Research

Onions - Research:
Oral administration of a butanol extract of Bulbus Allii Cepae (200mg) to subjects given a high-fat meal prior to testing suppressed platelet aggregation associated with a high-fat diet (62).
 
Administration of a butanol extract to patients with alimentary lipaemia prevented an increase in the total serum cholesterol, β-lipoprotein cholesterol, and β-lipoprotein and serum triglycerides (63, 64). A saponin fraction (50 mg) or the bulb (100 mg) also decreased serum cholesterol and plasma fibrinogen levels (65, 66). However, fresh onion extract (50 g) did not produce any significant effects on serum cholesterol, fibrinogen, or fibrinolytic activity in normal subjects (67, 68).
 
Antihyperglycaemic activity of Bulbus Allii Cepae has been demonstrated in clinical studies. Administration of an aqueous extract (100 mg) decreased glucose- induced hyperglycaemia in human adults (69). The juice of the drug (50 mg) administered orally to diabetic patients reduced blood glucose levels (22). Addition of raw onion to the diet of non-insulin-dependent diabetic subjects decreased the dose of antidiabetic medication required to control the disease (70). However, an aqueous extract of Bulbus Allii Cepae (200mg) was not active (71).
 
The immediate and late cutaneous reactions induced by injection of rabbit anti-human IgE-antibodies into the volar side of the forearms of 12 healthy volunteers were reduced after pretreatment of the skin with a 50% ethanol onion extract (1). Immediate and late bronchial obstruction owing to allergen inhalation was markedly reduced after oral administration of a 5% ethanol onion extract 1 hour before exposure to the allergen (1).
 
In one clinical trial in 12 adult subjects, topical application of a 45% ethanolic onion extract inhibited the allergic skin reactions induced by anti-IgE (72).

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