Introduction
In order to find new and better treatment for many diseases, it is important to continuously
search for new drugs. This can be done in various ways, one of which is to search in Nature.
Compounds from nature are biologically and ecologically based and produced as a defence
system for the plant or living organism in question.
The discovery of new drugs from natural compounds has been of significant importance in the
past and obviously will continue to be just as important if not more, in the future. The
significance is supported by looking at the latest review in the industry revealing that 32
natural products or their analogs are in clinical use or clinical trials as anti-tumor drugs.
Another proof of the importance of natural compounds is that between 1983 and 1994, 39%
of new approved drugs were of natural origin (web article #1). Some examples of effective
natural drugs are Morphine, Quinine and the head of this essay; Allicin (from garlic).
There are different ways of selecting and collecting the plant that is going to be investigated.
One method is to completely collect all the plants in a specific area; the random method.
Another approach is to collect plant families which are known to have or to be rich in
biologically active compounds (web article #1). The method of using the local people´s
knowledge ( the ethnobotanical approach) about the medical usage of the plants could be
very interesting since many of these people are believed to have the ability of communication
and integration with plants. These so called Shamans meet the spirit of the plant and get
advice in healing and curing different diseases (Isdamen).
Garlic
Allium Sativum, or garlic, has like other plants a defense system composed of as many
different components as the human immune system. Researchers have been able to see that
garlic works at the molecular level using Allicin which is the main biologically active
component. Allicin is created when garlic is crushed and protects it from soil parasites and
fungi (Allicin.com). It is also responsible for the pungent smell of which garlic is known for.
The appearence of garlic oil is colorless, light yellow or brownish-yellow. It is not soluble in
water but has a 95% solubility in alcohol and vegetable oils. It is preaperd in North Africa
(Egypt), Europe (Bulgaria, France and Germany), Asia (China and Japan) and America.
Garlic oil should be stored in cool, dark and airtight places (Shenet- Vitlök eterisk olja).
Pure Allicin can be stored for months without losing it’s effects, but naturally extracted Allicin
loses it’s effect within a few hours due to side reactions (Allicin- The Garlic Antibacterial).
Allicin is very volatile and unstable. Elements responsible for the breakdown of Allicin is air,
water and heat, e.g the human body temperature which converts the Allicin to polysulfides
which is responsible for the famous “day-after-garlic” odour consisiting mainly of diallyldisulfide.
Table 1 and figure 1 below gives a brief view in different types of garlic and their action
potentials.
Type of
supplement
Fresh garlic
source declared
on pack
Process to manufacture
supplement
Allicin
potential
Published
blinded
clinical data
Garlic Oil
No
Steam distillation
No
No
Aged Garlic
No
Aged over 2 years
No
Some
Garlic
Macerates
Garlic
powder
No
Crushed and dried
Some
No
Sometimes
Cloves chopped and
dried under pressure and
temperature control
Yes
(Stomach acid
protection
needed)
Yes
Allicin
powder
extract
No
Specialised patented
extraction process
produces allicin liquid
that is spray dried
Product is
allicin
Yes
Table 1: Types of garlic available in Healthfood Store Shelves (Allimax).
Figure 1: Garlic in different forms
Allicin chemistry from garlic
Allicin is chemically known as 2-propene-1-sulfinothioc acid S-2-propenyl ester; thio-2propene-1-sulfinic acid S-allyl ester (Allicin.com).
As mentioned previously, Allicin is the major medicinal compound in garlic which acts as an
antifungal and antibiotic compound. Allicin is not to be found naturally in garlic. Instead, the
garlic contains the amino-acid Alliin (se the structure in Figure 2).
Figure 2: Structure of Alliin (Garlic Central)
When garlic is damaged or crushed for any reason, alliin reacts with an enzyme called
allinase, which is found naturally in garlic, and the result of this reaction is the transformation
of alliin into Allicin. The structure of Allicin is shown in figure 3.
