- Characterization of Aspergillus fumigatus CAS-21 tannase with potential for propyl gallate synthesis and treatment of tannery effluent from leather industry
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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.
- Cavalcanti, Rayza Morganna Farias,Jorge, Jo?o Atílio,Guimar?es, Luis Henrique Souza
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- Development of a tannase biocatalyst based on bio-imprinting for the production of propyl gallate by transesterification in organic media
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A bio-imprinting technique was applied to activate tannase in order to enhance its biocatalytic activity. Specifically, the effects of three bio-imprinting methods (i.e. substrate imprinting, pH imprinting, and interfacial imprinting) on the activating factor of tannase were investigated. The results show that bio-imprinting methods can activate tannase remarkably, and they were combined to develop a tannase biocatalyst with a 40% conversion rate of substrate, 100-fold higher than that of the control. This approach can be used to construct an effective way to produce propyl gallate as well as to exploit readily available tannic acid. The immobilized bio-imprinted tannase can catalyze the synthesis of propyl gallate from tannic acid by transesterification in organic media. This work not only presents an effective means of making use of various tannic acid-rich agro-forestry residues, but also broadens the field of applications of the bio-imprinting technique.
- Nie, Guangjun,Zheng, Zhiming,Jin, Wei,Gong, Guohong,Wang, Li
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- Enhancement of transesterification-catalyzing capability of bio-imprinted tannase in organic solvents by cryogenic protection and immobilization
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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.
- Nie, Guangjun,Chen, Zhen,Zheng, Zhiming,Jin, Wei,Gong, Guohong,Wang, Li,Yue, Wenjin
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- Role of cyclic alkyl group in conformational instability of tannase
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The conformational stability of enzyme has a crucial effect on its catalytic performance. The effects of six organic solvents with different structures on the conformational stability of tannase were studied using Fourier transform infrared spectroscopy in this work. This results indicated that the cyclic structure of organic solvent plays a negative role in the conformational stability of tannase. The alkyl group of organic solvent has an interaction with the groups of oxygen and nitrogen of tannase, and the interaction goes against the conformational stability. The findings potentially provide a deep insight into the relationship between the biocatalytic activity and conformational stability of enzymes and push the study on the interaction of enzyme with organic solvent.
- Nie, Guangjun,Zhao, Rui,Sun, Wuyue,Gao, Yu,Zhu, Xiangxiang,Zheng, Zhiming,Yue, Wenjin
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- Self-assembled tetramethyl cucurbit[6]uril-polyoxometalate nanocubes as efficient and recyclable catalysts for the preparation of propyl gallate
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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.
- Li, Shuang,Xia, Wen,Zhang, Yunqian,Tao, Zhu
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- Thermodynamics of the hydrolysis of 3,4,5-trihydroxybenzoic acid propyl ester (n-propylgallate) to 3,4,5-trihydroxybenzoic acid (gallic acid) and propan-1-ol in aqueous media and in toluene
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Equilibrium measurements at several temperatures between 293 K and 308 K have been performed on the tannase catalyzed reaction : 3,4,5-trihydroxybenzoic acid propyl ester(sln) + H2O(sln) = 3,4,5-trihydroxybenzoic acid(sln) + propan-1-ol(sln), where sln = aqueous phosphate buffer, aqueous acetate buffer, and toluene. The change in binding of the hydrogen ion ΔrN(H+) for this biochemical reaction in aqueous solution was calculated both from an equilibrium model for the biochemical reaction and from the dependence of the apparent equilibrium constant on pH. Calorimetric measurements were also performed for this biochemical reaction in aqueous phosphate and 2-(N-morpholino)ethanesulfonic acid (MES) buffers. Standard transformed thermodynamic quantities for the overall biochemical reaction as well as standard thermodynamic quantities for chemical reference reactions that involve specific chemical species have been calculated from the experimental results. It was found that the equilibrium yield of 3,4,5-trihydroxybenzoic acid propyl ester is significantly enhanced by carrying out the reaction in toluene rather than in the aqueous buffered solutions.
