EUR. J. Med. Chem.: Dendrobium extract can effectively whiten and protect skin

The stem of Dendrobium (Orchidaceae) is also called Dendrobium Dendrobium is a precious traditional Chinese medicine with a long history of application and high medicinal value Dendrobium can nourish yin, clear away heat, promote body fluid, nourish stomach and improve resistance, which is popular in recent years In fact, modern pharmacological studies show that Dendrobium has significant antioxidant activities in vivo and in vitro, and has anti-tumor, anti-aging and vasodilation effects Its active components have attracted attention at home and abroad The main chemical constituents of this genus are alkaloids, Phenanthrenes, benzenes, fluorenones, coumarins, sesquiterpenes, polysaccharides and volatile oils Siu Wai Tsang of the College of traditional Chinese medicine, Hong Kong Baptist University, Hong Kong, China, extracted a certain amount of stilbene compounds from two common Dendrobium species, of which trans resveratrol (1) and dihydroresveratrol (2) are typical antioxidants These stilbene compounds, especially dihydroresveratrol (2), reduce the production of melanin by inhibiting the activity of tyrosinase Then, using dihydroresveratrol (2) as the basic structural unit, the researchers synthesized 11 new dihydrostilbene derivatives (3-13), with high yield and purity Some of the new dihydrostilbene derivatives can not only resist the formation of melanin, but also are potential antioxidants They can scavenge oxygen free radicals in cells in a more effective way than water-soluble vitamin E, so as to protect the lipid on the cell membrane The oxidation of lipid is closely related to coronary heart disease, cancer, skin aging and so on New dihydrostilbene derivatives are potential antioxidants (source: European Journal of Medical Chemistry) The synthesis route of derivative 3-5 with dihydroresveratrol (2) as the basic structural unit is shown in the figure below K 2CO 3 (1.2mmol) was added to DMF (2ml) solution mixed with dihydroresveratrol (2,0.2mmol) and alkyl bromide (1.2mmol) The mixture was stirred to complete reaction at room temperature, diluted with H 2O (10ml) and washed with CH 2Cl 2 (10ml) for three times After the organic layer was combined, it was washed twice with NaCl aqueous solution, dried by anhydrous Na 2SO 4, concentrated in vacuum and purified by TLC The yield of compound 3-5 was 85-95% The synthesis route of derivative 3-5 (source: European Journal of Medical Chemistry) with dihydroresveratrol (2) as the basic structural unit to synthesize derivative 6-13 is shown in the figure below At 0 ℃, acyl chloride (1.2mmol) was added to dichloromethane (2ml) solution mixed with dihydroresveratrol (2,0.2mmol) and triethylamine (et3n, 1.2mmol) The mixture was heated to room temperature and stirred to complete reaction Dilute with H 2O (10ml) and wash the mixture with CH 2Cl 2 (10ml) three times After the organic layer was combined, it was washed twice with NaCl aqueous solution, dried by anhydrous Na 2SO 4, concentrated in vacuum and purified by TLC The compound 6-13 was obtained with a yield of 70-95% The synthesis of derivative 6-13 (source: European Journal of Medical Chemistry) with dihydroresveratrol (2) as the basic structural unit, generally speaking, the skin will become darker under sunlight, which is the main source of ultraviolet (UV) radiation in our daily life The oxidative stress induced by ultraviolet radiation constitutes the photoaging of skin and plays an important role in the external causes of skin aging Because oxidative stress can cause the breakdown of collagen and promote the production of inflammatory cytokines Melanin plays an important role in the prevention of UV and other physical factors UV can damage skin and other organs and tissues, such as photoaging, carcinogenesis, etc., while the absorption of UV by melanin can protect the body from its damage However, abnormal pigmentation of melanin deposition can affect the beauty of human skin, such as freckles and black spots Tyrosinase is the only known enzyme in melanin metabolism, which is synthesized by melanocytes Tyrosinase plays an important role in the production of melanin With the increase of tyrosinase activity, more melanin will be produced, and with the inhibition of tyrosinase activity, the ability of melanocytes to produce melanin will decrease accordingly It can be said that tyrosinase is the key to control the activity of melanocytes, which determines the rate of melanogenesis Therefore, the anti melanin ability of stilbene compounds, Dendrobium extract, depends on its inhibition of intracellular tyrosinase The researchers found that the extracts of Dendrobium, trans resveratrol (1) and dihydroresveratrol (2), can significantly inhibit the tyrosinase activity of human melanoma A375 cells and mouse melanoma B16 cells, thus reducing the content of melanin Among the derivatives (3-13) synthesized with dihydroresveratrol (2) as the basic structural unit, the inhibition of tyrosinase is more obvious, even more than vitamin C and butylated hydroxyanisole (BHA) can inhibit the formation of melanin The inhibitory effect of trans resveratrol (1) and dihydroresveratrol (2) and derivatives (3-13) on tyrosinase of melanoma A375 cells and mouse melanoma B16 cells (source: European Journal of Medical Chemistry) is very important for the recovery of skin pigmentation In order to explore the antioxidant free radical ability of Dendrobium extract, we used ABTS to evaluate stilbene compounds The standard curve of Trolox was drawn and the equivalent of free radical scavenging was calculated by ABTS experiment As shown in the figure below, trans resveratrol (1) and dihydroresveratrol (2) and derivatives (3-13) show the highest antioxidant capacity of Trolox equivalent Therefore, they are ideal ingredients for skin protectors and skin whitening agents Trans resveratrol (1) and dihydroresveratrol (2) and derivatives (3-13) showed the highest equivalent antioxidant capacity of Trolox (source: European Journal of Medical Chemistry) Based on the results of various biochemical tests, we conclude that trans resveratrol (1), dihydroresveratrol (2) and their derivatives (3-13) are potential nutrients for the treatment of skin pigmentation, because they reduce the formation of melanin in melanocytes by inhibiting the activity of tyrosinase In addition, they also showed strong antioxidant capacity This study is the first to report the anti melanin effect of dihydroresveratrol (2) and its derivatives (3-13) Therefore, Dendrobium will become a new material for whitening, freckle removing and anti-aging Paper link: http://