Allicin: health benefits, how to extract it and more
This article aims to better understand the formation of allicin, this molecule of garlic, its main therapeutic activities and the mechanisms of its action
Natural allicin formation
Allicin is an active ingredient in freshly cut garlic. It comes from the enzymatic transformation of two components present in garlic: alliin and an enzyme alliinase. By crushing a raw garlic clove, alliin and alliinase combine to form allicin.
This transformation takes place in seconds. The allicin molecule thus formed is very volatile and has a very short lifespan. It has antimicrobial, antifungal, antiparasitic and antifungal activities.
A remarkable point is that alliin and alliinase are found in separate compartments in garlic. Alliin is located in the cytoplasm and alliinase in the vacuoles of the cell.
Thus this unique organization would be conceived as a possible defence mechanism against microbial pathogens in the soil. The invasion of garlic cloves by fungi and other soil pathogens begins by destroying the membrane that surrounds the compartments that contain the enzyme alliinase and the substrate alliin. This causes the interaction between alliin and alliinase which produces allicin and which in turn inactivates the invader.
The reactive allicin molecules produced have a very short half-life because they react with a lot of surrounding proteins, including the enzyme alliinase, transforming it into an almost suicidal enzyme.
This highly efficient organization ensures that the defence mechanism is activated only in a small place and for a short period of time, thus preserving the rest of the alliin and alliinase in their respective compartments and thus remaining available in case new microbial attacks.
In addition, the massive generation of allicin could be toxic to plant tissue and enzymes. However, its production being of short duration and is limited to the zone where the microbial attack takes place, the risk of damaging the plant is minimized.
The main activities of allicin
1 – Antimicrobial
Antimicrobial activity against a broad spectrum of gram-negative gram-positive bacteria. (Gram stains make it possible to identify the type of bacteria according to the existence or not of cell membranes)
2- Antifungal properties
Antifungal activity especially against candida albican, yeasts or microscopic fungi which, having become pathogenic, cause candidiasis, a fungal infection in the digestive and gynaecological mucous membranes. Allicin prevents the formation of mycotoxin. But the mechanism itself is still unknown.
3 – Antiparasitic properties
Antiparasitic activity in particular against protozoan parasites such as Entamoeba histolytica, a pathogenic amoeba causing dysentery and amebiasis or Giardia lamblia, the parasite causing diarrhoea in particular.
A condensation product of allicin, ajoene, (produced when the allicin is in aqueous solution) appears to have more antiviral activity in general than allicin itself.
In addition to this, other activities of allicin have been tested: It appears to have strong antioxidant activity. It lowers cholesterol levels. It inhibits the promotion of cancer and lowers eye pressure. We will treat in specific articles these particular effects studied in current research.
The mechanisms of action of an ally in
A better understanding of the biological roles and the pathological consequences of enzymes dependent on thiol (an organic compound containing sulfur and hydrogen) has emerged in recent years, and considerable progress has been made in the identification and delimitation of enzymes called cysteine proteases (amino acid containing a thiol group).
We now know that these enzymes are involved in a wide variety of disease processes, from cardiovascular, inflammatory, viral and immunological disorders to cancer.
Role of allicin
One of the main mechanisms involved in the antibiotic effect is the inhibition of these thiol-containing enzymes in microorganisms by the rapid reaction of thiosulfinates (such as allicin) with thiol groups.
The mechanism of action of pure allicin molecules with thiol groups has been studied in more detail and has confirmed the ability of allicin to react with a thiol compound (L-cysteine) to form a thiol product whose presence has been proven by nuclear magnetic resonance and mass spectrometry.
It seems reasonable to conclude that the broad spectrum of antimicrobial effects of allicin is due to multiple inhibitory effects on various thiol enzyme systems.
The effect of allicin can be viewed at different levels. Certain enzymes such as thiol proteases, which cause serious damage to host tissue, can be inhibited at lower concentrations.
At low concentrations, inhibition of these enzymes may not be fatal, but sufficient to block the virulence of the microbe. At slightly higher concentrations other enzymes may be affected and even partial inhibition of these enzymes could be fatal for the microorganism.
The wide range of allicin activities presented in this paper shows that this molecule is a leading candidate for therapeutic use.
Unfortunately, until now pharmaceutical companies have not been interested in the development of this antimicrobial molecule by investing and carrying out the necessary clinical trials before its commercialization. The reason for this unfortunate situation is simple: no patent can be submitted because the allicin molecule has long since fallen into the public domain. It is not the first time that economic considerations will prevent a natural compound with astonishing medicinal properties from reaching patients who could benefit from it…