Phlorizin is a

glucoside A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. The name was o ...

phloretin Phloretin is a dihydrochalcone, a type of natural phenol. It can be found in apple tree leaves and the Manchurian apricot. Metabolism In rats, ingested phlorizin is converted into phloretin by hydrolytic enzymes in the small intestine. Ph ...

, a

dihydrochalcone Dihydrochalcone (DHC) is the organic compound with the formula C6H5C(O)(CH2)2C6H5. It is the reduced derivative of chalcone (C6H5C(O)(CH)2C6H5). It is white solid that is soluble in many organic solvents. Dihydrochalcone per se is often minor si ...

. A white solid, samples often appear yellow owing to impurities. It is of sweet taste and contains four molecules of water in the crystal. Above 200 °C, it decomposes to give rufin. It is poorly soluble in

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...

and cold water, but soluble in

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

and hot water. Upon prolonged exposure to aqueous solutions phlorizin

hydrolyzes Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

to phloretin and glucose.

Occurrence

Phlorizin is found primarily in unripe ''Malus'' (

apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

) root bark of

, and trace amounts have been found in strawberry. In ''Malus'', it is most abundant in vegetative tissues (such as leaves and bark) and seeds. Closely related species, such as

pear Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the p ...

(''Pyrus communis''),

cherry A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit). Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The nam ...

, and other

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

trees in the ''

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are ''Alchemilla'' (270), ''Sorbus ...

'' do not contain phloridzin. Phloridzin is a phytochemical that belongs to the class of

polyphenol Polyphenols () are a large family of naturally occurring organic compounds characterized by multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of ...

s. In natural sources, it may occur with other polyphenols such as

quercetin Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor a ...

catechin Catechin is a flavan-3-ol, a type of secondary metabolite providing antioxidant roles in plants. It belongs to the subgroup of polyphenols called flavonoids. The name of the catechin chemical family derives from ''catechu'', which is the tannic ...

epicatechin Catechin is a flavan-3-ol, a type of secondary metabolite providing antioxidant roles in plants. It belongs to the subgroup of polyphenols called flavonoids. The name of the catechin chemical family derives from ''catechu'', which is the tannic ...

procyanidin Procyanidins are members of the proanthocyanidin (or condensed tannins) class of flavonoids. They are oligomeric compounds, formed from catechin and epicatechin molecules. They yield cyanidin when depolymerized under oxidative conditions. See the ...

s, and

rutin Rutin, also called rutoside, quercetin-3-O-rutinoside and sophorin, is the glycoside combining the flavonol quercetin and the disaccharide rutinose (α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranose). It is a flavonoid found in a wide variety of pla ...

Pharmacology

Phlorizin is an inhibitor of

SGLT1 Sodium/glucose cotransporter 1 (SGLT1) also known as solute carrier family 5 member 1 is a protein in humans that is encoded by the gene which encodes the production of the SGLT1 protein to line the absorptive cells in the small intestine and th ...

and

SGLT2 The sodium/glucose cotransporter 2 (SGLT2) is a protein that in humans is encoded by the (solute carrier family 5 (sodium/glucose cotransporter)) gene. Function SGLT2 is a member of the sodium glucose cotransporter family, which are sodium-d ...

because it competes with D-glucose for binding to the carrier; this action reduces

renal The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...

glucose transport, lowering the amount of glucose in the blood. Phlorizin was studied as a potential pharmaceutical treatment for

type 2 diabetes Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, ...

, but has since been superseded by more selective and more promising synthetic analogs, such as

empagliflozin Empagliflozin, sold under the brand name Jardiance among others, is an antidiabetic medication used to improve glucose control in people with type2 diabetes, to reduce the risk of cardiovascular death in adults with type2 diabetes and establis ...

canagliflozin Canagliflozin, sold under the brand name Invokana among others, is a medication used to treat type 2 diabetes. It is a third-line medication to be tried after metformin, a first-line medication for type 2 diabetes. It is used together with ex ...

and

dapagliflozin Dapagliflozin, sold under the brand names Farxiga (US) and Forxiga (EU) among others, is a medication used to treat type 2 diabetes. It is also used to treat adults with heart failure and chronic kidney disease. Common side effects include hy ...

. Phlorizin is not an effective drug because when orally consumed, it is nearly entirely converted into phloretin by hydrolytic enzymes in the small intestine.

References

{{Sodium-glucose transporter modulators Dihydrochalcones Phenol glucosides