Onions are high in flavonoids, and flavonoids include quercetin. Therefore, quercetin is high content in onions.
Quercetin Introduction
The chemical formula of quercetin is C15H10O7, which is a plant secondary metabolite that widely exists in nature. It is present in many vegetables and fruits. It is also found in foods such as tea, red wine, olive oil and propolis. There is a double bond between the 2 and 3 positions in its molecular formula, and there are 2 hydroxyl groups. It has the function of accepting free radicals generated in the oxidation process of metal chelating agents or oils, that is, it has the functions of anti-oxidation and scavenging free radicals. In addition, it also has physiological activities such as anticancer, anti-inflammatory and antibacterial.
Onion Contain High Quercetin
The content of quercetin in more than 200 kinds of foods, including cereals, beans, vegetables and fruits, was detected by high performance liquid chromatography. The results showed that fennel, onion, and pea tips had the highest content of cyptin in vegetables. Onion is a biennial herb in the Alliaceae genus (Allium) with fleshy scales and scale buds forming the product organ. Quercetin is mainly found in onion bulbs and a small part in onion leaves.
The content of onion quercetin varies in different parts and in different states. In fresh weight state, the content of onion is 26.62mg/kg. The content in the dry weight state is much higher than that in the fresh weight state.
Summary
As an important active substance in onion, quercetin has a wide range of physiological activities. For example, it has antioxidant effects, free radical scavenging effects, anti-cancer effects, and therapeutic effects on cardiovascular and endocrine systems.