Onion: Onion is a bulbous perennial or biennial herb believed to be native to western Asia. Numerous varieties are cultivated worldwide. Onion bulb has been used as a food for thousands of years. It has also been used medicinally. Its actions were considered to be comparable to those of garlic, though milder.
Onion is used for loss of appetite and prevention of atherosclerosis and age related change in blood vessels. May reduce the risk of gastric cancer.
The Commission E reported antibacterial, lipid, and blood pressure-lowering properties and inhibition of thrombocyte aggregation. Recent investigations suggest that therapies aimed toward the prevention of atherosclerosis should include a diet rich with onions. Contemporary studies have shown that onions, like garlic, may inhibit platelet aggregation and interfere with fibrinolyis. Clinical studies have reported that onions lowered lipid levels and inhibited the formation of blood clots. Onions are also cooked in milk and eaten in order to clear congestion in the lungs.
Onion bulb contains numerous organic sulfur compounds, including trans-S-(1-propenyl) cysteine sulfoxide, S-methyl-cysteine sulfoxide, S-propylcysteine sulfoxide, and cycloalliin; flavonoids; phenolic acids; sterols including cholesterol, stigmasterol, b-sitosterol; saponins; sugars; and a trace of volatile oil composed mainly of sulfur compounds, including dipropyl disulfide. A fresh onion bulb contains fructans with a low degree of polymerization, flavonoids, and sulfur-containing compounds. When an onion bulb is bruised, the sulfoxides are degraded by alliinase and release pyruvic acid and alkylthiosulfinates, which rapidly form into disulfides.
Unless otherwise prescribed: 50 g per day of fresh bulb or 20 g per day of cut dried bulb, pressed juice from fresh onions and other oral galenical preparations. Dried bulb: 20 g. Fresh bulb: 50 g. Infusion: Steep 1–2 teaspoons in 120 ml water. Tincture: 5 ml (1 teaspoon), three to four times daily. If onion preparations are used over several months, the daily maximum amount for diphenylamine is 0.035 g.