- Tewari,Schantz,Rekharsky,Goldberg
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- Synthesis of propyl gallate from tannic acid catalyzed by tannase from Aspergillus oryzae: Process optimization of transesterification in anhydrous media
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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.
- Nie, Guangjun,Liu, Hui,Chen, Zhen,Wang, Peng,Zhao, Genhai,Zheng, Zhiming
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- Enhancement of propyl gallate yield in nonaqueous medium using novel cell-associated tannase of bacillus massiliensis
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Enzymatic synthesis of propyl gallate in organic solvent was studied using cell-associated tannase (EC 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as the biocatalyst. The effects of solvent, surfactant treatment, and bioimprinting on the propyl gallate synthesis were studied and subsequently optimized. Among various solvents, benzene followed by hexane was found to be the most favorable. Treatment of the biocatalyst with Triton X-100 at a lower concentration (0.2% w/v), before lyophilization, increased the propyl gallate yield by 24.5% compared to the untreated biocatalyst. The biocatalyst was imprinted with various concentrations of gallic acid and tannic acid. Biocatalyst imprinted with tannic acid showed 50% enhancement in the propyl gallate yield compared to the non-imprinted biocatalyst.
- Aithal, Mahesh,Belur, Prasanna D.
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- Potentiation of vasoconstrictor response and inhibition of endothelium-dependent vasorelaxation by gallic acid in rat aorta
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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.
- Sanae, Fujiko,Miyaichi, Yukinori,Hayashi, Hisao
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- Enzymatic propyl gallate synthesis in solvent-free system: Optimization by response surface methodology
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The ability of a non-commercial immobilized Staphylococcus xylosus lipase to catalyze the esterification of propanol with gallic acid was investigated and the antioxidant as well as the antimicrobial activities of the ester formed were evaluated. The response surface methodology, based on a three variables Box-Behnken design (reaction temperature, enzyme amount and 1-propanol/gallic acid molar ratio), was used to optimize the experimental conditions of propylgallate synthesis. The maximum conversion yield (90% ±3.5) was obtained by using 400 IU of immobilized lipase and a propanol/gallic acid at a molar ratio of 160 at 52 °C. The obtained ester was characterized by spectroscopic methods, NMR and FTIR. The antioxidant activity of propyl gallate was evaluated and compared to the synthetic classical antioxidants, BHA and ascorbic acid, taken as references. In addition, the antimicrobial activity of the propyl gallate was tested against S. xylosus, Escherchia coli and Staphylococcus aureus using disc diffusion and macrodilution methods. Our results show that the synthesized propyl gallate ester presents a higher antioxidant and antimicrobial power than the parent gallic acid as well as the synthetic classical antioxidants.
- Bouaziz, Ahlem,Horchani, Habib,Salem, Nadia Ben,Chaari, Ali,Chaabouni, Moncef,Gargouri, Youssef,Sayari, Adel
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- Synthesis of propyl gallate by transesterification of tannic acid in aqueous media catalysed by immobilised derivatives of tannase from Lactobacillus plantarum
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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.
- 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.
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- A recyclable cucurbit[6]uril-supported silicotungstic acid catalyst used in the esterification reaction
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The esterification reaction used to prepare butyl paraben (BP) and propyl gallate (PG) catalyzed using a cucurbit[6]uril-supported Keggin-type silicotungstic acid (Q[6]-STA) catalyst has been investigated. The Q[6]-STA catalyst has been characterized using FTIR spectroscopy, XRD, SEM, EDS, thermal analysis, and surface area studies. Q[6]-STA was easy to prepare in high yield and exhibited some advantageous properties, such as high catalytic activity and its convenient recovery. Moreover, a reusability study showed that the Q[6]-STA catalyst was stable and active.
- Xia, Wen,Nie, Yu-Mei,Lei, Na,Tao, Zhu,Zhu, Qiang-Jiang,Zhang, Yun-Qian
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- Polyhydroxybenzoic acid derivatives as potential new antimalarial agents
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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).
