Preparatory production of quercetin-3-β-d-glucopyranoside using alkali-tolerant thermostable α-l-rhamnosidase from Aspergillus terreus

α‐L‐Rhamnosyl‐β‐D‐glucosidase (Rutinosidase) from Aspergillus niger: Characterization and Synthetic Potential of a Novel Diglycosidase

“…[25] We have exemplified this selective enzymatic trimming of rutinosides in the preparation of quercetin 3-b-glucopyranoside from rutin. [26] We have thus provided an affordable tool for the preparation of rutinosides of various aglycones at a preparative scale, which will enable further detailed study of these compounds.…”

“…[26] Substrate 6 (150 mg, 0.498 mmol) and rhamnose (7, 410 mg, 2.498 mmol) were dissolved in citrate-phosphate buffer (4.0 mL, 50 mM, pH 5.0), a-l-rhamnosidase (7 U) was added and the mixture was incubated at 35 8C (Thermomixer, Eppendorf, DE). The reaction was monitored by TLC (n-propanol/H 2 O/NH 4 OH = 7:2:1, v/v/v; Kieselgel 60 F 254 , Merck, DE) and stopped by heating (100 8C, 10 min), typically after 72 h. Spots on TLC were visualized by charring with 5% H 2 SO 4 in EtOH.…”

Sulfation modulates the cell uptake, antiradical activity and biological effects of flavonoids in vitro: An examination of quercetin, isoquercitrin and taxifolin

“…Isoquercitrin (quercetin 3-O-b-D-glucopyranoside, 150 mg, 0.323 mmol; prepared as described previously 38 ) was sulfated using the same procedure as for quercetin. Isoquercitrin 4 0 -O-sulfate (2) was obtained as a yellowish solid (120 mg).…”

“…38 Taxifolin (96% purity) was obtained from Amagro (Prague, Czech Republic). Quercetin (98% purity), dimethyl sulfoxide (DMSO) and solvents for HPLC were purchased from Sigma-Aldrich.…”

The possible presence of natural β-d-glucosidase inhibitors in jujube leaf extract

“…Isoquercitrin can be produced by selectively hydrolyzing rhamnose from rutin, and a number of methods have been developed to de-rhamnosylate rutin. Methods for the production of isoquercitrin using this approach include acid hydrolysis, heating, biological transformation (Wang, Sun, Yu, Wu, & Guo, 2013;Weignerová, Marhol, Gerstorferová, & Křen, 2012), and enzymatic transformation, the last of which has become the favored method due to its economic merits and applicability to the food industry.…”