in vivoagainstH.pylori, pneumococci,Can-
dida,Aspergillus, and dermatophytes) with the
hydroalcoholic extract reportedly being much
more potent than the essential oil;2,15,28,36–48
a pilot study in 10 AIDS patients found that
a garlic extract produced an improved helper:
suppresser ratio in natural killer cell activity,
with a concurrent improvement in AIDS-
related conditions, including diarrhea, genital
herpes, candidiasis, and pansinusitis with re-
current fever;49,50garlic also has larvicidal,
insecticidal, and amebicidal activities (e.g.,
antigiardial and antitrypanosomal);48,51–53(iv)
anti-inflammatory (inhibition of COX and
prostaglandin synthesis);54–57 (v) antitumor
activities against various tumormodels in mice
and rats;58–61(vi) hypoglycemic activities in
rabbits and rats;21,62–64(vii) antioxidant/anti-
hepatotoxic/radioprotective activity in rats
(mainly due toS-allyl cysteine);65–67garlic
was recently reported to be effective in the
treatment of hepatopulmonary syndrome.^68
Garlic also lowers blood viscosity; improves
microcirculation; with expectorant, diaphoret-
ic, and diuretic properties,amongothers (ESCOP
2; JIANGSU; LIST AND HO€RHAMMER; MARTIN-
DALE).^69 It has recently been reported
to reduce osteoporosis and to possess
immunomodulatory and spermicidal activi-
ties.70–72
Antithrombotic activity has been attributed
to various fractions of garlic. Ajoene has
antithrombotic activity triggered by inhibiting
exposure of fibrinogen receptors on platelet
membranes. Diallyl sulfide and methyl allyl
sulfide, claimed responsible for the antithrom-
botic activity, were found to be inactive in
inhibiting platelet aggregation.^73 However, a
recent study attributes higher thrombocyte
aggregation-inhibiting potential to chloro-
form fractions of thiosulfinate than to the
ajoenes.^3 The platelet aggregation-inhibiting
activity, as well as possible antiplaque ef-
fect,^74 may be responsible for the potential
utility of garlic as a useful protective agent in
atherosclerosis, coronary thrombosis, and
stroke (TYLER1).^49
The volatile sulfur compounds (especially
allicin, diallyl disulfide, and diallyl trisulfide)
are generally considered to be responsible for
much of garlic’s pharmacological activities
(e.g., hypoglycemic, hypocholesterolemic,
antimicrobial, insecticidal, and larvicid-
al).23,45,48,53,63Allicin, believed to be the most
important biologically active compound in
garlic, is primarily responsible for its antibi-
otic and antimutagenic effects.75,76
One study found that thiosulfinates (e.g.,
allicin) were not formed below pH 3.6, thus
alliinase is completely and irreversibly inhib-
ited by stomach acid. A second (unidentified)
enzyme, in addition to alliinase is involved
in thiosulfinate formation. A stomach acid-
resistant coating on garlic powder tablets is
necessary for thiosulfinate release, which if
prepared carefully can release amounts of
total thiosulfinates similar to whole garlic
cloves.^77
Garlic oil acts as a gastrointestinal smooth
muscle relaxant, suggested for further re-
search in patients with hypermotile intestinal
disorders.^78TOXICOLOGYAllergic contact dermatitis due to garlic has
been reported (MARTINDALE).USESMedicinal, Pharmaceutical, and Cosmetic.
Strong popular interest has made garlic pre-
parations the best-selling over-the-counter
drugs in Germany, with sales topping $250
million per year in Europe.^79Food. Fresh garlic and powdered garlic are
widely used as domestic spices. Garlic oil is
extensively used as a flavor ingredient in most
food products, including nonalcoholic bev-
erages, frozen dairy desserts, candy, baked
goods, gelatins and puddings, condiments and
relishes, meat and meat products, fats and oils,
snack foods, and gravies, with highest average
maximum use levels generally much below
0.003% (34.4 ppm).Garlic 309