- Degotte, Gilles,Francotte, Pierre,Pirotte, Bernard,Frédérich, Michel
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- A preparation method of electronic grade gallic octyl ester
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The present invention provides a kind of electronic grade gallic octyl ester of preparation method, which belongs to the technical field of organic synthesis. The gallic acid dissolved in alcohol, then drop adds the chlorination [...], then adding aromatic hydrocarbon solvent, a catalytic amount of B (C6F5) 3 and octanol, moiety will be distillation after the exchange, getting the gallic octyl ester. This method avoids the use of heavy metal catalyst, high yield, low cost, and is suitable for industrial scale production, the ester exchange after the end of the added metal ion adsorbent after the metal ion adsorption, distillation electronic level of gallic octyl ester.
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Paragraph 0023; 0024; 0034; 0035; 0036
(2019/03/31)
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- Method of preparing high-purity propyl gallate by stepwise catalysis
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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.
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Paragraph 0033-0072
(2019/03/31)
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- Gallate-induced nanoparticle uptake by tumor cells: Structure-activity relationships
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How nanoparticles interact with biological systems determines whether they can be used in theranostic applications. It has been demonstrated that tea catechins, may enhance interactions of magnetic nanoparticles (MNPs) with tumor cells and the subsequent cellular internalization of MNPs. As part of the chemical structure of the major tea catechins, gallates are found in a variety of plants and thus food components. We asked whether the structure of gallate might act as a pharmacophore in the enhancement of the effects of MNP-cell interactions. Uptake of dextran-coated MNPs by glioma cells and cell-associated MNPs (MNPcell) were respectively analyzed by confocal microscopy and a colorimetric iron assay. Co-incubation of MNPs and gallates, such as gallic acid and methyl gallate, induced a concentration-dependent increase in MNPcell, which was associated with co-localization of internalized MNPs and lysosomes. An analysis of the structure-activity relationship (SAR) revealed that the galloyl moiety exerted the most prominent enhancement effects on MNPcell which was further potentiated by the application of magnetic force; catechol coupled with a conjugated carboxylic acid side chain displayed comparable effects to gallate. Blockade or reduction in the number of hydroxyl groups rendered these compounds less effective, but without inducing cytotoxicity. The SAR results suggest that neighboring hydroxyl groups on the aromatic ring form an essential scaffold for the uptake effects; a similar SAR on antioxidant activities was also observed using a free radical-scavenging method. The results provide pivotal information for theranostic applications of gallates by facilitating nanoparticle-cell interactions and nanoparticle internalization by tumor cells.
- Cheng, Min-Chi,Lu, Yi-Ching,Wu, Jender,Ma, Yunn-Hwa
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- Synthesis and evaluation of novel benzotropolones as Atg4B inhibiting autophagy blockers
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Autophagy is an intracellular degradation/recycling pathway that provides nutrients and building blocks to cellular metabolism and keeps the cytoplasm clear of obsolete proteins and organelles. During recent years, dysregulated autophagy activity has been reported to be a characteristic of many different disease types, including cancer and neurodegenerative disorders. This has created a strong case for development of autophagy modulating compounds as potential treatments for these diseases. Inhibitors of autophagy have been proposed as a therapeutic intervention in, e.g., advanced cancer, and inhibiting the cysteine protease Atg4B has been put forward as a main strategy to block autophagy. We recently identified and demonstrated -both in vitro and in vivo - that compounds with a benzotropolone basic structure targeting Atg4B, can significantly slow down tumor growth and potentiate the effect of classical chemotherapy. In this study we report the synthesis and inhibition profile of new benzotropolone derivatives with additional structural modifications at 6 different positions. To obtain a solid inhibition profile, all compounds were evaluated on three levels, including two cell-based assays to confirm autophagy and intracellular Atg4B inhibition and an SDS-PAGE-based experiment to assess in vitro Atg4B affinity. Several molecules with a promising profile were identified.
