phytotherapy

Properties of garlic - Phytotherapy

By Dr. Rita Fabbri

Garlic is a plant cultivated since ancient times. Linnaeus indicates Sicily as the homeland of the plant. Kunth means Egypt. Some authors state that the only country where garlic was found in the wild in a certain way is China. Other researchers claim to have found it spontaneous in India.

Today garlic is grown on all continents and is mainly known for culinary use. In Italy it is mainly cultivated in Campania, Sicily, Veneto and Emilia-Romagna (noteworthy is the Garlic of Voghiera, in the province of Ferrara, due to its specific genetic identity). The etymology of the botanical name derives from the Celtic word "all" meaning burning, with an allusion to flavor, and from the Latin "sativum" which means "that can be sown". Historical documents and popular beliefs (such as the alleged ability to keep vampires away) are a testament to the power of Garlic

Botanical name: Allium sativum L.

Family: Liliaceae

Parts used: bulbils

Botanical description

The garlic is a perennial herbaceous plant, cultivated as an annual. The true organs of propagation are the cloves or bulbils, which in groups of 5-20 form the bulb or head or head. This is wrapped in a series of leaves called sterile tunics with a protective function.

Garlic bulbs must be kept in a cool and ventilated place in crates or hung in the typical "reste".

Chemical composition

Sulfur compounds such as allicin, ajoeni, vinilditiine, thiosulfinates, diallylsulfides.

In the whole bulb sulfur compounds are mainly represented by alliin; when the bulb is ground, the ezyme is released, which quickly transforms the alliin into the respective sulfenic acid (responsible for the characteristic smell of garlic); subsequently, by self-condensation, thiosulfinates such as allicin are formed.

The enzyme allinase is inactivated by heat and this explains why cooked garlic gives off less odor than raw garlic and has less pharmacological activity.

Therapeutic indications

Garlic has a long tradition of use. Sanskrit documents testify to the use of Garlic 5000 years ago. Hippocrates, Aristotle and Pliny mention numerous therapeutic uses of garlic. It is frequently mentioned in Egyptian, Chinese, ayurvetic medicine. Garlic has been the subject of numerous pharmacological and clinical studies even in recent years.

The main pharmacological activities of Garlic can be summarized as follows:

  • Hypolipidemic and antiatherogenic activity
  • Anti-platelet aggregation action
  • Antihypertensive activity
  • Antibacterial and antifungal action
  • Antioxidant action

Therefore the main therapeutic indications are:

  • Prophylaxis of atherosclerosis
  • Hypertension
  • Hypertriglyceridemia / Hypercholesterolemia

Hypolipidemic and anti-atherogenic activity : very interesting are the clinical data concerning the use of garlic in the prevention of atherosclerotic disease and in the treatment of hyperlipidemia, not sufficiently corrected by diet alone. Garlic is believed to inhibit cholesterol synthesis by inhibiting hydroxymethyl-glutaryl-CoA reductase with a mechanism of action similar to that of statins. It seems that the effectiveness of the garlic can be enhanced by the simultaneous administration of plants able to sequester the bile salts in the intestine (for example the Guggul). Other authors claim that garlic inhibits the absorption of food lipids. Finally, at the hepatic level the Garlic seems to inhibit acetyl-CoA-synthetase, another enzyme involved in lipid biosynthesis.

The hypolipidemic activity is perhaps more important from the qualitative than quantitative point of view, in fact the garlic prevents the oxidation of LDL, thus reducing the risk of formation and progression of atherosclerotic plaques. We can therefore state that Garlic, especially after prolonged and continuous use, exerts a generic protective effect on the cardiovascular level.

Antihypertensive activity : the hypotensive effect of garlic has been studied by various authors but the mechanism of action has not been definitively specified. Certainly we have a peripheral vasodilation mediated by the inhibition of adenosine deaminase at the endothelium of the vessel, therefore an enhancement of the myorelaxant action of endogenous adenosine. Recently it has been shown that garlic also has a diuretic activity that would justify the hypotensive effect. Perhaps also an ACE-inhibitory action (inhibition of angiotensin-converting enzyme) and a calcium-antagonist activity could explain the moderate antihypertensive effect in hypertensive patients.

Antiplatelet platelet action : Garlic plays an anti-platelet aggregation action: the effect is mediated by the inhibition of the synthesis of proaggregating eicosanoids, in particular the thromboxane B2. The anti-aggregating action could also be due to the fact that the Garlic limits the intra-platelet mobilization of calcium, activates the NO-synthase of platelets and controls its ability to bind fibrinogen.

Antibacterial and antifungal action : Garlic is also used in upper respiratory tract infections and catarrhal diseases. It has a good activity against Helycobacter pilori responsible for some forms of gastroduodenal ulcer. Good efficacy also in some forms of mycosis of the foot and ear.

Also known in popular medicine is the anthelmintic action of garlic in intestinal infestations from roundworms and pinworms.

Finally, garlic has important immunostimulant and anticancer properties, confirming the epidemiological evidence that high consumption of garlic is associated with a reduction in the risk of several cancers. For example, in China a comparative study on the population of different regions showed that deaths from stomach cancer are significantly lower where the consumption of garlic is high compared to regions with lower consumption of garlic. Human studies have shown that garlic inhibits the formation of nitrosamines (powerful carcinogenic compounds that are formed during digestion).

dosage

The dosage of commercial garlic-based products should provide a daily dose of at least 10 mg of alliin or an allicin potential of 4, 000 µg. This quantity is roughly equal to a slice (4 g) of fresh garlic.

Contraindications, special warnings and appropriate precautions for use, undesirable effects

No known contraindications. Caution is recommended in the pre-operative state (the use of garlic-based preparations should be suspended at least a couple of weeks before surgery or biopsy tests). To be used with caution in subjects suffering from peptic ulcer or gastritis. There are rare cases of gastrointestinal irritation in sensitive individuals. There are no reasons to exclude the use of garlic in pregnancy and lactation, however some volatile components of garlic containing sulfur pass into breast milk, changing its taste.

Altering the smell of breath is the most commonly found undesirable effect for garlic.

It should be avoided in combination with anticoagulant and antiplatelet agents, and with some antiretroviral drugs in HIV therapy.

Garlic has a high safety profile as can easily be guessed from the long tradition of culinary use.