Garlic Abstracts

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The following is a collection of garlic abstracts from published scientific research and papers.


Riggs DR, DeHaven JI, Lamm DL

Allium sativum (garlic) treatment for murine transitional cell carcinoma.

In: Cancer (1997 May 15) 79(10):1987-94

BACKGROUND: Currently, immunotherapy with Bacillus Calmette-Guerin (BCG) is the most effective treatment for superficial bladder carcinoma, but treatment-related toxicity may limit its use in some patients. Alternative treatments are needed for patients who fail to respond to BCG immunotherapy. Allium sativum (AS), or garlic, is known to have a broad range of biologic activities, including immune stimulation and reported antitumor activity. For these reasons, the authors conducted a series of experiments designed to explore the possible therapeutic effects of AS in the MBT2 murine bladder carcinoma model. METHODS: C3H/HeN mice were randomized prior to initiation of each experimental protocol. Mice received 1 x 10(3) MBT2 cells in 0.1 mL RPMI-1640, administered subcutaneously into the right thigh, on Day 0 of the experiment. AS was injected at the site of tumor transplantation on Day 1 and at 2- to 7-day intervals up to Day 28. To evaluate the effects of oral AS in this model, treatment was initiated 30 days prior to tumor inoculation and continued for 30 days after tumor inoculation. Animals in all experiments were followed for tumor incidence, tumor growth, and survival. RESULTS: In the initial experiments, subcutaneous AS significantly reduced tumor volume compared with the saline control (P < 0.05). Unfortunately, treatment-related death was also observed, requiring reduction in the total dose of AS. Animals that received 5 weekly immunizations of AS (5 mg, 5 mg, 1 mg, 1 mg, and 1 mg; cumulative dose = 13 mg) had significantly reduced tumor incidence, tumor growth, and increased survival when compared with animals that received the saline control. No treatment-related deaths were observed with this treatment schedule. To determine whether systemic AS administration might be effective, orally administered AS was tested at doses of 5 mg, 50 mg, and 500 mg per 100 mL of drinking water. Mice that received 50 mg oral AS had significant reductions in tumor volume (P < 0.05) when compared with animals that received the saline control, and mice that received 500 mg oral AS had significant reductions in both tumor volume and mortality (P < 0.05). CONCLUSIONS: The significant antitumor efficacy of subcutaneous and oral AS warrants further investigation and suggests that AS may provide a new and effective form of therapy for transitional cell carcinoma of the bladder.

Institutional address: Department of Urology West Virginia University School of Medicine Morgantown 26506 USA.



Lawson LD, Ransom DK, Hughes BG

Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic products.

In: Thromb Res (1992 Jan 15) 65(2):141-56

The inhibitory effects of adenosine and 16 quantitatively determined organosulfur compounds derived from garlic cloves or commercial garlic preparations on collagen stimulated in vitro platelet aggregation in whole blood were determined. An estimation of the anti- aggregatory activity of several brands of the major types of commercial garlic preparations was determined from the activities of the individual compounds present in each sample. In platelet rich plasma (PRP) most of the anti-aggregatory activity of garlic clove homogenates was due to adenosine; however, in whole blood neither adenosine nor the polar fraction had any effect and all of the anti- aggregatory activity was due to allicin and other thiosulfinates. Allicin was equally active in whole blood and PRP. Among brands there was a several-fold variation in content of the organosulfur compounds and activity for all types of garlic products tested. The best garlic powder tablets were equally as active as clove homogenates whereas steam-distilled oils were 35% as active and oil-macerates (due to low content) only 12% as active. A garlic product aged many months in aqueous alcohol had no activity. For steam-distilled oils, most of the activity was due to diallyl trisulfide. For the oil-macerates, most of the activity was due largely to the vinyl dithiins. Ajoene, an exclusive component of the oil-macerates, had highest specific activity of all the compounds tested but, because of its low concentration, had only 13% of the activity of diallyl trisulfide and 3% of the activity of allicin. Compounds which may be active in vivo are discussed.