- Tanc, Muhammet,Cleenewerck, Matthias,Kurdi, Ammar,Roelandt, Ria,Declercq, Wim,De Meyer, Guido,Augustyns, Koen,Martinet, Wim,Van der Veken, Pieter
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p. 163 - 168
(2019/03/19)
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- METHOD FOR ENHANCING DELIVERY OF THERAPEUTIC DRUGS TO TREATMENT SITES
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Disclosed herein is a method for enhancing uptake of magnetic nanoparticles (MNPs) having a therapeutic agent associated therein to a target site (e.g., a tumor), thereby resulting in elevated level of therapeutic agents being accumulated in the target site. The method comprises concurrently administering a sufficient amount of a polyphenolic compound and MNPs to the target site. Also disclosed herein is a method for treating a cancer in a subject. The method comprises concurrently administering an effective amount of the polyphenolic compound and MNPs to the subject, so as to ameliorate or alleviate symptoms associated with the cancer.
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Paragraph 0132-0134
(2019/05/18)
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- HALOGENATED BENZOTROPOLONES AS ATG4B INHIBITORS
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The present invention relates to compounds having a benzotropolone core, and compositions containing said compounds acting as ATG4B inhibitors, thereby inhibiting autophagy. Moreover, the present invention provides processes for the preparation of the disclosed compounds, as well as methods of using them, for instance as a medicine, in particular for the treatment of cell proliferative disorders, such as cancer.
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Page/Page column 33; 40; 41
(2018/06/12)
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- Synthesis and biological evaluation of novel gallic acid analogues as potential antimicrobial and antioxidant agents
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A series of fifteen novel gallic acid esters (7a-o) was synthesized and structure was confirmed by spectral data. Antibiotic power of compounds was assessed against a panel of ten microbes while antioxidant activity was gauged by employing DPPH, ABTS and antilipid peroxidation assays. It was found that in comparison to lead, many of the synthesized derivatives implied much improved broad spectrum antimicrobial effect. Most effective compound found was 7c specifically against resistant gram-negative strains such as P.aeruginosa, E.coli and E.aerogenes. Potent antioxidant capacity was exhibited by7a and 7d in electron transfer assays while 7j and 7c provided maximum shielding against lipid peroxidation. Structure-activity analysis revealed that analogues with electron -withdrawing substituent particularly chloro group stand out as much better antibiotic agent. This study suggests that halogenated gallic acid analogues might be promising pharmacological candidates in view of further drug development.
- Sherin, Lubna,Shujaat, Shahida,Sohail, Ayesha,Arif, Fatima
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p. 551 - 565
(2019/04/17)
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- Synthesis and in vitro antimalarial activity of alkyl esters of gallate as a growth inhibitor of plasmodium falciparum
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This study is aimed to synthesize alkyl esters gallate and determine its in vitro antimalarial activity against parasite Plasmodium falciparum. Fourteen compounds of alkyl esters gallate were synthesized by esterification of the carboxyl group of gallic acid with a series of alkyl alcohols, as well as methoxylation of the hydroxy groups on the aromatic ring of gallic acid. Antimalarial activity of the synthesized alkyl esters gallate were expressed by IC50 value, with gallic acid as an original compound and artemisin as a positive control. Compared to gallic acid, eleven synthesized compounds of alkyl esters gallate, have a greater antimalarial activity against Plasmodium falciparum. On the other hand, three compounds, that are propyl gallate, butyl gallate and trimethoxy methyl gallate, showed a lower antimalarial activity. Moreover, compared to gallic acid (IC50: 194.86 mM) and artemisin (IC50: 0.5 mM), two synthesized compounds of alkyl gallates, namely methyl gallate and hexyl gallate exhibited the stronger antimalarial activity against Plasmodium falciparum, with IC50 value of 0.03 mM and 0.11 mM, respectively. Our result clearly demonstrated that methyl gallate and hexyl gallate as a promising candidate for the new antimalarial agents.
- Arsianti, Ade,Astuty, Hendri,Fadilah,Simadibrata, Daniel Martin,Adyasa, Zoya Marie,Amartya, Daniel,Bahtiar, Anton,Tanimoto, Hiroki,Kakiuchi, Kiyomi
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p. 655 - 662
(2018/05/28)
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- Method for catalytic synthesis of gallic acid propyl ester from solid acid
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The invention relates to a method for catalytic synthesis of a gallic acid propyl ester from a solid acid. The method is characterized by comprising the following steps: mixing a gallic acid with normal propyl alcohol, stirring, heating to 50 DEG C, adding a catalysis amount of a mordenite molecular sieve based catalyst, continuously heating to 70 DEG C to backflow temperature, performing a reaction for 3-5 hours, filtering off the mordenite molecular sieve based catalyst, and performing vacuum concentration on filtrate, thereby obtaining the gallic acid propyl ester.
