121-79-9Relevant articles and documents
Characterization of Aspergillus fumigatus CAS-21 tannase with potential for propyl gallate synthesis and treatment of tannery effluent from leather industry
Cavalcanti, Rayza Morganna Farias,Jorge, Jo?o Atílio,Guimar?es, Luis Henrique Souza
, (2018)
One of the tannase isoforms produced by the fungus Aspergillus fumigatus CAS-21 under submerged fermentation (SbmF) was purified 4.9-fold with a 10.2% recovery. The glycoprotein (39.1% carbohydrate content) showed an estimated molecular mass of 60?kDa. Optimum temperature and pH for its activity were 30–40?°C and 5.0, respectively. It showed a half-life (t50) of 60?min at 45 and 50?°C, and it was stable at pH 5.0 and 6.0 for 3?h. The tannase activity was insensitive to most salts used, but it reduced in the presence of Fe2(SO4)3 and FeCl3. On contrary, in presence of SDS, Triton-X100, and urea the enzyme activity increased. The Km value indicated high affinity for propyl gallate (3.61?mmol L?1) when compared with tannic acid (6.38?mmol L?1) and methyl gallate (6.28?mmol L?1), but the best Kcat (362.24?s?1) and Kcat/Km (56.78?s?1 mmol?1 L) were obtained for tannic acid. The purified tannase reduced 89 and 25% of tannin content of the leather tannery effluent generated by manual and mechanical processing, respectively, after 2-h treatment. The total phenolic content was also reduced. Additionally, the enzyme produced propyl gallate, indicating its ability to do the transesterification reaction. Thus, A. fumigatus CAS-21 tannase presents interesting properties, especially the ability to degrade tannery effluent, highlighting its potential in biotechnological applications.
Enhancement of transesterification-catalyzing capability of bio-imprinted tannase in organic solvents by cryogenic protection and immobilization
Nie, Guangjun,Chen, Zhen,Zheng, Zhiming,Jin, Wei,Gong, Guohong,Wang, Li,Yue, Wenjin
, p. 1 - 6 (2013)
Improvement of transesterification-catalyzing capability of bio-imprinted tannase is a crucial question of whether to be efficiently utilized in organic media. As for biotransformation of tannic acid to propyl gallate, bio-imprinting technique can dramatically enhance the transesterification-catalyzing capability of tannase. In this work, both cryogenic protection and immobilization were utilized to further improve its apparent catalytic capability in organic media. The results show that Triton-X-100, mannose, and magnesium ion all have a positive effect on cryogenic protection of the tannase. Particularly, combinational application of the three cryoprotectants increases its catalytic performance by 2.7-fold factor. Also, immobilization further elevates its catalytic capability by 2.1 folds. Noteworthily, the coupling application of immobilization and cryo-protection can cause the conversion rate of substrate of the bio-imprinted tannase to increase to a promising 70%. Consequently, it will be helpful to fully utilize tannase in organic phase.
Self-assembled tetramethyl cucurbit[6]uril-polyoxometalate nanocubes as efficient and recyclable catalysts for the preparation of propyl gallate
Li, Shuang,Xia, Wen,Zhang, Yunqian,Tao, Zhu
, p. 11895 - 11900 (2020)
The development of cucurbit[n]urils-polyoxometalate (Q[n]-POM) hybrids with the same microshape and nanoscale features is highly desirable, yet remains a great challenge. Herein, we design and synthesize a class of Q[n]-POM hybrids and tetramethyl cucurbit[6]uril-phosphomolybdic acid (TMeQ[6]-PMA) nanocubes (NCs) via a facile one-step self-assembly method, as heterogeneous acid catalysts for greatly boosting the catalysts in term of activity and stability for the esterification of gallic acid and n-propanol to propyl gallate (PG). The Fourier transform infrared (FTIR) spectroscopy reveals that the self-assembled mechanism of TMeQ[6]-PMA NCs based on the outer-surface interaction of Q[n]s. The temperature programmed desorption experiments with ammonia and FTIR analysis of the pre-adsorbed pyridine results confirm that the coexistence of medium and strong acid sites and a larger number of Lewis acid sites other than Br?nsted acidic sites on the catalyst surface. These new features make the as-prepared TMeQ[6]-PMA NCs exhibit a high PG conversion (95.6percent) and excellent stability, which epresents a better catalytic performance than other reported catalysts.
