Phloretin, also called trihydroxyphenol acetone, is a flavonoid that mainly exists in branches and leaves of apple or peel of apple, roots or bark of the apple tree, peel of litchi, Tibetan medicine "Eseye" and many other plants. Its chemical name is 246-trihydroxy-3-(4-hydroxyphenyl)propiophenone, the molecular formula is C15H14O5, molecular weight is 274.27, soluble in alkali solution, easily soluble in methanol, ethanol, and acetone, almost insoluble in water.
With the increasing market share of plant efficacy cosmetics, phloretin has attracted the attention of researchers in the beauty industry. And that's because of its multi-functional beauty efficacy. The studies found that phloretin not only has many pharmacological effects like antioxidant, anti-tumor, anti-inflammatory, immunosuppressive, and promoting bone formation, but also has the ability of whitening and acne removal. Phloretin can be absorbed by the human body directly. However, there is little phloretin existing in the plant. The phloretin exists in the form of its glycoside derivatives, phlorizin. The human body absorbs the gentiobioside in the gastric mucosa to remove the glycosidic group to produce gentiobioside before it enters the circulatory system and thus plays its role.
(1) Antioxidant and anti-free radical. Flavonoid compound has anti-lipid oxidation activity. It has been confirmed early in the 1960s that lots of polyhydroxy structures of flavonoids have significant antioxidant activity by chelating with the metal ion.
Phloretin has strong antioxidant activity, for which it has an antioxidant effect on oil and can remove free radicals from the skin.
According to the experiments, when the final system concentration reaches 13umolL, the inhibition rate of phloretin on lipid peroxidation is about 53%, and when the final system concentration is 32umolL, the DPPH radical scavenging rate of phloretin can be 74.6%. Free radical is harmful to health that is created by an oxidation reaction and is related to human degenerative diseases. Phloretin used externally can prevent carbohydrate components from entering epidermal cells, which can inhibit the excessive secretion of sebaceous glands and treat acne with strong secretion.
(2) Lighten spots and whiten skin. The results of researches showed that the whitening mechanism of phloretin is mainly to reduce the production of melanin by inhibiting the activity of tyrosinase. It is known that tyrosinase is an important catalytic enzyme for the synthesis of melanin, while phloretin has high inhibitory activity on tyrosinase, whose effect is better than arbutin and kojic acid. In addition, the inclusion complex of hydroxypropyl-β-Cyclodextrin and phloretin has a good inhibitory effect on tyrosinase activity. And other researches found that the combination of 34.9% ferulic acid, 35.1% phloretin, and 30% mixture of water-soluble VE has antioxidant and whitening effects.