Origin
Allium sativum (referred to as Garlic from here onwards) is highly abundant with a range of cultivation and medicinal practices spanning Mexico, Ethiopia, British Isles and Europe (Bekalo et al, 2009; Carrió et al, 2012; Estrada et al, 2007).
Identification
It is terate with small flat leaves, no flowers, pink-greenish white bulbils, reaching up to 1m tall (Stace, 2010).
Growing Conditions
Garlic requires lots of water and clay-loam soil. It is vegetatively propagated by planting its cloves in Autumn for harvest in early Summer, with leaf visible from March-April and leaf growth May-June (Rizzalli et al, 2002).
Compounds and composition
Compounds that contain sulphur and phenol are responsible for medicinal properties A majority of garlic is water, hence the high number of water-soluble sulphur-containing compounds with some lipid soluble. Phenolic compounds, responsible for anti-oxidant properties, are lipid soluble (Melo et al, 2011).
Extract preparation
Garlic has been used for medicinal purposes raw; as a powder; in tablets; as acetone extract; or several oil-based extracts, including oil of steam-distilled garlic, oil of oil-macerated garlic and oil of ether-extracted garlic (Rahman and Lowe, 2006 Macan et al, 2006).
A simple Ethanolic based extract:
- Place 10g dried sample in 50ml ethanol
- Concentrate the mixture in a Soxhlet (dehydration system) for 30 minutes
- Re-dissolve in 5 ml ethanol
A simple water based extract:
- Place 10 g dried sample in 50 ml distilled water
- Boil for 15 minutes, stirring constantly
- Filter, centrifuge (spin) and re-filter
- Reduce the volume to 5 ml by boiling
Medicinal uses
The medicinal use of garlic dates back thousands of years, but there was little scientific support of its therapeutic and pharmacologic properties until recently (Yeh andLiu,2001).
They possess anti-microbial, anti-cancer and anti-oxidative properties, with specific benefits for those suffering diabetes and cardiovascular problems (Benavides et al, 2007; Rahman and Lowe, 2006; El-Sayyad et al, 2010; Wong, 2010; Zhang and Zhang, 2012).
- Reducing Oxidative Stress
Garlic is capable of reducing oxidative stress by 2 mechanisms: improving the body’s natural anti-oxidant defenses, and by “picking up” the free radicals responsible for oxidative stress. Cancer, high cholesterol, immune deficiencies and aging have been linked to oxidative stress (El-Sayyad et al, 2010; Sekhar et al, 2011; Stranahan et al, 2011).
Glutathione and superoxide dismutase are common endogenous intracellular antioxidants that scavenge oxidants (Chen et al, 2011; Stranahan et al, 2011) Aged Garlic Extract prevents the depletion of intracellular glutathione and increases the activity of superoxide dismutase (Rahman and Lowe, 2006). Evidence of the antioxidant activity reversing the negative effects of hypercholesterol is present following oral administration to rats (El-Sayyad et al, 2010).
- Cardiovascular benefits
Garlic has a high profile for its benefits for those at risk of cardiovascular disease, by removing or reducing the factors associated with increased risk: raised serum total cholesterol and LDL, an increase in LDL oxidation and platelet aggregation; and reducing hypertension (Rahman and Lowe, 2006). It is suggested that the sulphur compounds in Garlic are converted into hydrogen sulphide, an endogenous cardio-protective vascular cell signalling molecule (Benavides et al, 2007). Hydrophilic and hydrophobic compounds found in garlic also inhibit cholesterol synthesis, shown by a 7% reduction in total cholesterol in the plasma of men with hypercholesterolemia (Yeh andLiu,2001). These effects are achievable through the consumption of raw garlic and inclusion in the diet.
- Diabetes
Methanol extracts of garlic have been found to prevent
Weight loss, decreased plasma glucose level, hyperalgesia, TBARS, suboptimal serum nitrite and GSH levels are complications of diabetes. These have been improved by the administration of methanol extracts of garlic to mice (Bhanot et al, 2010)., and shows promise for future use in humans.
- Additional medicinal applications
Additional medicinal applications for Garlic are: maintaining healthy liver function; treating respiratory problems, catarrh and fibrinolysis; inhibiting platelet aggregation; and improving circulation (Benavides et al, 2007; El-Sayyad et al, 2010; De et al, 2010; Rahman and Lowe, 2006; Raghu et al, 2012).
Garlic oil and diallyl disulfide reverse the negative effects of fatty deposits in the liver by reducing the quantity of triglycerides and cholesterol, as exhibited in rabbits. Human hepatitis patients given garlic oil also benefitted from normalized serum aminotransferease levels and liver antioxidant enzymes. (Lee et al, 2012; Raghu et al, 2012) Patients diagnosed with hepatopulmonary syndrome, also known as shortness of breath, improved with oral supplementation (De et al, 2010).
Disclaimer: This article is for research purposes only and although research supports the benefits of garlic, if you have a serious health concern please consult your doctor.
Reference list: If you would the reference list for these citations please ask.
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