice, it has been reported that the A. unedo root aqueous extract exhibited LD 50 higher than 2000 mg/kg b.w with no adverse effect of this dose shown after single oral administration in mice [ 76 ].…”

“…Furthermore, experimental investigations of our group have shown that A. unedo extracts exhibited different biological properties including antioxidant, platelet antiaggregant, vasorelaxant, antihypertensive, and antidiabetic activities [37,[41][42][43][44][45][46][47][48][49]. In addition, the plant has been shown to contain different phytoconstituents such as flavonoids, tannins, phenolic acids, organic acids, α-tocopherol, carotenoids, anthocyanins, triterpenoids, fatty acids, sterols, vitamin c, fibers, calcium (Ca), potassium (K), magnesium (Mg), phosphorus (P), and other bioactive compounds [37,47,[50][51][52][53][54][55], which contribute to its various pharmacological and nutritional properties.…”