Abstract
Highly efficient and regioselective synthesis of pharmacologically interesting aromatic esters of arbutin catalyzed by immobilized lipase from Penicillium expansum in co-solvent systems was successfully carried out. As compared to tetrahydrofuran solvent, the initial rate and substrate conversion of arbutin vanilylation were markedly enhanced in tetrahydrofuran-isopropyl ether (20%, v/v). Moreover, the effects of three reaction parameters (enzyme amount, temperature and substrate molar ratio of vinyl vanillic acid to arbutin) on 6′-O-vanilloyl-arbutin synthesis were scrutinized and the key process parameters were optimized using response surface methodology (RSM). The experimental data were fitted well to a second order polynomial model by using multiple regression analysis. The best combination of variables was 50°C, 93 U/mL and 11 for the reaction temperature, the enzyme amount and mole ratio of arbutin to vinyl vanilic acid, respectively, and which the reaction rate, substrate conversion and regioselectivity were as high as 8.2 mM/h, 93 and 99%. It was worth noting that a variety of aromatic esters of arbutin were obtained with much higher conversion (93–99%) at these optimal conditions.
Highlights
Arbutin as a soluble glycosylated phenol, is naturally derived from numerous plant species such as Arctostaphylos uva-ursi, Vaccinium vitis-idaea, Bergenia crassifolia, Arbutus unedo, and Heliciopsis lobata (Oliver et al, 2001; Pop et al, 2009; Qi et al, 2016; Jurica et al, 2017)
We first explored the effects of co-solvent mixtures on arbutin acylation with vinyl vanillate catalyzed by the immobilized lipase from Penicillium expansum (PEL)
One unit of lipase activity (U) corresponds to the enzyme amount required to synthesize 1 μmol arbutin butyrate per minute (The reaction was performed at 35◦C and 200 rpm in tetrahydrofuran containing 0.04 mmol arbutin, 0.2 mmol vinyl butyrate, and enzyme preparation)
Summary
Arbutin as a soluble glycosylated phenol (hydroquinone-β-D-Glucopyranoside), is naturally derived from numerous plant species such as Arctostaphylos uva-ursi, Vaccinium vitis-idaea, Bergenia crassifolia, Arbutus unedo, and Heliciopsis lobata (Oliver et al, 2001; Pop et al, 2009; Qi et al, 2016; Jurica et al, 2017). It is reported that arbutin ester derivatives displayed higher biological activity than the precursor compounds (Tokiwa et al, 2007; Chigorimbo-Murefu et al, 2009; Watanabe et al, 2009; Xu et al, 2014). Recent studies have shown that phenolic acids esters displayed potent biological activities than the precursors (Chigorimbo-Murefu et al, 2009; Ishimata et al, 2016). The ester derivatives of arbutin and aromatic acids are expected to possess stronger bioactivities. We first explored the effects of co-solvent mixtures on arbutin acylation with vinyl vanillate catalyzed by the immobilized lipase from Penicillium expansum (PEL).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
