**5. Conclusion and recommendations**

From this review it is evident that garlic certainly has some medicinal properties. Various studies highlighted its cardio protective, antibiotic, anti-hypertensive and cholesterol lowering effects. Some evidence also points to its ability to lower the risk of developing cancer. Not all the research data are as clear and conclusive and certain remain ambigu‐ ous. Garlic appears to exert both positive and negative effects on the male reproductive system. Interestingly enough crude garlic (if taken in large amounts) shows the most detrimental and AGE garlic the most beneficial results. The most crucial factor in determin‐ ing the effects observed is possibly the manner in which the garlic was prepared as well as the amount that is being administered. Interestingly, large amounts are deemed to be

more detrimental. Some of the results found showed that the administration of garlic affected testicular function, histological properties and sperm quality [46, 48 & 51]. Hormone levels were subsequently also altered and an increase in testicular tissue apoptosis was recorded [51]. Furthermore crude garlic extracts and garlic juice showed to cause sperm immobilization (administered as 15g/100g and 30g/100g respectively) [51, 67, 68]. More research definitely needs to be performed on the effect of garlic on acrosome and DNA integrity of spermatozoa.

the majority of the antioxidant affects are from the AGE there are incidents where other preparations were used as an antibiotic/antioxidant. A lot of the mechanisms by which garlic acquired its medicinal properties have been specifically ascribed to this potent antioxidant action. It has the ability to stimulate immunological responsiveness and its modulation of prostanoids synthesis. The antioxidant properties of garlic have been studied extensively and it does have a beneficial role in the body. AGE is however more effective in removing free radicals and LDL cholesterol than other preparations of the garlic root, but that does not mean

Allicin, found in the garlic bulb, serves as a powerful antibiotic which aids the body in inhibiting the growth and reproduction of bacteria [63]. One milligram of allicin is equal to 15 standard units of penicillin [63]. Allicin attacks over 23 types of bacteria, such as staph and salmonella, 60 types of fungi and yeast and is also effective against 17 of the most dangerous fungi [64]. Another example of where allicin serves as a potent antibiotic is in the treatment of Streptolysin O (SLO). SLO is a powerful cytolytic toxin found in almost all group A streptococci. Treatment of SLO with Allicin completely neutralized the haemolytic activity of the bacteria, while the aqueous garlic extract inhibited it altogether [65]. From these results it can be deducted that garlic and its metabolites have antibiotic properties. Extracts of fresh garlic contain antioxidant phytochemicals that prevent oxidative

NO and H2S play major roles in the progression of diseases, both NO and H2S are considered to be important vasodilators. In a recent study both serum NO and H2S were measured in diabetic rats and it was shown that chronic administration of garlic normalised both gaseous molecules [26] and this decreased hypertension by inhibiting certain enzymes such as N

From this review it is evident that garlic certainly has some medicinal properties. Various studies highlighted its cardio protective, antibiotic, anti-hypertensive and cholesterol lowering effects. Some evidence also points to its ability to lower the risk of developing cancer. Not all the research data are as clear and conclusive and certain remain ambigu‐ ous. Garlic appears to exert both positive and negative effects on the male reproductive system. Interestingly enough crude garlic (if taken in large amounts) shows the most detrimental and AGE garlic the most beneficial results. The most crucial factor in determin‐ ing the effects observed is possibly the manner in which the garlic was prepared as well as the amount that is being administered. Interestingly, large amounts are deemed to be

the other preparations aren't important as well.

270 Antioxidant-Antidiabetic Agents and Human Health

omega-nitro-L-arginine-methyl-ester (L-NAME) [66].

**5. Conclusion and recommendations**

**4.2. Antibiotic properties**

damage.

**4.3. NO and H2S**

In general it can be said that garlic's therapeutic properties warrants further investigation in order to develop its full treatment potential as a phytotherapeutical agent impacting on human health and used for the treatment of various disease conditions. The specific mechanism of action also need to be identified as it can possible shed more light on and help with the development of more effective pharmacological agents. Additional human studies on AGE and its constituents are needed to elucidate their role in protecting human health, and molecular studies should be intensified to reveal the underlying mechanisms.


1Laboratory Report, Wakunaga Pharmaceutical, Hiroshima, Japan, October 1995. Courtesy of Wakunaga of America Company. Garlic products were purchased from stores, as in Freeman and Kodera 1995. Each analysis was performed three times.

<sup>2</sup>Antioxidant properties were measured by the ability of the various products to inhibit the emission of low level chem‐ iluminescence, in a liver microsomal fraction, initiated by t-butyl hydroperoxide (Imai et al. 1994). Inhibition (+) de‐ notes antioxidant activity, resulting from scavenging of reactive oxygen species (ROS) and reflected in the inhibition of light emission. Inhibition (-) denotes prooxidant activity of a product as reflected in an increased light emission, in‐ duced by increased ROS activity.

\*Table reproduced from ''Recent Advances on the Nutritional Benefits Accompanying the Use of Garlic as a Supple‐ ment" held November 15–17, 1998 in Newport Beach, CA. The conference was supported by educational grants from Pennsylvania State University, Wakunaga of America, Ltd. and the National Cancer Institute. The proceedings of this conference are published as a supplement to *The Journal of Nutrition 131:1010S–1015S, 2001*.

**Table 1.** Antioxidant effects of aged garlic extract (AGE) compared with other garlic supplements1\*

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**Figure 1.** Photomicrographs of sections of testes of albino rats having received 20% of their daily food as crude garlic for two months (subgroup B1) showing: (A) intraepithelial vacuoles of variable sizes (V). Sertoli cell nuclei () on the basal portion of the tubules. Primary spermatocyte nuclei either dividing normally (↑) or with condensed chromatin (↑↑). Some seminiferous tubules possess irregular basal lamina and are separated from each other. Interstitial tissue with Leydig cells (L), plasma cells (c) and lymphocytes (Y) (×200). (B) Giant cell (↑) formation and exfoliation in the lumen of the seminiferous tubules (×200). (Reproduced from Abdelmalik, 2011)
