Effects of garlic on platelet biochemistry and physiology

Abstract

Increased platelet aggregation plays a significant role in the aetiology of cardiovascular disease, and is complex involving multiple mechanisms. On platelet activation, there is a transient increase in free cytoplasmic calcium (Ca(2+)), thromboxane A2 generation, and the activation of the fibrinogen receptor GPIIb/IIIa. Other modulators are also involved in platelet aggregation and include lipoxygenase metabolites, protein kinase C, cyclic adenosine monophosphate (cAMP), cyclic guanine monophosphate (cGMP) and nitric oxide (NO). Garlic is reported to prevent cardiovascular disease by multiple effects, one of which is the inhibition of platelet aggregation and its ability to do this has been extensively investigated in vitro, however, in vivo studies are limited. In vitro studies indicate that garlic prevents inhibition of platelet aggregation by inhibiting cyclooxygenase activity and thus thromboxane A2 formation, by suppressing mobilization of intraplatelet Ca2+, and by increasing levels of cAMP and cGMP. Garlic also displays strong antioxidant properties and activates nitric oxide synthase (NOS), leading to an increase in platelet-derived NO. It can also interact directly with the GPIIb/IIIa receptors, thus reducing the ability of platelets to bind to fibrinogen. It is concluded that garlic inhibits platelet aggregation by multiple mechanisms and may have a role in preventing cardiovascular disease.

Garlic extract induces intestinal P-glycoprotein, but exhibits no effect on intestinal and hepatic CYP3A4 in humans

“…However, it has been previously reported that erythromycin is also a PGP substrate and that the concurrent administration of a PGP inhibitor may increase hepatic erythromycin metabolism and result in false positive EMBRTs, i.e. increases in the EMBRT without CYP3A4 induction (Frassetto et Page 13 , 2007, , Kurnik et al, 2006. In our study, the focus was on PGP and 3A4 induction and no change in EMBRT was observed.…”

“…Both experimental data, and data from controlled clinical trials, suggest that garlic preparations may lower lipid levels and have anti-hypertensive and anti-coagulant properties, which could lower cardiovascular risk factors for patients (Stevinson et al, 2000, Ried et al, 2008, Rahman, 2007, O'hara et al, 1998. The efficacy of garlic and its derivatives have been linked to the generation of organosulfurs, such as monosulfides, polysulfides, and ajoenes, by the body in response to the alliin contained in garlic (Iciek et al, 2009, Rose et al, 2005.…”

“…For example, St John's Wort has been shown to decrease the efficacy of several drugs, including oral contraceptives (Schwarz et al, 2003) and HIV protease inhibitors (Piscitelli et al, 2000). In these cases, the induction of several cytochrome P450 drug metabolizing enzymes and the intestinal efflux transporter P-glycoprotein (PGP) have been detected (Dürr et al, 2000).Both experimental data, and data from controlled clinical trials, suggest that garlic preparations may lower lipid levels and have anti-hypertensive and anti-coagulant properties, which could lower cardiovascular risk factors for patients (Stevinson et al, 2000, Ried et al, 2008, Rahman, 2007, O'hara et al, 1998. The efficacy of garlic and its derivatives have been linked to the generation of organosulfurs, such as monosulfides, polysulfides, and ajoenes, by the body in response to the alliin contained in garlic (Iciek et al, 2009, Rose et al, 2005.…”

Black Garlic Ameliorates Obesity Induced by a High-fat Diet in Rats

“…The pharmacological actions of garlic (Allium sativum L.) include antiobesity, antibacterial, antiviral, antihypertensive, blood glucose lowering, antithrombotic, antimutagenic, and antiplatelet actions [9,10,11,12,13,14]. Sheen et al [15] indicated that the garlic oil and its organosulfur compounds can be beneficial for the suppression of high-fat diet (HFD)-induced body weight gain in rats.…”

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“…15 Moreover, Allium sativum is a mood elevating and hepato-protective agent 16 which is also protective against protozoan infections [17][18][19][20] and reduces platelet aggregation. [13][14][15][16][17][18][19][20][21] The active compounds of Allium sativum are volatile oil, sulphur, iodine, zinc, manganese, phosphorus, potassium, selenium, vitamin A, vitamins B 1 , B 2 and B 6 and vitamin C. In addition to various antioxidants, it also contains more than eighty sulfur-containing compounds. Out of these substances, allicin is the most known.…”