Biotransformation of mulberroside A from Morus alba results in enhancement of tyrosinase inhibition

Abstract

Mulberroside A, a glycosylated stilbene, was isolated and identified from the ethanol extract of the roots of Morus alba. Oxyresveratrol, the aglycone of mulberroside A, was produced by enzymatic hydrolysis of mulberroside A using the commercial enzyme Pectinex. Mulberroside A and oxyresveratrol showed inhibitory activity against mushroom tyrosinase with an IC(50) of 53.6 and 0.49 microM, respectively. The tyrosinase inhibitory activity of oxyresveratrol was thus approximately 110-fold higher than that of mulberroside A. Inhibition kinetics showed mulberroside A to be a competitive inhibitor of mushroom tyrosinase with L-tyrosine and L-DOPA as substrate. Oxyresveratrol showed mixed inhibition and noncompetitive inhibition against L-tyrosine and L-DOPA, respectively, as substrate. The results indicate that the tyrosinase inhibitory activity of mulberroside A was greatly enhanced by the bioconversion process.

Evaluation of the inhibition of mushroom tyrosinase and cellular tyrosinase activities of oxyresveratrol: comparison with mulberroside A

“…Oxyresveratrol and mulberroside A have displayed antioxidant, anti-inflammatory, and anti-browning activities, those of oxyresveratrol being much greater than mulberroside A 10,25 . We previously reported that oxyresveratrol inhibits mushroom tyrosinase via a mixed inhibition with l-tyrosine as a substrate, resulting in approximately 110-fold more inhibition than mulberroside A 17 . Following oral administration, mulberroside A is metabolized in the liver or digestive tract, resulting in an almost complete conversion to oxyresveratrol, which is easily transported in tissue 9 .…”

“…Oxyresveratrol also did not show stronger inhibitory activity than mulberroside A on melanin synthesis in S. bikiniensis. The 50% inhibition concentration (IC 50 ) values of mulberroside A and oxyresveratrol were 53.6 µM and 0.49 µM, respectively, with L-tyrosine as the substrate 17 . The relative in vitro activities of mushroom tyrosinase using L-DOPA as a substrate were 73.9% and almost 100% with treatment of 5 µM oxyresveratrol or 5 µM mulberroside A, respectively (Figure 1).…”

“…Although some of them were investigated on the inhibition of cellular tyrosinase, the tyrosinase inhibitory activity of the compounds was mainly evaluated via the inhibition rate of mushroom tyrosinase activity. Mulberroside A was enzymatically transformed into oxyresveratrol using Pectinex® and reported that oxyresveratrol showed more mushroom tyrosinase inhibitory activity than mulberroside A 17 . In the present study, the inhibition effects of oxyresveratrol on mushroom dihydroxyphenylalanine (DOPA) oxidase activity, cellular DOPA oxidase activity and melanin biosynthesis in melanoma cells were evaluated and were compared to those of mulberroside A.…”

Enhancement of the Tyrosinase Inhibitory Activity of Mori Cortex Radicis Extract by Biotransformation UsingLeuconostoc paramesenteroidesPR

“…23,24,[30][31][32][33][34] Because the deglucosylated form of hydroxystilbene has more potent tyrosinase inhibitory activity than its glucosylated form, 22,35) the biotransformation of stilbene glycoside to an aglycone has been performed using commercial deglycosylation enzyme products such as cellulase and Pectinex Ò . 22,36) Although these products are used widely as hydrolyzing enzymes, we reasoned that a biotransformation process based on microbial fermentation without a purification process of enzyme sources might represent a more convenient and economical method for the industrial production of bioactive herbal extracts. Therefore, suitable microbial strains were investigated to identify the most efficient organism for the biotransformation of the MA in MCR extract to OXY.…”

“…19) Moreover, OXY showed approximately 110-fold higher tyrosinase inhibitory activity than did MA against L-tyrosine substrate. 22) Flavonoids generally exist in glycosylated form in plant and food sources, and upon ingestion are absorbed after conversion into deglycosylated aglycones by intestinal enzymes and/or gut microbial enzymes. Flavonoid aglycones exhibit improved bioavailability and greater bioactivity than the respective glycosidic forms.…”