Jain AK, Vargas R, Gotzkowsky S, McMahon FG

Can garlic reduce levels of serum lipids? A controlled clinical study.

In: Am J Med (1993 Jun Jun) 94(6):632-5

PURPOSE: To assess the effects of standardized garlic powder tablets on serum lipids and lipoproteins, glucose, and blood pressure. SUBJECTS AND METHODS: Forty-two healthy adults (19 men, 23 women), mean age of 52 +/- 12 years, with a serum total cholesterol (TC) level of greater than or equal to 220 mg/dL received, in a randomized, double-blind fashion, either 300 mg three times a day of standardized garlic powder in tablet form or placebo. Diets and physical activity were unchanged. This study was conducted in an outpatient, clinical research unit. RESULTS: The baseline serum TC level of 262 +/- 34 mg/dL was reduced to 247 +/- 40 mg/dL (p < 0.01) after 12 weeks of standard garlic treatment. Corresponding values for placebo were 276 +/- 34 mg/dL before and 274 +/- 29 mg/dL after placebo treatment. Low-density lipoprotein cholesterol (LDL-C) was reduced by 11% by garlic treatment and 3% by placebo (p < 0.05). There were no significant changes in high-density lipoprotein cholesterol, triglycerides, serum glucose, blood pressure, and other monitored parameters. CONCLUSIONS: Treatment with standardized garlic 900 mg/d produced a significantly greater reduction in serum TC and LDL-C than placebo. The garlic formulation was well tolerated without any odor problems.

Institutional address: Clinical Research Center New Orleans Louisiana 70112.



Mader FH

Treatment of hyperlipidaemia with garlic-powder tablets. Evidence from the German Association of General Practitioners’ multicentric placebo-controlled double-blind study.

In: Arzneimittelforschung (1990 Oct Oct) 40(10):1111-6

In a multicentric placebo-controlled randomised study the effect of standardized garlic-powder tablets (Kwai, Sapec) in the treatment of hyperlipidaemia was investigated. A total of 261 patients of 30 general practitioners in West Germany with total cholesterol and/or triglyceride values more than 200 mg/dl (mostly hyperlipoproteinaemia type II a/II b) took part in the study. Patients were randomly allocated to take tablets containing a total of 800 mg garlic powder (standardized to 1.3% of alliin content) daily or the same number of placebo tablets for 16 weeks (monthly controlled). 221 patients were used for statistical analysis of total cholesterol and 219 patients for the analysis of triglyceride values. Mean serum cholesterol levels dropped in the verum group from 266 to 235 mg/dl (i.e. 12%) during the 4 month treatment period, mean triglyceride values fell in the verum group from 226 to 188 mg/dl (i.e. 17%). The best cholesterol lowering effects were seen in the patients with initial total cholesterol values between 250-300 mg/dl. The difference between the verum and placebo group was highly significant (p less than 0.001). A mild garlic smell was observed in up to 21% of the verum group and up to 9% in the placebo group. Only one of the patients left the study for this reason. Standardized garlic tablets have been shown to be effective in the treatment of hyperlipidaemia by lowering total cholesterol values by an average of 12% and triglyceride values by an average of 17%.

Institutional address: Study Group on Phytotherapy of the German Association of General Practitioners Nittendorf.



Phelps S, Harris WS

Garlic supplementation and lipoprotein oxidation susceptibility.

In: Lipids (1993 May May) 28(5):475-7

Interventions which make serum lipoproteins less susceptible to oxidation may be antiatherogenic. The antioxidant properties of garlic which have been demonstrated in vitro led us to investigate the effects of garlic supplements on lipoprotein oxidation susceptibility in humans. Ten healthy volunteers were given 600 mg/d of garlic powder (6 tablets of Kwai) for two weeks in a placebo- controlled, randomized, double-blind crossover trial. We found that although serum lipid and lipoprotein levels were not lowered in this short time period, the ex vivo susceptibility of apolipoprotein B- containing lipoproteins to oxidation was significantly decreased (- 34%). Because garlic has been reported to beneficially affect serum lipid levels, platelet function, fibrinolysis and blood pressure, this additional effect of retarding lipoprotein oxidation may contribute to the potential antiatherosclerotic effect of garlic.

