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GARLICMedical Science Discovers

New Uses for an Ancient Herb

By Stephen Laifer

"Garlic is the subjectof considerableresearch for its

medicinal properties,and new clinical

trials are yieldingproof of its role as

a powerfulantioxidant."

erbalists routinely elaim thatgarhc [AlUum sativwn) is the

world's longest-used medicinalfood. The therapeutie use of garliepredates written history by severalmillennia, with the earliest mentiondating back more than 5,()()0 yearsago to Sanskrit records in India.'Garlic was already a long-favoredremedy in ancient medicine 1.000years before the birth of Christ.Ancient Egyptians worshipped thespice as a god, valuing it so muchthat 15 pounds of garlic would pur-chase a healthy male slave.

A close relative of the onion,garlic's origins in the Kirgiz desertregion of Siberia have endowed itwith the ability to thrive in harshclimates and poor soil. The bulb'sadaptability played a significantrole in its becoming a staple cropin almost every civilization aroundthe globe. Even I.(K)O years ago,garlic was grown in virtually all theknown world and nearly universal-ly recognized as a medicinal plant.

Twentieth-century science rele-gated garlic to a state of relativeneglect medicinally, if not in thekitchen. In recent years, however.garlic has moved to the forefrontof an explosion of interest in natu-ral remedies. Accordine to the

UCLA Center for HumanNutrition in Los Angeles, dietsrich in plant foods are associat-ed with a reduced risk of heartdisease and cancer. These plantfoods contain phytochemicals thathave anti-cancer and anti-inflam-matory properties. Garlic andother white-green foods in theonion family contain allyl sul-phides, which may inhibit thegrowth of cancer cells.

Today, garlic is the subject ofconsiderable research for itsmedicinal properties, and newclinical trials are yielding proof ofits role as a powerful antioxidant.Garlic also shows promise in pro-tecting against heart disease,hypertension, and cancer.

SCAVENGING FREERADICALS

Implicated in many serious ill-nesses, free radicals are harmfulbyproducts of cellular metabo-lism. Antioxidants scavenge freeradicals.

Sulfur-containing compounds,found in all body cells, are indis-pensable to living organisms.Unlike humans, plants can useinorganic sulfur to synthesize

April 2005 LIFE EXTENSION 87

ALL ABOUTsulfur-containing amino acids.Many strong antioxidant com-pounds are rich in sulfur, includ-ing N-acetylcysteine. taurine.lipoic acid, and glutathione.Plants are an important source ofsulfur for humans, and garlic is amajor source of organosulfurcompounds.^

Recent studies in India havedemonstrated garlic's effective-ness in reducing oxidative stressin animals with high blood lipidlevels. Supplementation with gar-lie significantly countered thelipid-related depletion of intracel-lular antioxidants in Ihe liver andred blood cells.'' Two separatestudies focused on S-allylcysteine,a garlic-derived compound andwell-charaeterized scavenger offree radicals. S-allyleysteine scav-enges free radicals and reducesoxidalive stress."" In experimentalanimal models. S-allylcysteinehelped protect the nervous systemfrom neurotoxins and the kidneysagainst damage from reactive oxy-gen species.*"'

PROlECTING THEHEART

In horror movies, garlic isoften used to ward off vampires.Garlic does indeed protect theblood (and its major engine, theheart) from attack—not fromvampires, but from a subtlerenemy. In recent years, athero-sclerosis has emerged as one ofthe leading causes of death innations whose diets are dispro-portionately high in saturatedfats and cholesterol. A Czechstudy investigated garlic's inhibito-ry effect on the biosynthesis ofcholesterol and fatty acids. Positiveresults manifested in reducedarterial plaque and markedlydecreased accumulation of choles-terol in the vascular walls."

A Turkish team exploring gar-lic extract's effects on coronaryplaque formation saw similarresults. In test animals, sevenmonths of garlic supplementa-tion significantly decrea.sed theplaque surface area in the ani-mals' aortas." Another studyimplicated several sulfur-con-taining compounds isolated fromgarlic as highly active anti-thrombotic agents. This studyestablished that garlic could be asignificant inhibitor of plateletaggregation.'"

Eleven patients with athero-sclerosis were the focus of a six-month study on possible benefieialeffects of garlic extract at a dailydose of 1 milliliter per kilogram ofbody weight. Garlic supplemen-tation notably lowered levels ofthe oxidative marker malondi-

aldehyde in plasma and redblood cells; ingesting garlicextract also prevented oxidationreactions by eliminating oxidantstress." The study authorsconcluded, "it is possible thatreduced pcroxidalion processesmay play a part in some of thebeneficial effects of garlic in ath-erosclerotic diseases.""

