Glycosides from Muscari comosum. 1. Eucosterol glycoside and structure of its methanolysis products

1981 ◽  
Vol 59 (15) ◽  
pp. 2261-2265 ◽  
Author(s):  
Michelangelo Parrilli ◽  
Rosa Lanzetta ◽  
Vincenzo Dovinola ◽  
Matteo Adinolfi ◽  
Lorenzo Mangoni

A mixture of at least four glycosides has been isolated from bulbs of Muscari comosum. Acidic methanolysis of this mixture afforded a crystalline fraction consisting of four diols 1a differing in the configuration at the epimerizable C-20 and/or C-24 centers. Benzoylation of this diol fraction allowed the isolation of one pure dibenzoate, mp 175–176 °C, to which structure 1b was assigned on the basis of chemical and spectral evidence. This allowed the deduction that one of the aglycone moieties was 27-norlanostane triterpene eucosterol 4a. This conclusion has been confirmed by identification of 4a as the major product of the enzymatic hydrolysis of the glycoside mixture.


Author(s):  
Marcin Lukasiewicz ◽  
Anna Osowiec ◽  
Magdalena Marciniak


2018 ◽  
Author(s):  
Ángel Batallas ◽  
Erenio González ◽  
Carmen Salvador ◽  
Jonathan Villavicencio ◽  
Humberto González Gavilánez ◽  
...  


2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.



2020 ◽  
Vol 204 ◽  
pp. 106407 ◽  
Author(s):  
Shengxin An ◽  
Wenzhi Li ◽  
Fengyang Xue ◽  
Xu Li ◽  
Ying Xia ◽  
...  


2013 ◽  
Vol 85 (17) ◽  
pp. 8121-8126 ◽  
Author(s):  
Britta Opitz ◽  
Andreas Prediger ◽  
Christian Lüder ◽  
Marrit Eckstein ◽  
Lutz Hilterhaus ◽  
...  


2014 ◽  
Vol 98 (12) ◽  
pp. 5765-5774 ◽  
Author(s):  
Yaping Shang ◽  
Rongxin Su ◽  
Renliang Huang ◽  
Yang Yang ◽  
Wei Qi ◽  
...  




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