**2. Garlic: Overview and properties**

Allium sativum, or commonly known as garlic, is a vegetable species that can be classified as either a food or a medicinal herb. It is a widely used plant product that is cultivated all over the world. Garlic falls into a family of *Amaryllidaceae* or the genus Allium. Its closest relatives in the onion genus include the onion, shallot, leek, rakkyo and chive [4].

**•** AGE is obtained by placing garlic cloves in ethanol for a minimum of 20 months at room temperature. This reduces the concentration of allicin [13]. Which could reduce the medic‐

Garlic and Its Effects on Health with Special Reference to the Reproductive System

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**•** Garlic oil is obtained through a complex steaming and distillation process and is used in

The preparation of the garlic bulb is probably the most important factor in its effectiveness. Fresh garlic is often described as the best preparation to use to get superlative medicinal value out of the herb. Dried or cooked garlic often loses its potency because the amount of allicin present is significantly decreased in the cooking process [3]. Although the active ingredient in garlic is said to be unknown there is a lot of speculation around allicin as being the main constitutive/candidate [3]. More studies on sulphur are currently being done as this could also play a significant role, especially in organically grown garlic. Other studies state that the active ingredients are more directly associated with sulphur-containing amino acids, such as allicin, S-allylcysteine (SAC), S-allylmercaptocysteine (SAMC) S-methylcysteine, diallyl disulphide

Allicin is a very unstable molecule and breaks down very easily. This is why it is recommended to eat fresh garlic as it contains the highest amount of allicin. It is also the reason for the strong odour that garlic possesses. The more prominent this odour is the higher levels of allicin and beneficial values the bulb is said to have [15]. Due to this instability medical companies have now started to develop garlic supplements that contain Alliin - a stable precursor to allicin. It is only released upon digestion meaning the body will have the added benefit of having a sufficient amount of the favourable metabolite along with the safer more stable option [15].

The preparation of the garlic is of vital importance and studies have shown that each prepa‐ ration has its own beneficial effects and more importantly its own threshold to when it starts becoming detrimental to the body. 2-5g of RG and 10-15g of boiled garlic provide beneficial effects with regard to prevent cancer development [16]. Likewise a certain amount of garlic supplementation would be beneficial in the male reproductive system. Unfortunately this

Garlic has been considered as a disease preventative food and its effects on the human health have been studied. Garlic infused medicine is on the increase due to the proposed beneficial effects on human health. The effects of garlic on both plant and animal models is best known for its ability to decrease the amount of lipids or free fatty acids, as well as its anti-atherogenic

Garlic supplements are now also being widely developed and recent studies have shown just that by mimicking the effect garlic has on the body. Allium products have the potential to reduce the risk of developing cancer or the potential to decrease the risk factors associated

inal properties of garlic as allicin is said to play a significant role.

cooking or as medicinal oil.

and sulfoxides [14].

amount is still unknown.

effects in both models [8].

**3. Garlic and human health**

The bulbs are mainly composed of water (approximately 84.09%), organic matter (13.38%) and inorganic matter (1.53%). The leaves consist of more or less the same components with slightly different ratios (water 87.14%, organic matter 11.27% and inorganic matter 1.59%) [5, 6].

The organic matter is mostly carbohydrates while the inorganic matter is compounds such as sulphur and iron. The large number of sulfur compounds contributes to the smell and taste of garlic. Allicin has been found to be the compound most responsible for the "hot" sensation of raw garlic (RG) [7]. Allicin, along with its decomposition products diallyl disulphide and diallyl trisulphide, are major contributors to the characteristic odour of garlic, while other allicin-derived compounds, such as vinyldithiins and ajoene show beneficial *in vitro* biological activity [4].

Despite having a minimal amount of ions and other compounds, those that are present play a very important role in the composition and overall beneficial effects that garlic potentially possesses [8].

When crushed, *Allium sativum* yields allicin, an antibiotic [9] and antifungal compound (phytoncide) discovered by Cavallito and colleagues in 1944. Fresh or crushed garlic also has enzymes, B vitamins, proteins, minerals, saponins, flavonoids, and Maillard reaction products. Furthermore, a phytoalexin (allixin) was found, a nonsulfur compound with a γ-pyrone skeleton structure with antioxidant effects, antimicrobial effect [10]antitumor promoting effects [11], inhibition of aflatoxin B2 DNA binding and neurotrophic effects [11].

There are different variants of the garlic root and each has its own properties that aid with good health. The white (natural) and black (fermented) garlic are just derivatives of how it is prepared, although each has its own unique effects. The white garlic is said to have medicinal properties while the black fermented garlic is more commonly used for cooking. Garlic can further be divided into two main subspecies being Ophioscorodon or hard necked garlic and Sativum or soft necked garlic [12]. Garlic can often be found in 4 forms namely; RG homoge‐ nate, garlic powder, aged garlic extract (AGE) and garlic oil.


The preparation of the garlic bulb is probably the most important factor in its effectiveness. Fresh garlic is often described as the best preparation to use to get superlative medicinal value out of the herb. Dried or cooked garlic often loses its potency because the amount of allicin present is significantly decreased in the cooking process [3]. Although the active ingredient in garlic is said to be unknown there is a lot of speculation around allicin as being the main constitutive/candidate [3]. More studies on sulphur are currently being done as this could also play a significant role, especially in organically grown garlic. Other studies state that the active ingredients are more directly associated with sulphur-containing amino acids, such as allicin, S-allylcysteine (SAC), S-allylmercaptocysteine (SAMC) S-methylcysteine, diallyl disulphide and sulfoxides [14].

Allicin is a very unstable molecule and breaks down very easily. This is why it is recommended to eat fresh garlic as it contains the highest amount of allicin. It is also the reason for the strong odour that garlic possesses. The more prominent this odour is the higher levels of allicin and beneficial values the bulb is said to have [15]. Due to this instability medical companies have now started to develop garlic supplements that contain Alliin - a stable precursor to allicin. It is only released upon digestion meaning the body will have the added benefit of having a sufficient amount of the favourable metabolite along with the safer more stable option [15].

The preparation of the garlic is of vital importance and studies have shown that each prepa‐ ration has its own beneficial effects and more importantly its own threshold to when it starts becoming detrimental to the body. 2-5g of RG and 10-15g of boiled garlic provide beneficial effects with regard to prevent cancer development [16]. Likewise a certain amount of garlic supplementation would be beneficial in the male reproductive system. Unfortunately this amount is still unknown.
