Botanical family: Liliaceae.
Source- http://foodsanddiseases.com/onion-health-benefits-medicinal-uses-and-properties
Onion is a bulb of the onion plant, Allium cepa L., of the botanical family liliaceae. It is formed from an underground thickening of the stalk. Onion is one of the nature’s most endowed food when it comes to healing. This has been found since during the ancient times of the Israelites, about 3500 years ago. They found it to be very effective in the treatment and prevention of respiratory disorders.

PROPERTIES OF ONION
The following are some of its composition:

• Carbohydrates are present in about 6.85%.

• Proteins are also present in about 1.16%.

• Contains very little fat content of about 0.16%.

• Contains almost all vitamins, only with the exception of vitamin B12, although they are all in small amounts.

• Minerals are also present in significant quantities, among which potassium stands out. Trace elements like sulphur are also present.

• Flavonoids are an important non-nutritive component present in the onion. An example is quercetin. In general, flavonoids help improve blood circulation, stops the oxidation of low-density lipoproteins, a type of fat in the blood that causes arteriosclerosis, and blood clot.

• Essential oil also forms part of the non-nutritive components. They are composed of several substances, amongst which thiosulfinate and allyl disulfide stands out. Essential oils are responsible for the onions typical odour and volatility.

• Vegetable fiber is also present in onion. They have been attributed to onion’s anti-diabetic action, and its diminishing effect on the absorption of cholesterol.

• Enzymes are present in onion in rich amounts. Some of these enzymes present includes diastase and oxidase, which both have an invigorating effect on the digestive process (i.e they help make digestion more easy and efficient).

• Glycoquine, a vegetable hormone is present in onion. It helps reduce the blood’s glucose level. Thus, explaining onion’s anti-diabetic action.
HEALTH BENEFITS / MEDICINAL USES OF ONION
After reading the above properties of onion, you will be able to grasp some of its medicinal applications. Its medicinal properties are mainly attributed to its non-nutritive components (the essential oil, vegetable fiber, glycoquine, enzymes and so on). These substances are said to be responsible for most the onion’s medicinal properties such as its anti-asthmatic, diuretic, antibiotic, and anticarcinogenic effects. Below, are some of the onion’s well known medicinal indications:

• Bronchial asthma – Studies have proven that thiosulfinate, one of the onion’s essential oil, is effective in stopping bronchial allergic reactions to asthma. This substance causes the dilation of the bronchial passage. The studies have also concluded that, the anti-allergenic effect and the dilating effect of the bronchial passage ways of the onion, makes the eating of raw onion effective in cases of bronchial asthma.

• Cancer – studies conducted by the National Cancer Institute of United States, found that those who eat more onions have a much lower risk of developing cancer. It shows that the onion has the capacity to neutralize carcinogens ( substances that can cause cancer http://foodsanddiseases.com/cancer ), and also prevent the development of tumor cells.

• Diabetes - The consumption of onion helps reduce the blood glucose level. This is due to the presence of glycoquine. As we already know, diabetes is caused due to an increased level of glucose in the blood, therefore, the consumption of onion is highly indicated for the diabetics.

• Coronary heart disease and arteriosclerosis - Onion help prevent arteriosclerosis and thrombosis, thus, improving blood circulation. Evidences have also shown those who eat onions have a lower risk of dying from a heart attack. We can therefore conclude that, ‘regular consumption of onions in any form, be it raw, boiled, or baked, helps: ◊ improve blood circulation ◊ prevents arteriosclerosis, and ◊ reduces the risk of suffering from heart attack.

• Kidney disorders - the alkalizing effect of onion explains this. It facilitates the elimination of waste products from the body. This elimination can be in the form of an increase in urine production. Thus, those suffering from kidney related disorder such as kidney stones and renal failure, should increase the consumption of onions in their diets.

• liver disorders- Onions are highly recommended in cases of liver disorders as they help stimulate the detoxifying effect of the liver. They are highly indicated in cases of hepatic failure.

• Respiratory disorders - The effect of onions on all respiratory disorders is well known all over the world, even during the ancient times. The consumption of onions is highly recommended in cases of pneumonia, asthma, cough, sinusitis, and other respiratory disorders.
For more articles on health benefits of foods visit http://foodsanddiseases.com