Synthesis of propyl gallate from tannic acid catalyzed by tannase from Aspergillus oryzae: Process optimization of transesterification in anhydrous media
Nie, Guangjun,Liu, Hui,Chen, Zhen,Wang, Peng,Zhao, Genhai,Zheng, Zhiming
, p. 102 - 108 (2012)
Improving the catalytic capability of enzyme is an important challenge of biocatalysis in organic medium. Optimization of organic reaction system and reaction mode can elevate the catalytic ability. In order to enhance the catalytic efficiency of tannase-catalyzed transesterification from tannic acid, process parameters of the reaction and reaction mode were optimized further to improve the conversion rate of substrate. The result showed that with hexane as solvent, a conversion rate of substrate, 75%, was achieved at 40 °C in 20 mL reaction mixture composed of 0.75% water and 7.5% n-propanol, and that semicontinuous catalysis was the most favorable for production of propyl gallate, its average production rate was 2.5-fold that of batch catalysis. By SCC, a noted computative conversion rate of approximate, 90%, was obtained. Thus, it is expected that this study may present an efficient and ecofriendly method for industrial production of PG.
Potentiation of vasoconstrictor response and inhibition of endothelium-dependent vasorelaxation by gallic acid in rat aorta
Sanae, Fujiko,Miyaichi, Yukinori,Hayashi, Hisao
, p. 690 - 693 (2002)
In the isolated rat thoracic aorta, gallic acid potentiated the vasoconstrictor response to phenylephrine. The potentiation produced by gallic acid was absent in endothelium-denuded arteries. The potentiation was abolished by NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis, and slightly attenuated by an addition of L-arginine, while indomethacin or BQ610 had no effect. The potentiation of response to phenylephrine was not found for structural modifications of gallic acid, except for caffeic acid. Gallic acid also inhibited vasorelaxation induced by acetylcholine, sodium nitroprusside or prostacyclin, especially that by acetylcholine. The effect on vasorelaxation induced by acetylcholine was decreased by esterification of the carboxy group of gallic acid, and in the absence or by the methylation of the o-dihydroxy group. Caffeic acid inhibited the vasorelaxation, though the effect was smaller than that of gallic acid. These findings indicate that gallic acid produces a potentiation of contractile response and inhibition of vasorelaxant responses, probably through inactivation of nitric oxide (NO), in which endothelially produced NO is principally involved, and that the modification of functional groups of the gallic acid molecule abolishes the potentiation of contractile response and attenuates the inhibition of vasorelaxant responses.
Synthesis of propyl gallate by transesterification of tannic acid in aqueous media catalysed by immobilised derivatives of tannase from Lactobacillus plantarum
Fernandez-Lorente, Gloria,Bolivar, Juan Manuel,Rocha-Martin, Javier,Curiel, Jose A.,Mu?oz, Rosario,De Las Rivas, Blanca,Carrascosa, Alfonso V.,Guisan, Jose M.
, p. 214 - 217 (2011)
Immobilised derivatives of tannase from Lactobacillus plantarum were able to catalyse the transesterification of tannic acid by using moderate concentrations of 1-propanol in aqueous media. Transesterification of tannic acid was very similar to transesterification of methyl gallate. The synthetic yield depended on the pH and concentration of 1-propanol, although it did not vary much when using 30% or 50% 1-propanol. Synthetic yields of 45% were obtained with 30% of 1-propanol at pH 5.0. The product was chromatographically pure, and the reaction by-product was 55% pure gallic acid. On the other hand, immobilised tannase was fairly stable under optimal reaction conditions.
Polyhydroxybenzoic acid derivatives as potential new antimalarial agents
Degotte, Gilles,Francotte, Pierre,Pirotte, Bernard,Frédérich, Michel
, (2021/08/07)
With more than 200 million cases and 400,000 related deaths, malaria remains one of the deadliest infectious diseases of 2021. Unfortunately, despite the availability of efficient treatments, we have observed an increase in people infected with malaria since 2015 (from 211 million in 2015 to 229 million in 2019). This trend could partially be due to the development of resistance to all the current drugs. Therefore, there is an urgent need for new alternatives. We have, thus, selected common natural scaffolds, polyhydroxybenzoic acids, and synthesized a library of derivatives to better understand the structure–activity relationships explaining their antiplasmodial effect. Only gallic acid derivatives showed a noticeable potential for further developments. Indeed, they showed a selective inhibitory effect on Plasmodium (IC50 ~20 μM, SI > 5) often associated with interesting water solubility. Moreover, this has confirmed the critical importance of free phenolic functions (pyrogallol moiety) for the antimalarial effect. Methyl 4-benzoxy-3,5-dihydroxybenzoate (39) has, for the first time, been recognized as a potential lead for future research because of its marked inhibitory activity against Plasmodium falciparum and its significant hydrosolubility (3.72 mM).
Method of preparing high-purity propyl gallate by stepwise catalysis
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Paragraph 0033-0072, (2019/03/31)
The invention provides a method of preparing high-purity propyl gallate by stepwise catalysis. The method comprises the step of subjecting gallic acid and n-propanol as raw materials to reaction underthe catalytic action of perchloric acid and sulfamic acid or under the catalytic action of p-toluenesulfonic acid and sulfamic acid to obtain propyl gallate. Testing shows that propyl gallate synthesized via the method meets the quality requirements in pharmacopoeia 2015 version, and is up to 99.9% and above in purity, with no gallic acid impurity peak detected.