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Paragraph 0042; 0043; 0045; 0053
(2018/01/09)
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- Synthetic method of gallic acid lower alkanol ester
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A synthetic method of gallic acid lower alkanol ester comprises the following steps of: (1) placing gallic acid and lower alkanol in a reactor, adding a sulfonic acid resin catalyst subjected to hydrophobic modification, carrying out stirring, heating to a temperature of 65 to 120 DEG C, performing the reaction for 4 to 10h and filtering to obtain filtrate; (2) removing excessive alcohol in the filtrate by evaporation so as to obtain a crude product, then carrying out recrystallization by deionized water, and carrying out suction filtration and drying to obtain the gallic acid lower alkanol ester. The synthetic method disclosed by the invention is simple, is safe to operate; yield of the gallic acid lower alkanol ester is greater than or equal to 92 percent; product purity is more than or equal to 99.5 percent; moreover, the catalyst has excellent performance; the water distribution link in a conventional method is reduced; a reaction apparatus is simplified; the synthetic method has good repeatability.
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Paragraph 0028
(2017/01/12)
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- Preparation method for propyl gallate
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The invention relates to a preparation method for propyl gallate, belonging to the technical field of preparation of food additives. The method mainly comprises the following steps: subjecting fresh leaves of Evodiae to pretreatment and then mixing the pretreated leaves with alcohol; adding cellulase and pectase and carrying out heating and mixing under stirring; mixing a material obtained after enzyme deactivation and reflux extraction with calcium oxide; carrying out heating, evaporation to dryness and cooling; then carrying out heating and using filter paper for adsorption at the same time so as to obtain gallic acid crystal; subjecting the gallic acid crystal, citric acid, n-propanol and other substances to ball milling; and subjecting a material obtained in the previous step to concentration, refrigeration, filtering and the like so as to obtain propyl gallate. The propyl gallate prepared in the invention is high in yield, reaching 98% or above, and no by-product is produced in the process of preparation; and the method does not produce pollutants to pollute environment and is environment-friendly.
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Paragraph 0009
(2017/01/17)
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- COMBINATION OF COMPOUNDS DERIVED FROM GALLIC ACID FOR THE TREATMENT OF CANCER
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The invention relates to a combination of compounds derived from gallic acid, with an antitumoral and antimetastatic activity via a mechanism that involves the induction of apoptosis and the immunogenic death of the tumour cells and the subsequent activation of the specific immune response. The invention also relates to a composition containing a combination of derivatives of gallic acid and pharmaceutically acceptable excipients for the production of useful medicaments in the treatment of cancer. The invention further relates to the use of said composition in a coadjuvant in conventional chemotherapy, reducing the doses of chemptherapeutic agents used in the treatment of cancer.
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- Microwave-assisted esterification of gallic acid
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An efficient synthesis of alkyl gallates under microwave irradiation was described. The reaction took place in 6-10 mins, which was much shorter than the traditional synthetic methods, with almost quantitative yields.
- Shi, Zhi-Hao,Li, Nian-Guang,Tang, Yu-Ping,Shi, Qian-Ping,Zhang, Wei,Zhang, Peng-Xuan,Li, Wei,Dong, Ze-Xi,Duan, Jin-Ao
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p. 1351 - 1354
(2016/06/13)
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- Antifungal activity of alkyl gallates against plant pathogenic fungi
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The antifungal activity of alkyl gallates against plant pathogenic fungi was evaluated. All of the fungi tested in this study were susceptible to some alkyl gallates, and the effect of linear alkyl gallates against plant pathogenic fungi was similar to the previously reported effects against Gram-negative and Gram-positive bacteria. We found that branched alkyl gallates showed stronger activity than did linear alkyl gallates with similar log P values. In addition, the antifungal activity of alkyl gallates was correlated with gallate-induced inhibition of the activity of mitochondrial complex II. The antifungal activity of alkyl gallates likely originates, at least in part, from their ability to inhibit the membrane respiratory chain.