Figure 3: Structure of Allicin (Garlic Central)
As mentioned before, once Allicin breaks down, we have the formation of various diallyl
sulphides, most commonly diallyl disulphide as shown in figure 4:
Figure 4: Structure of Diallyl disulphide (Garlic Central)
Although this form of Allicin is not known to have the same anti-bacterial or anti-fungal
properties as Allicin itself, it is believed to still serve a medical function in regards to
cholesterol and circulation (Garlic Central).
How does Allicin work?
The biological activity of Allicin extracted from fresh garlic is thought to be related to a
combination of factors:
1. it’s antioxidant activity
2. modification of enzymes and proteins by attacking the SH-groups
3. rapid penetration into cells through the cell membranes
In laboratory studies, Allicin has shown a number of beneficial properties which together with
the bodies natural response to diseases can give a better result. The published laboratory
results about Allicin are:
• Enhances the activity of phagocytic cells
• Enhances the activity of natural killer cells
• Inhibits the growth of pathogenic micro-organisms
• Inhibits the growth of certain cancer cells
Recently it has been suggested that Allicin works through the reaction with L-cysteine (a
model thiol compound) to form S-allylmercaptocysteine. So the interactions with important
thiol-containing enzymes is Allicins main antimicrobial effect (Allimax).
Allimed™
Allimed™ is a cold aqueous extraction of Allicin, reported to be stable and have high activity,
in vitro, against Staphylococus aureus (MRSA) which is a methicillin resistant bacteria.
People with MRSA are known to have problems with closure for many chronic and acute
wounds and are therefore more susceptible to high levels of bacteria in tissues. A closure of
wounds in such patients can be due to secretion of toxins that can lead to local necrosis and
the delicate balance of critical healing progress mediators such as cytokines and proteases is
then disrupted. Allimed™ was therefore required to be tested on patients with MRSA because
of Allicins strong SH-modifying and antioxidant properties. Allicin reacts chemically with thiol
groups of various enzymes such as alcohol dehydrogenase, thioredoxin reductase and RNA
polymerase. The result of the tests is that Allicin seems to reduce the activity of extracellular
virulence factors because many of the patients were relieved from the symptoms before
MRSA was fully removed (Allimax).
Figure 4 a: Methicillin resistant Staphylococcus aureus with plain aqueous cream (Allimax).
Figure 4 b: Methicillin resistant Staphylococcus aureus with allicin cream added (Allimax cream)
showing a large zone of inhibition (Allimax).
Contradictions
A study in which participants consumed a certain amount of garlic cloves showed no detected
Allicin in neither blood nor urine samples. This lead to the conclusion that Allicin is not
bioavailable. It can be because of Allicins high reactivity and so its complete metabolisation in
liver. If Allicin did somehow make it to the blood system, it was shown that it would change
into other compounds within minutes and could even affect the bloods ability to carry oxygen
(Allicin.com).
Another contradiction is that it is not Allicin itself which is responsible for garlic’s beneficial
properties since not much Allicin can be detected in the body or in other forms of garlic (e.g
cooked). So there must be compounds other than Allicin responsible for garlic’s reputation
(Allicin.com).
Garlic intake over the normal amounts can lead to an allergic reaction (Allimax).
Conclusion
There must be a reason why garlic has been eaten for so long because of it’s beneficial
health reputation. Although there is proof of Allicin’s action and lack of action, there is no
reason for us not to enjoy the taste of this wonderful root. If the day-after garlic smell is of the
same good quality as the taste, well that’s up to the surrounding company to decide...
Reference
 Shenet-Vitlök eterisk olja
www.shenet.se/ravaror/eovitlok.html
 Garlic Central
www.garlic-central.com/allicin-chemistry.html
 Allicin.com
www.allicin.com
 Allicin-The Garlic Antibacterial
www.garlic.mistral.co.uk/allicin.htm
 Isdamen
http://paranormal.se/topic/vaxt.html
 Allimax
www.allimax.us
 web article #1
http://scholar.lib.vt.edu/theses/available/etd-0712200016230006/unrestricted/thesis2.pdf