Aged garlic extract has beenshown to reduce multiple cardio-vascular risk factors, includingblood pressure, cholesterol, andplatelet aggregation and adhe-sion, while stimulating the gener-ation of nitric oxide in endothelialcells.'- A recent, double-blind,plaeebo-controlled study evaluat-ed aged garlic extract's ability toinhibit vascular calcification, amarker of plaque formation inhuman coronary arteries, in 23patients with atheroselerosis.''The results suggested that agedgarlic extract may inhibit Ihe pro-gression of eoronar)' calcification,suggesting a therapeutic role forgarlic in patients at high risk forfuture eardiovascular events.''

TAKING THEPRESSURE OFF

Hypertension, or high bloodpressure, is a silent but potential-ly deadly disease. Researeh sug-gests that garlic supplementationmay provide important benefitsfor hypertensive patients.

Researchers at the Universityof Mississippi investigatedhypertension treatment using nat-ural, commonly available dietarysupplements and stress-reducing

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lifestyle modifications.' Garlicshowed the potential to reducesystolic blood pressure by at least9 mmHg and diastolic blood pres-sure by at least 5 mmHg."

A subsequent Turkish elinicaltrial took this evidence further,finding that garlic extract supple-mentation over four monthsmarkedly lowered systolic anddiastolic blood pressure values inhypertensive volunteer subjectswith high blood cholesterol." Inthose with normal blood pres-sure, garlic did not affect bloodpressure levels.'̂

ALLY INTHE CANCER WAR

For thousands of years, tradi-tional medical practitioners haveused garlic and other members ofthe Allium genus to treat cardio-vascular disease." Garlic's use asa remedy for tumors extends back

to Ihe Codex Ebers of 1550 BC,an Egyptian medical papyrus.'"Recent extensive research hasfocused on the anticarcinogcnicpotential of allium vegetables andtheir constituents, allylsulfides(organosulfur compounds) andfiavonoids.

Modern epidemiological stud-ies, well correlated with laborato-ry investigations, corroborate theevidence that higher intake ofallium products is associated withreduced risk of several cancers."The mechanisms proposed toexplain the cancer-preventiveeffects of garlic include inhibitionof tumor mutagcnesis, modula-tion of enzyme activities, andeffects on cell proliferation andtumor growth.''

Several garlic compounds,including allicin, induce apoptosis(programmed cell death) in vari-ous malignant human cells. Theseinclude breast, coiorectal. hepat-ic, prostate, and lymphoma cells.'"A growing number of clinica!studies are examining the proper-ties of ajoene. the major sulfur-containing compound purifiedfrom garlic. Ajoene has theadvantage of being more chemi-eally stable than allicin. andresearchers are investigating itspossible role in the preventionand treatment of cancer.'^"'

Cancer researchers have notedthat inhibition of the protea-some—an intracellular device bywhich damaged or unnecdedproteins are broken down—playsa key role in apoptosis and celleycle blockade in tumor cells. Ina recent French study of ajoene'seffects on the proteasome's

activities, researchers found thatajoene affected proteasome func-tion and activity both in vitro andin the living cell, and that theseeffects may account for ajoene'spotential anti-tumor action.'"

Topical application of ajoenehas produced significant clinicalresponse in patients with skinbasal cell carcinoma.'" Ajoeneinhibited proliferation andinduced apt)ptosis of humanleukemia CD34-negative cells,inducing 30% apoptosis inmyeloblasts from a chronicmycloid leukemia patient in blaslcrisis."' Even more significantly,ajoene profoundly enhanced theapoptotic effect of two chemo-therapeutic drugs, cytarabine(Cytosar') and fludarabine(Fludara' )."•

The list of cancers respondingto garlic treatment or supple-mentation continues to grow.Separate Chinese studies report-ed that the garlic componentallyl sulfidc demonstrated activi-ty against human bladder can-cer'" and liver cancer'' cells invitro. Another study reported onthe protective effects of garliccomponents in a rat model ofcolon carcinogenesis, noting thatgarlic inhibited cell prolifera-tion, induced apoptosis, andsuppressed the aetivity ofthe cyc!oo.xygcnase-2 (COX-2)enzyme.-

CETTING THE BENEFITS

Garlic has demonstrated fewtoxic side effects. While eatinggarlic cloves is a proven way to

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ALL ABOUTobtain the benefits of theirorganosulfides. unwelcome sideeffects include bad breath andperspiration. Fortunately, garlicsupplements provide all the bene-fits of eating raw garlic withoutthese undesirable effects.

REFERENCES

1. Riddle JM. Garlic's hi*itory as a medicine.Paper presented ai: American HerbalProducts Association Intcrnatiunal GarlicSymposium: July ?<]. 2(M)I.

2. Hebcr D. Vegetables. Iruils and phyto-cstrogcns in the prevcniion of diseases. 7Pi)slgrcul Med. 2()04 Apr:.')0(2):145-9.