- Ito, Shinsaku,Nakagawa, Yasutaka,Yazawa, Satoru,Sasaki, Yasuyuki,Yajima, Shunsuke
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p. 1812 - 1814
(2014/04/17)
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- Alkyl hydroxybenzoic acid derivatives that inhibit HIV-1 protease dimerization
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The therapeutic potential of gallic acid and its derivatives as anti-cancer, antimicrobial and antiviral agents is well known. We have examined the mechanism by which natural gallic acid and newly synthesized gallic acid alkyl esters and related protocatechuic acid alkyl esters inhibit HIV-1 protease to compare the influence of the aromatic ring substitutions on inhibition. We used Zhang-Poorman's kinetic analysis and fluorescent probe binding to demonstrate that several gallic and protecatechuic acid alkyl esters inhibited HIV-1 protease by preventing the dimerization of this obligate homodimeric aspartic protease rather than targeting the active site. The tri-hydroxy substituted benzoic moiety in gallates was more favorable than the di-substituted one in protocatechuates. In both series, the type of inhibition, its mechanism and the inhibitory efficiency dramatically depended on the length of the alkyl chain: no inhibition with alkyl chains less than 8 carbon atoms long. Molecular dynamics simulations corroborated the kinetic data and propose that gallic esters are intercalated between the two N- and C-monomer ends. They complete the β-sheet and disrupt the dimeric enzyme. The best gallic ester (14 carbon atoms, Kid of 320 nM) also inhibited the multi-mutated protease MDR-HM. These results will aid the rational design of future generations of non-peptide inhibitors of HIV-1 protease dimerization that inhibit multi-mutated proteases. Finally, our work suggests the wide use of gallic and protocatechuic alkyl esters to dissociate intermolecular β-sheets involved in protein-protein interactions.
- Flausino Jr., O. A.,Dufau, L.,Reboud-Ravaux, M.,Regasini, L. O.,Petronio, M. S.,Silva, D. H. S.,Bolzani, V. S.,Rose, T.
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p. 4534 - 4540,7
(2012/12/12)
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- Suppression of TNF-α induced NFκB activity by gallic acid and its semi-synthetic esters: Possible role in cancer chemoprevention
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Gallic acid (3,4,5-trihydroxybenzoic acid), found in many plants either in free-form or part of tannins, is known to possess anti-microbial, antioxidant and cytotoxic properties. NFκB regulates the expression of several genes involved in carcinogenesis. These include anti-apoptotic, cytokines and cell cycle-regulatory genes. It is well established that the transcriptional factor NFκB is deregulated in many forms of cancer. Thus, agents that can suppress NFκB activation have the potential of suppressing carcinogenesis. In the present investigation, gallic acid was isolated from Alchornea glandulosa (Euphorbiaceae) and eight esters were synthesised. These compounds were evaluated against TNF-α-induced NFκB activation with stably transfected 293/NFκB-Luc human embryonic kidney cells. Gallates with IC50 values in a range of 10-56 M mediated inhibitory activity higher than gallic acid (IC50 76.0 4.9 M). In addition to inhibiting NFκB activation, gallic acid mediated a modest cytotoxic effect, and some of the gallates affected cell viability at the tested concentrations. Based on these results, suppression of NFκB activation by gallate esters could play a chemopreventive role in carcinogenesis.
- Morais, Mauro C. C.,Luqman, Suaib,Kondratyuk, Tamara P.,Petronio, Maicon S.,Regasini, Luis O.,Silva, Dulce H. S.,Bolzani, Vanderlan S.,Soares, Christiane P.,Pezzuto, John M.
