Synthesis, oxygen radical absorbance capacity, and tyrosinase inhibitory activity of glycosides of resveratrol, pterostilbene, and pinostilbene

Abstract

The stilbene compound resveratrol was glycosylated to give its 4'-O-β-D-glucoside as the major product in addition to its 3-O-β-D-glucoside by a plant glucosyltransferase from Phytolacca americana expressed in recombinant Escherichia coli. This enzyme transformed pterostilbene to its 4'-O-β-D-glucoside, and converted pinostilbene to its 4'-O-β-D-glucoside as a major product and its 3-O-β-D-glucoside as a minor product. An analysis of antioxidant capacity showed that the above stilbene glycosides had lower oxygen radical absorbance capacity (ORAC) values than those of the corresponding stilbene aglycones. The 3-O-β-D-glucoside of resveratrol showed the highest ORAC value among the stilbene glycosides tested, and pinostilbene had the highest value among the stilbene compounds. The tyrosinase inhibitory activities of the stilbene aglycones were improved by glycosylation; the stilbene glycosides had higher activities than the stilbene aglycones. Resveratrol 3-O-β-D-glucoside had the highest tyrosinase inhibitory activity among the stilbene compounds tested.

Natural and Bioinspired Phenolic Compounds as Tyrosinase Inhibitors for the Treatment of Skin Hyperpigmentation: Recent Advances

“…Several derivatives of the parent resveratrol have been described as potential depigmenting agents, with oxyresveratrol (IC50 = 1.7 μM) [55] and particularly dihydrooxyresveratrol (IC50 = 0.3 μM) [55] among the most active compounds. Recently, glycosylation has been reported to improve the tyrosinase inhibitory activities of both resveratrol and its methylated analogues pterostilbene and pinostilbene [60]. Another major class of mushroom tyrosinase inhibitors is represented by hydroxystilbenes ( Figure 5).…”

“…Several derivatives of the parent resveratrol have been described as potential depigmenting agents, with oxyresveratrol (IC 50 = 1.7 µM) [55] and particularly dihydrooxyresveratrol (IC 50 = 0.3 µM) [55] among the most active compounds. Recently, glycosylation has been reported to improve the tyrosinase inhibitory activities of both resveratrol and its methylated analogues pterostilbene and pinostilbene [60]. Moving to simple phenols, significant inhibition activity has been described for 4-hydroxybenzyl alcohol (IC50 = 6 μM) [61] and isoeugenol (IC50 = 33.3 μM) [62], which would appear more efficient than resorcinol [55] or rhododendrol [63] themselves.…”

Resveratrol derivatives from Commiphora africana (A. Rich.) Endl. display cytotoxicity and selectivity against several human cancer cell lines

“…Another study revealed that pinostilbene displayed in vitro cytotoxicity with IC 50 value of 78.13 μM against NCI‐H187 cell line (Lertnitikul et al, ). Pinostilbene was shown to possess high antioxidant capacity displaying a value of 5.01 Trolox equivalents/μM in an oxygen radical absorbance capacity assay (Uesugi et al, ). The antioxidant capacity could have been contributed to the cytotoxicity of pinostilbene, reported in the present study.…”

Phytolacca americana PaGT2 is an ambidextrous polyphenol glucosyltransferase

“…Three glycosyltransferases namely Pa GT1, Pa GT2, and Pa GT3 have been isolated from the callus tissues of P. americana (11). Among the three Pa GTs, Pa GT3 can glycosylate a wide variety of substrates, such as capsaicin, flavonoids, hydroxyflavones, and stilbenoids (11, 22, 23). Although Pa GT2 can also regioselectively glucosylate stilbenoids and flavonoids, the detail has not been much explored.…”