3. Atmaca G. Antioxidant effects of sulfur-containing amino acids. YonseiMedJ. 2(H)4Ocl3i:4?(5):776-88.

4. Kcmpaiah RK. Srinivasan K. Influence ofdietary curcumin, capsaicin and garlic onthe anlioxidanl status of red blood cellsand lhe liver in high-fal-fed rals. Ann NuirMeiah. imA September :4S(5):3l4-2().

5. Kempaiah RK. Srinivusan K. Anlioxidantstatus uf red blood cells and liver in hyper-cholcslcroiemic rals fed hypolipidemicspices, tnt J Vimm Nutr Res. 2004May;74(3):199-208.

h. Pcrcz-Severiano K Rodriguez IVTCZ M ,Pcdraza-Chaverri J. et al. S-Allylcysteine.a garlic-derived antioxidant. amelioratesquinolinic acid-induced ncuroioxicity andoxidative damage in rats. Neurochem tnt.201)4 Dec:45(8): 1175-83.

7. Maldonado PD. Barrura D, Rivero I. et al.Antiosidanl S-allyicysteinc prevents gen-tamicin-induccd iixidative stress and renaldamage. Free Radk Blot Med. 2(H13 Augl:35(3):317-24.

8. Sovova M, Sova P Pharmaceutical impor-tance of Allium sativum L. .i. Hypoiipemiceffects in vitro and in vivo. Ceska SlovFarm. 2()04 May;53{3):l 17-23.

y. Durak A. Ozturk HS. Olcay b. Guven C.Effects of garlic extract supplcmc-ntationon blood lipid and antioxidani parametersand atherosclerotic plaque formalionprocess in cholesterol-fed rabbil^.J HerbPhanncother. 2(Hl2;2(2):iy-32.

10. liudolf MJ, Tikasu J, Fiorcs FR, cl al.Inhibiting progression of coronary calcifi-cation using aged garlic extract in patientsreceiving slalin therapy: a preliminarystudy. /Vfi- Med. 2IK)4 Nov;39(5):98.S-9i.

11. Wilbtirn A.I. King DS, Glisson J.Rockhold RW. Wofford MR. The naturaltreatment ut hypertension. 7 CHnHypertens. (Cirecimich.) 2004May;6(5):242-8.

12. Dunik I. Kavuicu M. Aytac B, et al.Effects of garlic extract eonsumption onblood lipid and oxidant/antioxidiintparameters in humans with high bloodcholesterol. J Nutr Biochem. 2004Jun:l.S(6):.173-7.

13. Sengupta A. Ghosh S. Bhattachatjee S.Allium vegetables in cancer prevention: anoverview. Asian Pac J Cancer Prev. 2(XW

14. Hassan HT. Ajoene (natural garlic eom-pound): a new anti-Iuukaemia agcnl forAML therapy. Leuk ties. 2004Jul:28(7):667-71.

15. Ledezma E. Apitz-Castro R. Cardier J.Apoptotic and anti-adhesion effeet ofajoene. a garlic derived compound, on themurinc melanoma BKiFlO cells: possiblerole of caspase-3 and the alpha(4)beta(I)integrin. Cancer Lett. 2t)()4 Mar3I:20f.(l):35-41.

I6.Tilli CM, Stavast-Kooy AJ. Vuerstaek JD.et al. The garlic-derived organosulfurcomponent ajoene decreases basal cellcarcinoma tumor size by inducing apopto-sis. Arch Dermatol Res. 2003Jul;29.'5(3): 117-23.

17. Xu B. Monsarrat B. Gairin JE, Girbal-Neuhauser E. Effect of ajoene. a naturalantitumor small molecule, on human 20Sprotcasnme activity in vitro and in humanleukemic HL60 cells. Fundam CHnPharnuuol 2004 Apr:18(2):17[-80.

18. Lu HK Sue CC. Yu CS. et ai. Diallyl disul-fide (DADS) induced apoptosis undergocaspase-3 activity in human bladder can-cer T24 cells. Food Chem Toxicol 2004Oct:42(IO):1543-52.

W. Wu CC. Chung JG. Tsai SJ. Yang JH.Sheen LY. Differential effects of allyl sul-fidcs from garlic essential oil on cell eyeicregulation in human liver tumor cells. FoodChem Ttmcol 2004 Dec:42(12);1937-47.

20. Sengupta A. Ghosh S. Bhatiaeharjee S.Das S. Indian food ingredients and cancerprevention - an experimental evaluation ofanticarcinogenie effects of garlic in ratcolon. A.tiiin Pac J Cancer t*rev. 2004Apr:5(2):126-32.

21. Zlotogorski HA, Liltner M. Potentialrisks, adverse effects and drug interactionsassociated with herbal medicine in dentalpatients. Refuat Hapeh Vehaslunayim. 2004Apr:2!(2):25-4L97.

22. Cioeon JO, Ciocon DG. Galindo DJ.Dietary supplements in primary care.Botanicals can affect surgical outcomes andfollow-up. Geriatrics. 2004 Sep;59(9):20-4.

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