Phlorizin is a
glucoside of
phloretin, a
dihydrochalcone. A white solid, samples often appear yellowing 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 and cold water, but soluble in
ethanol and hot water. Upon prolonged exposure to aqueous solutions phlorizin
hydrolyzes to phloretin and glucose.
[1]
Occurrence
Phlorizin is found primarily in unripe Malus (
apple)[2] root bark of
apple,[3] and trace amounts have been found in strawberry.[4] In Malus, it is most abundant in vegetative tissues (such as leaves and bark) and seeds. Closely related species, such as
pear (Pyrus communis),
cherry, and other
fruit trees in the Rosaceae do not contain phlorizin.[5] Phlorizin is a phytochemical that belongs to the class of
polyphenols. In natural sources, it may occur with other polyphenols such as
quercetin,
catechin,
epicatechin,
procyanidins, and
rutin.
Pharmacology
Phlorizin is an inhibitor of
SGLT1 and
SGLT2 because it competes with
D-glucose for binding to the carrier; this action reduces
renalglucose transport, lowering the amount of glucose in the blood.[6][7] Phlorizin was studied as a potential pharmaceutical treatment for
type 2 diabetes, but has since been superseded by more selective and more promising synthetic
analogs, such as
empagliflozin,
canagliflozin and
dapagliflozin.[8] Phlorizin is not an effective drug because when orally consumed, it is nearly entirely converted into phloretin by hydrolytic enzymes in the small intestine.[9][10]
References
^Ehrenkranz, Joel R. L.; Lewis, Norman G.; Ronald Kahn, C.; Roth, Jesse (2005). "Phlorizin: A review". Diabetes/Metabolism Research and Reviews. 21 (1): 31–38.
doi:
10.1002/dmrr.532.
PMID15624123.
S2CID37909306.
^Makarova, Elina; Górnaś, Paweł; Konrade, Ilze; Tirzite, Dace; Cirule, Helena; Gulbe, Anita; Pugajeva, Iveta; et al. (2015). "Acute anti-hyperglycaemic effects of an unripe apple preparation containing phlorizin in healthy volunteers: A preliminary study". Journal of the Science of Food and Agriculture. 95 (3): 560–568.
doi:
10.1002/jsfa.6779.
PMID24917557.
^Chao, Edward C.; Henry, Robert R. (2010). "SGLT2 inhibition – A novel strategy for diabetes treatment". Nature Reviews Drug Discovery. 9 (7): 551–559.
doi:
10.1038/nrd3180.
PMID20508640.
^Idris, Iskandar; Donnelly, Richard (2009). "Sodium–glucose co-transporter-2 inhibitors: An emerging new class of oral antidiabetic drug". Diabetes, Obesity and Metabolism. 11 (2): 79–88.
doi:
10.1111/j.1463-1326.2008.00982.x.
PMID19125776.