apigenin

Apigenin comes from the same single botanical as bisabolol, chamomile. In the living flower it sits mostly bound to a sugar, as apigenin-7-glucoside, and drying costs it: fresh flowers measured about 3 milligrams of the glucoside per gram, gentle drying kept about 2, and an 80-degree oven cut it to 1, a two-thirds loss under the harshest regime tested. Brewing changes the mixture again. A 2010 analysis comparing chamomile flowers with the tea made from them found the tea richer in flavonoid glycosides like rutin and poorer in free apigenin and its glucoside, so a cup is a different chemical mixture from the flower, not a dilution of it.

Apigenin, C₁₅H₁₀O₅, is a flavone, and the specific claim made about it comes from a 1995 paper by Viola and colleagues, who found it displaced a labeled benzodiazepine from brain receptors with a binding constant of 4 micromolar, then showed mice given apigenin behaved less anxiously in a plus-maze, without sedation or muscle relaxation. It is a real result from a careful paper, but 4 micromolar is a modest affinity for a drug, and it comes from a test tube assay plus a mouse behavior test, not a measurement in a person.

A year after that paper, another group fractionated chamomile heads looking for the same benzodiazepine-displacing activity and found the main agent responsible was GABA itself, which the flower simply contains: nobody has since shown that a cup of tea delivers enough free apigenin to the brain to matter at all. Chamomile's clinical trials back the caution up. The best of them used 220 to 1,500 milligrams a day of a standardized capsule extract, not an infusion, and a dedicated insomnia trial found no significant difference from placebo at a dose the authors calculated as the equivalent of 15 grams of chamomile flowers a day, more than could feasibly be brewed as tea. Europe's own herbal monograph lists chamomile flower for minor gastrointestinal complaints and skin washes; sleep and anxiety are not on that list. In this library apigenin's job is flavor and a scent of calm, in five recipes, always traced to the same flower.