The results suggest that the a diet rich in such flavonoids could protect and/or reduce the occurrence of asthma and other allergies associated with the immunoglobulin E (IgE).
"The intake of apigenin may alleviate symptoms and even prevent allergic diseases," wrote lead author Satomi Yano in the Journal of Agricultural and Food Chemistry (Vol. 54, pp. 5203-5207).
However, since apigenin-rich foods, such as celery and parsley are often associated with adverse food reactions, it may be that the benefits of the flavonoid could perhaps be better obtained from supplements.
According to the American Lung Association, almost 20m Americans suffer from asthma. The condition is reported to be responsible for over 14m lost school days in children, while the annual economic cost of asthma is said to be over $16.1bn.
According to the European Federation of Allergy and Airway Diseases Patients Association (EFA), over 30m Europeans suffer from asthma, costing Europe €17.7bn every year. The cost due to lost productivity is estimated to be around €9.8bn.
The researchers from Kyushu University supplemented the diets of mice with apigenin for two weeks, and measured the levels of certain immune and inflammatory markers, such as IgE, IgG, IgM, IgA, and cytokine expression.
After two weeks of supplementation, lead author Satomi Yano reported that only IgE levels had been suppressed significantly (50 per cent), compared to a control group of mice not receiving the flavonoid supplement.
"IgE is one of the major mediators of the immediate hypersensitivity reaction that underlies atopic conditions such as seasonal allergy, food allergy, asthma, and anaphylaxis," explained the researchers.
The researchers also found that production of Regulated upon Activation Normal T cell Expressed and Secreted (RANTES), a cytokine associated with inflammation, and soluble tumor necrosis factor receptor I (sTNFRI) were also down-regulated by the apigenin diet.
"These results suggest that a diet containing apigenin can reduce serum IgE and inflammatory cytokines such as RANTES and sTNFRI in mice," wrote the researchers.
Apigenin is found in a variety of foods including apples, beans, broccoli, celery, cherries, grapes, leeks, onions, parsley and tomatoes, as well as plant-derived beverages like tea and wine.
However, the researchers stressed that "a vegetable very rich in apigenin such as parsley and celery is also very often involved in adverse reactions to food.
"Thus, the results coming from this study need to be deeply investigated in the future."
Previous research into flavonoids, and particularly apignenin, has focused on the potential anti-cancer properties of the compounds.
A report last October by researchers from Case Western Reserve University in the Federation of American Societies for Experimental Biology journal (doi:10.1096/fj.05-3740fje), reported that apigenin slowed prostate tumour growth in mice orally fed doses of 20mcg and 50mcg daily two weeks before implanting a prostate tumour and then continued to feed the compound for eight weeks.