Kaempferol

Formula

C₁₅H₁₀O₆

Molar mass

286.24 g·mol⁻¹

CAS

520-18-3

PubChem CID

5280863

Origin

A flavonol very widespread in the plant kingdom, present notably in capers, kale, spinach, broccoli, tea and many medicinal plants, most often as glycosides that digestive hydrolysis releases. It forms part of the ordinary daily dietary intake of polyphenols.

InChIKey

IYRMWMYZSQPJKC-UHFFFAOYSA-N

Editorial estimate, not clinical.

Kaempferol is a common dietary flavonol whose endocannabinoid interest rests on an indirect mechanism. It has no affinity for CB1 and CB2 receptors: it acts on fatty acid amide hydrolase, the enzyme that hydrolyses anandamide and therefore sets the lifetime of that endocannabinoid. Thors, Belghiti and Fowler screened twenty compounds against that target in 2008 and found it the most potent of the widely distributed natural flavonoids, with competitive-type inhibition and an inhibition constant of 5 micromolar. The same work showed that the effect holds on intact basophilic leukaemia cells, where the compound reduces anandamide uptake and its metabolism, and identified two flavonoids of more restricted distribution that are more active still, 7-hydroxyflavone and 3,7-dihydroxyflavone, with median inhibitory concentrations below the micromolar. That work follows on from the studies devoted to the isoflavones genistein and daidzein, active on the same enzyme in the same concentration range. The physiological reach of these results nevertheless calls for restraint: the effective concentrations lie in the micromolar range, far above the plasma concentrations attained after a flavonoid-rich meal, whose absorption and first-pass metabolism are moreover limiting. The compound is worth more as a chemical starting point for designing inhibitors than as an established dietary mechanism of action.

A flavonol arising from the phenylpropanoid route. Phenylalanine is converted into cinnamic acid then into coumaroyl-coenzyme A, which condenses with three units of malonyl-coenzyme A under the action of chalcone synthase. The chalcone obtained is cyclised into a flavanone, then hydroxylated and desaturated to give the flavonol. That route is proper to plants and bears no relation to the biosynthesis of the hemp cannabinoids.

Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.

Class

ECS modulator (research)

Origin

A flavonol very widespread in the plant kingdom, present notably in capers, kale, spinach, broccoli, tea and many medicinal plants, most often as glycosides that digestive hydrolysis releases. It forms part of the ordinary daily dietary intake of polyphenols.

Status

Unscheduled

1. 1.Thors et coll. 2008 : inhibition de la FAAH par le kaempférol et des flavonoïdes naturels apparentésPMID 18552875
2. 2.Thors et coll. 2007 : inhibition de la captation cellulaire de l'anandamide par la génistéine et la daidzéinePMID 17676056