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INFLUENCE OF A BUFFERED MATRIX AND PROTEIN UPON ALLICIN
BIOAVAILABILITY FROM A COMMERCIAL GARLIC POWDER
R. Falkenberg and H. Archibald, Nutra Products, Inc., Fairfield, CA (Introduced by Doug Kalman, MS, RD, FACN)
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| ABSTRACT |
The ability of garlic powders to produce significant amounts of
allicin upon disintegration in the stomach is unknown. We have
assessed allicin bioavailability after garlic ingestion using
breath analysis of allyl methyl sulfide (AMS), the primary allicin
metabolite. We compared the allicin bioavailability of a buffered
garlic product (BGz; Garli-Eze®, Nutra Products, Inc., Fairfield,
CA) to a non-buffered form (NBG), both delivered in nonenteric coated capsules containing 600 mg of garlic powder.
Two subjects were fed a high protein meal (HP) with water.
Fifteen minutes after they began the meal they were given 3
capsules of BGz. The impact of a low protein meal (LP) prior to
ingesting BGz or NBG capsules was also evaluated. Breath
was collected before capsule consumption and an additional 18
times over the next 32 h. AMS was analyzed and expressed as
area under the curve (AUC32 in ng-h/L). Percent allicin
bioavailability (%AB) was determined by comparison to the
AUC32 for consuming a known amount of allicin from crushed
raw garlic. Results are expressed as the mean of the two
subjects: AUC32: HP + BGz (1912), LP + BGz (2085), LP +
NBG (1162); %AB: HP + BGz (85%), LP + BGz (93%), LP +
NBG (51%). These data suggest that a buffered matrix
augments the delivery and/or bioavailability of allicin, which
also appears to operate independent of the buffering load of a
protein-rich meal. |
| RATIONALE |
| Garlic has been the subject of intense clinical research,
especially in relation to its hypolipidemic effects. The existing
evidence base yields equivocal data, which likely is due to both
substantial differences in study design and in the variable
chemoprofiles of each of the garlic preparations that have been
examined. This clinical evidence eclipses the number of clinical
pharmacologic investigations performed to date. This may
result from both the a priori assumption that any garlic
preparation that yields garlic’s primary bioactive, allicin, within
an in vitro system would do so in vivo, and the absence of
sufficiently specific and sensitive analytical methodologies.
Allicin is a biologically ephemeral molecule that is produced
only upon the crushing of garlic via the enzyme alliinase acting
upon its substrate, alliin. Within dietary supplements, however,
alliinase does not convert alliin to allicin until the dose form
disintegrates in the body, requiring the preservation of alliinase
activity throughout the manufacturing process as well as from
the acidic and hydrolytic conditions accompanying gut transit.
We have developed a novel composition that combines a
natural alkalizing matrix with a suitably processed garlic extract
(Garli-Eze®), designed to create a gut microenvironment
fostering de novo allicin production and bioavailability, and
obviating the need for enteric coating agents. We implemented
a validated in vivo method shown to assess allicin
bioavailability by capturing the breath evolution of the allicin
end metabolite, Allyl Methyl Sulfide (AMS) (1). |
| EXPERIMENTAL DESIGN |
Subjects
- Two persons for whom 100% allicin bioavailability response
had previously been determined after consumption of
homogenized fresh garlic containing known amounts of
allyl thiosulfinates (allicin and other thiosulfinates).
- Subject 1 (EM) = female, age 31, Ht. 5’5”, Wt. 145 lbs
- Subject 2 (LL) = male, age 59, Ht. 5’6’’, Wt. 140 lbs Supplementation/Meal Protocol
- Subject restrictions: 24 hours prior to dosing - no garlic or
onions or foods that commonly contain them in small
amounts, such as salsa, ketchup, soups, salad dressings.
- The subjects ate 2 different standardized breakfast meals
(8 am) on separate dates (min. 3 day washout):
- High protein meal (27 g protein): a tuna
sandwich (½ can, 3 oz., albacore tuna, 2 slices
whole wheat bread, fat-free Miracle Whip) and
4 oz. of 2% milk.
- Low protein meal (5 g protein): 2 slices of white
bread toast (w/butter and jam), a banana, and
6 oz. water.
- At 15 min after starting to eat the meal (about 5-7 min after
finishing the meal), each subject consumed 3 Garli-Eze
capsules (2,200 mg garlic extract) or 3 capsules of a nonalkalized/
non-buffered version of the same garlic extract
(1,800 mg of garlic extract), with water (4-6 oz.).
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| METHODS AND PROCEDURES |
Allyl thiosulfinate potential analysis of garlic extract
- This value was necessary in order to determine % allicin
bioavailability. This is the maximum amount of allicin and
other allyl thiosulfinates that can be formed; specifically
when the capsule contents are dispersed in aqueous
solution, provided the final pH is in the optimum range for
alliinase activity (pH 4.5-7). For non-buffered garlic powder,
dispersion in water gave a pH in the optimum range. For
Garli-Eze, it was necessary to disperse the powder in 0.015
N HCl, as dispersion in water gave a final pH of 8.7, which
caused a considerable reduction in thiosulfinates. Allicin
and other thiosulfinates were analyzed using C18-HPLC
upon elution with methanol/water (1:1) at 240 nm (2).
Breath collection and analysis
- Subjects exhaled into 1-liter breath bags just before
consuming the meal and capsules, then hourly for 8 hours,
then every two hours (except during sleep) until 32 hours
after capsule consumption. Each subject was given 4
breath bags to take home for breaths at 10, 12, 14, and 22
hours after consumption. Non-leak bags were used for
overnight breaths.
- Breath samples were analyzed for AMS using a sensitive,
sulfur-selective detector (GC-PFPD) (1). The area under
the 32-hour concentration curve (AUC32) was determined
by a computer program. Bioavailability, relative to
consumption of a known amount of allicin from raw,
crushed garlic, was expressed as a percentage.
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| DATA ANALYSIS |
- Data are presented as the changes from baseline for each
subject, LL and EM, or as the mean of these 2 subjects.
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| RESULTS |
- The protein content of the meal appeared to have no
impact upon mean allicin bioavailability of Garli-Eze, being
85.0% for the high protein meal and 92.5% for the low
protein meal (top right image).
- Under the low protein meal conditions the mean allicin
bioavailability of the non-alkalized/non-buffered garlic
composition was 51.0% (middle right image).
- Neither subject reported gastrointestinal discomfort or other
adverse effects in association with the ingestion of either
garlic composition.
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| CONCLUSIONS |
- Under the conditions employed in this pilot, proof of
concept study, the Garli-Eze alkalized/buffered garlic
composition demonstrated bioavailability comparable to a
similar amount of allicin released from raw, crushed garlic
(bottom right image).
- The protein content of the test meals appeared to have
negligible impact upon allicin bioavailability.
- Allicin bioavailability of the non-alkalized garlic composition,
which lacked enteric coating, was unexpectedly high.
- Further investigations examining the pharmacokinetics and
pharmacodynamics of Garli-Eze are warranted.
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| REFERENCES |
- Lawson LD and Wang ZJ. Allicin and allicin-derived garlic
compounds increase breath acetone through allyl methyl
sulfide: use in measuring allicin bioavailability. J Agric Food
Chem 2005;53:1974-83.
- Lawson LD, Wood SG, Hughes BG. HPLC analysis of allicin
and other thiosulfinates in garlic clove homogenates. Planta
Med 1991;57:263-70.
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| Click on graphs to view a larger image: |
Low vs. High Protein Meal |
Buffered vs. Non-Buffered Garlic Powder |
Fresh Garlic vs. Garli-eze |
| PDF Version |
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