Kaempferol (3,4′,5,7-tetrahydroxyflavone) is a natural flavonol, a type of

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

, found in a variety of plants and plant-derived foods including

kale Kale (), or leaf cabbage, belongs to a group of cabbage (''Brassica oleracea'') cultivars grown for their edible leaves, although some are used as ornamentals. Kale plants have green or purple leaves, and the central leaves do not form a head ...

bean A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes th ...

s, tea,

spinach Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to central and western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either f ...

, and broccoli. Kaempferol is a yellow crystalline solid with a melting point of . It is slightly soluble in water and highly soluble in hot ethanol, ethers, and DMSO. Kaempferol is named for 17th-century German naturalist Engelbert Kaempfer.Kaempferol
at

Merriam-Webster Merriam-Webster, Inc. is an American company that publishes reference books and is especially known for its dictionaries. It is the oldest dictionary publisher in the United States. In 1831, George and Charles Merriam founded the company as ...

.com; retrieved October 20, 2017

Natural occurrence

Kaempferol is a secondary metabolite found in many plants, plant-derived foods, and traditional medicines. Its flavor is considered bitter.

In plants and food

Kaempferol is common in Pteridophyta, Pinophyta, and

Angiospermae Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

. Within Pteridophyta and Pinophyta, kaempferol has been found in diverse families. Kaempferol has also been identified in Dicotyledons and Monocotyledons of Angiosperms. The total average intake of flavonols and flavones in a normal diet is estimated as 23 mg/day, to which kaempferol contributes approximately 17%. Common foods that contain kaempferol include: apples, grapes, tomatoes, green tea, potatoes, onions, broccoli, Brussels sprouts, squash, cucumbers, lettuce, green beans, peaches, blackberries, raspberries, and spinach. Plants that are known to contain kaempferol include ''

Aloe vera ''Aloe vera'' () is a succulent plant species of the genus ''Aloe''. It is widely distributed, and is considered an invasive species in many world regions. An evergreen perennial, it originates from the Arabian Peninsula, but grows wild in tro ...

'', ''

Coccinia grandis ''Coccinia grandis'', the ivy gourd, also known as scarlet gourd, tindora and kowai fruit, is a tropical vine. It grows primarily in tropical climates and is commonly found in the Indian states, where it forms a part of the local cuisine. ''Coc ...

'', ''

Cuscuta chinensis ''Cuscuta chinensis'' Lam. is a stem holoparasite vine in the family Convolvulaceae. It was first described in China in 1786. Description ''C. chinensis'' is a thin, yellow vine lacking leaves or roots. It produces glomerulate to dense paniculif ...

'', ''

Euphorbia pekinensis ''Euphorbia pekinensis'', the Peking spurge, is a flowering plant native to Asia. Medicinal uses It is one of the 50 fundamental herbs used in traditional Chinese medicine, where it is called dàjǐ (). See also *Chinese herbology Chinese ...

'', '' Glycine max'', '' Hypericum perforatum'', '' Pinus sylvestris'', '' Moringa oleifera'', '' Rosmarinus officinalis'', '' Sambucus nigra'', and ''

Toona sinensis ''Toona sinensis'', commonly called Chinese mahogany, Chinese cedar, Chinese toon, beef and onion plant, or red toon (; hi, डारलू, d̩āralū; ms, suren; vi, hương xuân) is a species of ''Toona'' native to eastern and southeast ...

,'' and '' Ilex''. It also is present in

endive Endive () is a leaf vegetable belonging to the genus ''Cichorium'', which includes several similar bitter-leafed vegetables. Species include '' Cichorium endivia'' (also called endive), ''Cichorium pumilum'' (also called wild endive), and ''Cich ...

Biosynthesis

The biosynthesis of kaempferol occurs in four major steps: *

Phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amino a ...

is converted into

4-coumaroyl-CoA Coumaroyl-coenzyme A is the thioester of coenzyme-A and coumaric acid. Coumaroyl-coenzyme A is a central intermediate in the biosynthesis of myriad natural products found in plants. These products include Monolignol, lignols (precursors to lignin ...

*4-coumaroyl-CoA combines with three molecules of

malonyl-coA Malonyl-CoA is a coenzyme A derivative of malonic acid. Functions It plays a key role in chain elongation in fatty acid biosynthesis and polyketide biosynthesis. Fatty acid biosynthesis Malonyl-CoA provides 2-carbon units to fatty acids and commi ...

to form

naringenin chalcone Naringenin chalcone is a common chalconoid (or chalcone, not to be confused with the compound chalcone). It is synthesized from 4-coumaroyl-CoA and malonyl-CoA by chalcone synthase (CHS), a key enzyme in the phenylpropanoid pathway. Naringenin ...

(tetrahydroxychalcone) through the action of the enzyme chalcone synthase *Naringenin chalcone is converted to naringenin and then a hydroxyl group is added to form

dihydrokaempferol Aromadendrin (aromodendrin or dihydrokaempferol) is a flavanonol, a type of flavonoid. It can be found in the wood of ''Pinus sibirica''. Metabolism The enzyme dihydrokaempferol 4-reductase uses ''cis''-3,4-leucopelargonidin and NADP+ to pro ...

*Dihydrokaempferol has a double bond introduced into it to form kaempferol The amino acid phenylalanine is formed from the Shikimate pathway, which is the pathway that plants use in order to make aromatic amino acids. This pathway is located in the plant

plastid The plastid (Greek: πλαστός; plastós: formed, molded – plural plastids) is a membrane-bound organelle found in the Cell (biology), cells of plants, algae, and some other eukaryotic organisms. They are considered to be intracellular endosy ...

, and is the entry to the biosynthesis of phenylpropanoids. The phenylpropanoid pathway is the pathway that converts phenylalanine into tetrahydroxychalcone. Flavonols, including kaempferol, are products of this pathway.

Notes

External links

*
Flavonoid composition of tea: Comparison of black and green teas
{{Purinergics Antidepressants Xanthine oxidase inhibitors Flavonoid antioxidants Phytoestrogens Progestogens