Apigenin

Apigenin (chemically 4',5,7-trihydroxyflavone) is a flavone, one of the flavonoid classes of plant polyphenols. In plants it often occurs bound to sugars as glycosides such as apiin, from which the free aglycone apigenin is released. It is a yellow solid and is biosynthesized through the phenylpropanoid and flavone pathways by way of intermediates including naringenin.

The compound is widespread in the plant kingdom. Particularly rich sources include dried and fresh parsley, celery and celery seed, and chamomile, where apigenin makes up a large share of the flavonoids in the flowers. It is also present in foods and beverages such as oregano, thyme, and chamomile tea, so ordinary diets supply modest amounts.

Apigenin has been examined for a range of biological activities. One of the most studied is its interaction with the brain's GABA system: laboratory work identified apigenin from chamomile as a ligand that binds the benzodiazepine site of the GABA-A receptor and showed anxiety-reducing effects in animals at doses that did not cause strong sedation ^[1]. This finding is often cited to help explain the traditional use of chamomile as a calming tea. Apigenin has also been investigated for antioxidant and anti-inflammatory properties and, together with other polyphenols, for possible protective effects against neuroinflammation in models of Alzheimer's disease ^[2].

A practical limitation is that only a small fraction of dietary apigenin reaches the bloodstream. A controlled human study using apigenin-rich parsley found that plasma levels rose modestly and then fell within about a day, with only a small percentage of the ingested amount recovered, indicating limited oral bioavailability ^[3]. This has prompted interest in formulations intended to improve absorption.

Apigenin is a normal dietary constituent rather than a drug, and it is marketed as a dietary supplement, sometimes as a purified compound and sometimes within chamomile or other botanical extracts. It is generally regarded as having a good safety profile at dietary levels, though high-dose supplement use has not been extensively studied.

Generally well tolerated at supplement doses. It can add to the effects of other sedatives, so combining with alcohol, benzodiazepines, or other sleep aids should be done cautiously. It has estrogenic and enzyme-inhibiting activity in lab studies, so people with hormone-sensitive conditions or on medications metabolized by CYP enzymes should be thoughtful. Pregnancy safety isn't established.