Does garlic have a role as an antidiabetic agent?

Abstract

Diabetes affects a large segment of the population worldwide, and the prevalence of this disease is rapidly increasing. Despite the availability of medication for diabetes, traditional remedies are desirable and are currently being investigated. Garlic (Allium sativum), which is a common cooking spice and has a long history as a folk remedy, has been reported to have antidiabetic activity. However, there is no general agreement on the use of garlic for antidiabetic purposes, primarily because of a lack of scientific evidence from human studies and inconsistent data from animal studies. The validity of data from previous studies of the hypoglycemic effect of garlic in diabetic animals and the preventive effects of garlic on diabetes complications are discussed in this review. The role of garlic as both an insulin secretagogue and as an insulin sensitizer is reviewed. Evidence suggests that garlic's antioxidative, antiinflammatory, and antiglycative properties are responsible for garlic's role in preventing diabetes progression and the development of diabetes-related complications. Large-scale clinical studies with diabetic patients are warranted to confirm the usefulness of garlic in the treatment and prevention of diabetes.

Garlic (<i>allium sativum</i>) modulates the expression of angiotensin II AT<sub>2</sub> receptor in adrenal and renal tissues of streptozotocin-induced diabetic rats

“…This notion may be supported by the documented AT 2 -mediated activities in inhibiting aldosterone hypersecretion and regulating catecholamine levels in the adrenal gland [1,[7][8][9]49], inhibiting the sodium pump [53] and Na + -, K + -ATPase activity [20][21][22] in renal proximal tubules thereby promoting natriuresis/diuresis and hypotension, and inhibiting vasoconstriction and cell hypertrophy [7][8][9]18,19] thereby interfering with excessive renal glomerular and tubular remodeling. In this regard, our observations may lend support to the documented efficacy of garlic treatments in ameliorating diabetic complications in STZtreated rats [28][29][30][31][32][33][34][35][36] and further suggest that garlic may alleviate diabetic-induced hypertension and nephropathy by restoring the diabetic-induced loss of balance in AT 1 /AT 2 receptor expression in key target organs. Future studies on the significance of constituent garlic metabolites, acting individually or in concert, may clarify the mechanisms that underlie its beneficial capacity in modulating the expression of selective receptor molecules implicated in diabetes-associated disorders.…”

“…In experimental diabetes, sulfur-containing and non-sulfur constituents of garlic work synergistically to exhibit antithrombotic, antioxidant, hypocholesterolaemic, hypoglycaemic as well as hypotensive potentials, which collectively ameliorate the development and progression of diabetic complications, including nephropathy and hypertension [28][29][30][31][32][33][34][35][36]. Nonetheless, neither the precise mechanisms that underlie the anti-diabetic potentials of garlic nor the nature of the key receptor system(s) targeted, are fully understood.…”

“…In experimental diabetes, garlic, used either as a whole raw extract or as isolated organosulphur constituents, is one of the best studied herbal remedies with documented anti-diabetic activities [28][29][30][31][32]. These activities include lowering serum glucose and cholesterol levels [30,31,33], inhibiting Ang II and promoting vasodilatation [29], preventing adrenal hypertrophy [34], attenuating oxidative stress [35], inhibiting the formation of advanced glycation endproducts [36], ameliorating hypertension and delaying the progression of diabetic nephropathy [31,32,35,36]. Nonetheless, the potential of garlic in targeting the level of expression of Ang II receptors is, as yet, not fully explored.…”

Antidiabetic effect of combined spices ofAllium sativum,Zingiber officinaleandCapsicum frutescensin alloxan-induced diabetic rats

“…Although each of the spices (garlic, ginger and pepper) has been reported to exhibit antidiabetic activities such as increasing insulin secretion, and lowering of blood glucose and urine sugar (Tolan et al 2001;Liu et al 2007;Gall & Shenkute 2009;Rackova et al 2013), there is no report on the antidiabetic action of a combination of the three spices. In view of the above effectiveness of the spices for diabetics, it is proposed to formulate a combination of the three and evaluate the efficacy of the combined spices compared with a reference drug, glibenclamide.…”

Analysis of cooking spices in natural waters

“…Humans use spices to enhance the flavor of food and mask bitter flavors in medicines (Dignum et al 2001). Because many spices have antibacterial or medicinal properties (Alpers 2009;Liu et al 2007;Thangapazham et al 2006), they are often used in homeopathic treatments. Demand for spices often exceeds their availability from natural sources (Dignum et al 2001), and thus many common cooking spices are also produced synthetically (e.g., vanilla, cinnamon, limonene).…”