Institutional address: Department of Medicine University of Kansas Medical Center Kansas City 66160.



Kiesewetter H, Jung F, Jung EM, Mroweitz C, Koscielny J, Wenzel E

Effect of garlic on platelet aggregation in patients with increased risk of juvenile ischaemic attack.

In: Eur J Clin Pharmacol (1993) 45(4):333-6

A platelet-inhibiting effect is described for garlic. In this double- blind, placebo-controlled study on 60 voluntary subjects with cerebrovascular risk factors and constantly increased platelet aggregation it was demonstrated that the daily ingestion of 800 mg of powdered garlic (in the form of coated tablets) over 4 weeks led to a significant inhibition of the pathologically increased ratio of circulating platelet aggregates and of spontaneous platelet aggregation. The ratio of circulating platelet aggregates decreased by 10.3%, from 1.17 +/- 0.08 to 1.05 +/- 0.11 (P < 0.01), and spontaneous platelet aggregation by 56.3%, from 40.7 +/- 23.3 to 17.8 +/- 23.2 degrees (P < 0.01) during the garlic phase. There were no significant changes in the placebo group. The parallel group comparison (garlic versus placebo) revealed a significantly different ratio of circulating platelet aggregates after 4 weeks of treatment (P < 0.05). After the 4-week wash-out phase the values increased again to 1.19 +/- 0.32 and 34.9 +/- 28.7 degrees, reaching the initial values (run-in phase prior to the ingestion of garlic). Since garlic is well tolerated it would be worth testing it in a controlled clinical trial for usefulness in preventing disease manifestations associated with platelet aggregation.

Institutional address: Department of Clinical Haemostasiology and Transfusion Medicine University of the Saarland Homburg/Saar Germany.



Iqbal M, Athar M

Attenuation of iron-nitrilotriacetate (Fe-NTA)-mediated renal oxidative stress, toxicity and hyperproliferative response by the prophylactic treatment of rats with garlic oil.

In: Food Chem Toxicol (1998 Jun Jun) 36(6):485-95

Iron nitrilotriacetate (Fe-NTA) is a potent nephrotoxic agent. In this communication we show that Fe-NTA-mediated nephrotoxicity is diminished by 1 wk of oral daily pretreatment of male albino Wistar rats with garlic oil given by gavage at 50 or 100 mg/kg body weight/ml corn oil. Intraperitoneal Fe-NTA treatment at a dose level of 9 mg Fe/kg body weight/10 ml enhances renal microsomal lipid peroxidation and hydrogen peroxide generation which are accompanied by a decrease in the activities of renal antioxidant enzymes (e.g. catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase), and a depletion in the level of renal glutathione. Parallel to these changes, a sharp increase in blood urea nitrogen and serum creatinine has been observed. In addition, Fe- NTA treatment also enhances renal ornithine decarboxylase (ODC) activity and increases [3H]thymidine incorporation into renal DNA. Prophylactic treatment of animals with garlic oil before the administration of Fe-NTA resulted in the diminution of Fe-NTA mediated injury. The enhancement of renal lipid peroxidation and hydrogen peroxide generation was decreased. In addition, there was recovery of glutathione depletion and inhibition of the activities of antioxidant enzymes. Similarly, in animals given the higher dose of garlic oil (100 mg/kg body weight) the enhanced blood urea nitrogen and serum creatinine levels, which are indicative of renal injury, showed a reduction of about 30% and 40%, respectively, in comparison with the group treated with Fe-NTA alone. Pretreatment with garlic oil also ameliorated the Fe-NTA-mediated induction of ODC activity and enhancement of [3H]thymidine incorporation into DNA in a dose- dependent manner. Our data suggest that garlic oil is a potent chemopreventive agent and may suppress Fe-NTA-induced nephrotoxicity.

Institutional address: Department of Medical Elementology and Toxicology Faculty of Science Jamia Hamdard (Hamdard University) New Delhi India.