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experimental part
p. 1758 - 1765
(2011/01/12)
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- Inhibitory effect of gallic acid and its esters on 2,2'-azobis(2- amidinopropane)hydrochloride (AAPH)-induced hemolysis and depletion of intracellular glutathione in erythrocytes
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The protective effect of gallic acid and its esters, methyl, propyl, and lauryl gallate, against 2,2'-azobis(2-amidinopropane)hydrochloride (AAPH)-induced hemolysis and depletion of intracellular glutathione (GSH) in erythrocytes was studied. The inhibition of hemolysis was dose-dependent, and the esters were significantly more effective than gallic acid. Gallic acid and its esters were compared with regard to their reactivity to free radicals, using the DPPH and AAPH/pyranine free-cell assays, and no significant difference was obtained. Gallic acid and its esters not only failed to inhibit the depletion of intracellular GSH in erythrocytes induced by AAPH but exacerbated it. Similarly, the oxidation of GSH by AAPH or horseradish peroxidase/H 2O2 in cell-free systems was exacerbated by gallic acid or gallates. This property could be involved in the recent findings on pro-apoptotic and pro-oxidant activities of gallates in tumor cells. We provide evidence that lipophilicity and not only radical scavenger potency is an important factor regarding the efficiency of antihemolytic substances.
- Ximenes, Valdecir F.,Lopes, Mariana G.,Petronio, Maicon Segalla,Regasini, Luis Octavio,Siqueira Silva, Dulce H.,Da Fonseca, Luiz M.
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experimental part
p. 5355 - 5362
(2011/08/05)
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- Evaluation of anti-herpetic and antioxidant activities, and cytotoxic and genotoxic effects of synthetic alkyl-esters of gallic acid
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The n-alkyl esters of gallic acid (CAS 138-57-8) have a diverse range of uses as anti-oxidants in food, cosmetics and pharmaceutical industries. Pharmaceutical studies performed with these compounds have found that they have many therapeutic potentialities including anti-cancer, antiviral and antimicrobial properties. However, more interest has been devoted to their antioxidant activity due to the ability to scavenge and reduce reactive oxygen species (ROS) formation. In this study, gallic acid and 14 different alkyl gallates were tested. The cytotoxicity and anti-herpetic (HSV-1, KOS and 29-R strains) activity were studied by using the MTT (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) colorimetric assay and the cell viability by using the Trypan blue dye exclusion method. The genotoxicity was studied by the Comet assay and the antioxidant activity by using the DPPH (1,1-diphenyl-2- picrylhydrazyl) radical scavenging and microsomal lipid peroxidation-inhibiting activities. The results showed that all the tested compounds have anti-herpetic activity at non cytotoxic concentrations with selectivity indices (SI = CC 50/EC50) varying from 0.89 to 18.34, depending on the used HSV-1 strain. It was observed that all tested alkyl gallates showed some degree of genotoxicity, at the tested concentrations, except cetyl gallate, at 256.60 μmol/L (p 50 values varying from 17 to 31 μmol/L; and microsomal lipid peroxidation-inhibiting activity with IC50 values varying from 21 to 59 μmol/L. It was observed that the presence of hydroxyl groups in these molecules is important for their pharmacological profile, but the length of the lateral carbonic chain does not have considerable influence.
- Savi, Luciane A.,Leal, Paulo C.,Vieira, Tiago O.,Rosso, Rober,Nunes, Ricardo J.,Yunes, Rosendo A.,Creczynski-Pasa, Tania B.,Barardi, Celia R. M.,Simoes, Claudia Maria Oliveira
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- Methods for sterilizing tissue
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Methods are disclosed for sterilizing tissue to reduce the level of one or more active biological contaminants or pathogens therein, such as viruses, bacteria, (including inter- and intracellular bacteria, such as mycoplasmas, ureaplasmas, nanobacteria, chlamydia, rickettsias), yeasts, molds, fungi, prions or similar agents responsible, alone or in combination, for TSEs and/or single or multicellular parasites. The methods involve sterilizing one or more tissues with irradiation.
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- Antifungal activity of octyl gallate: Structural criteria and mode of action
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Octyl gallate (3,4,5-trihydroxybenzoate) was found to possess antifungal activity against Saccharomyces cerevisiae and Zygosaccharomyces bailii, in addition to its potent antioxidant activity. Catechol moiety is essential to elicit this activity. The primary fungicidal activity of octyl gallate comes from its ability to act as a nonionic surface-active agent (surfactant). The length of the alkyl chain is not a major contributor but plays an important role in eliciting the activity.
- Kubo, Isao,Xiao, Ping,Fujita, Ken'ichi
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p. 347 - 350
(2007/10/03)
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- Cosmetic and cosmeceutical compositions
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PCT No. PCT/IL96/00135 Sec. 371 Date Feb. 5, 1999 Sec. 102(e) Date Feb. 5, 1999 PCT Filed Oct. 30, 1996 PCT Pub. No. WO97/16155 PCT Pub. Date May 9, 1997Cosmetic and cosmeceutical compositions which enhance repair of damage caused to human DNA caused by excessive exposure to sunlight or to other radiation causing such damage. The active ingredients are a synergistic combination of nor-dihydroguiaretic acid (NDGA) and niacinamide. Optional components are propyl gallate or other antioxidants. Composition may further contain sun-screen additives.
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- Coagulation assays and reagents
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Novel assays and reagents for determining coagulative properties of blood or plasma are disclosed, as are agents and methods for stemming bleeding. Novel ellagic acid-based activators consist essentially of aqueous solutions of ellagic acid, phenol and suitable metal ions and give defined values for a novel platelet assay also disclosed. Inventive coagulation reagents including propyl gallate or tannin are also disclosed, as are aPTT reagents having sensitivity to heparin and Factor deficiencies far superior to prior aPTT reagents. Disclosed heparin-sensitive reagents include dextran sulfate. Also disclosed is applicant's discovery that reagents including hydroxy-substituted compounds and metal ions, heretofore known to activate Hagemann Factor, also cause platelets to release Platelet Factor 3, and a series of platelet-sensitive tests found to be enabled by this discovery. These platelet-sensitive tests include assays for platelet activity, systemic lupus, platelet reserve, which can signify type II lipoprotein defects, and for Platelet Factor 4. Disclosed methods and materials for stemming bleeding center around applicant's discovery that bleeding from bleeding sites can be stopped up to six time faster by applying to the site a hemostatic agent including effective amounts of hydroxy-substituted aromatic compound and metal ion.
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- Preparation of alkyl gallates
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C1 -C20 -alkyl gallates are prepared by reacting tannin-containing material with the corresponding alcohol R--OH and a strong acid.
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- Antioxidant benzodioxole compound
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Novel antioxidant compounds for use in foodstuffs containing oils or fats are described which comprise benzodioxole compounds having the structure STR1 wherein R1 is a hydrogen atom or an alkyl group or an aryl group, R2 is an alkyl group or an aryl group, or R1 and R2 together form a cyclo alkyl group, and R3 is a hydrogen atom or an hydroxyl group.
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- Electron Transfer Reactions of Halothane-derived Peroxyl Free Radicals, CF3CHClO2.: Measurement of Absolute Rate Constants by Pulse Radiolysis
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The halothane-derived peroxyl radical CF3CHClO2. has been generated in aqueous solutions by pulse radiolysis.Absolute rate constants for the reduction of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) by hydrated electrons, hydrogen atoms, and propan-2-ol free radicals have been determined to be k 1.4E10, 3.8E8, and 7.6E7 l mol-1 s-1, respectively.The predominant product radical CF3CHCl rapidly adds O2, and an estimate of k 1.3E9 l mol-1 s-1, has been obtained for the absolute rate constant of this reaction.The resulting peroxyl radical CF3CHClO2. has been found to react rapidly with a variety of nucleophilic compounds such as 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate), the phenothiazines promethazine, chlorpromazine, and metiazinic acid, the vitamins C and E, and propyl gallate.The absolute rate constants for these reactions are found to be generally lower than for corresponding reactions of the carbon tetrachloride-derived radical, CCl3O2..
- Moenig, Joerg,Asmus, Klaus-Dieter,Schaeffer, Michel,Slater, Trevor F.,Willson, Robin L.
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p. 1133 - 1138
(2007/10/02)
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