<scp>l</scp>-Tyrosine loaded nanoparticles: an efficient catalyst for the synthesis of dicoumarols and Hantzsch 1,4-dihydropyridines

Khaskel, Anamika; Barman, Pranjit; Jana, Utpal

doi:10.1039/c4ra16627b

Cited by 17 publications

(6 citation statements)

References 33 publications

(14 reference statements)

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“…Tyrosine, Curcurmin and Epigallocatechin gallate have different number of phenol structures and classified as monophenol, biphenol and polyphenols, respectively. These ligands act as reducing and stabilizing agents in NP synthesis [36] and are widely studied for different applications [17,42,82] including therapeutic applications where their organic nature makes them biocompatible [20,27]. Despite increasing usage, comparative studies on effects of NPs coated with different organic coatings on aquatic organisms are relatively scarce.…”

Section: Introductionmentioning

confidence: 99%

The toxicity of coated silver nanoparticles to the alga Raphidocelis subcapitata

et al. 2020

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The use of silver nanoparticles (AgNPs) is growing exponentially, especially in consumer products due to their excellent antimicrobial properties. However, concerns are growing on their possible negative effects on environmental and human health. AgNPs from consumer products enter aquatic ecosystems where their physicochemical properties including surface functionalization are critical to their impact on aquatic organisms. The effects of AgNPs coated with three different ligands; tyrosine (T-AgNP), epigallocatechin gallate (E-AgNP) and curcumin (C-AgNP) and Ag + ions on the freshwater green alga Raphidocelis subcapitata were investigated. Stability tests of AgNPs revealed that the coating significantly affects the fate and behaviour of AgNPs. All types of AgNPs tested and ionic silver were found to be toxic to the alga and differential growth inhibition of algae were observed from differently coated AgNPs, with the 48 h EC 50 of C-AgNPs, T-AgNPs and E-AgNPs being 0.155, 0.163 and 0.243 mg L −1 , respectively, in comparison with 0.051 mg L −1 for Ag + ions. Associated Ag in the algae increased with increased concentrations of all AgNPs and Ag + ions and the toxicity positively correlated to the associated Ag content in algae. The antioxidant enzymes glutathione S-transferase and catalase were activated in algal cells by the AgNPs and Ag + ions, but a consistent difference in response was not identified with different concentrations of NPs. This study shows the effects of the surrounding environment and surface functionalization of AgNPs on algae highlighting the importance of considering them in environmental risk assessment of AgNPs.

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Section: Introductionmentioning

confidence: 99%

The toxicity of coated silver nanoparticles to the alga Raphidocelis subcapitata

et al. 2020

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“…However, the requirement for biocompatible capping agents, especially in the pharmaceutical industry (Duse et al 2017), has resulted in the development and use of several organic-based materials (biomasses or extracts) as capping agents in producing NPs (Rodríguez-León et al 2013;Sapsford et al 2013). The capping agents which were used to synthesize AgNPs in the present study were tyrosine (T-AgNP), epigallocatechin gallate (E-AgNP), and curcumin (C-AgNP; Nune et al 2009;El Khoury et al 2015;Khaskel et al 2015;Contino et al 2016).…”

Section: Introductionmentioning

confidence: 99%

The Toxicity of Nonaged and Aged Coated Silver Nanoparticles to Freshwater Alga Raphidocelis subcapitata

Lekamge

Miranda

Trestrail

et al. 2019

Enviro Toxic and Chemistry

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The transformation of coated silver nanoparticles (AgNPs) and their impacts on aquatic organisms require further study. The present study investigated the role of aging on the transformation of differently coated AgNPs and their sublethal effects on the freshwater alga Raphidocelis subcapitata. The stability of AgNPs was evaluated over 32 d, and the results indicated that transformation of AgNPs occurred during the incubation; however, coating‐specific effects were observed. Fresh AgNPs increased reactive oxygen species (ROS) formation, whereas aged AgNPs induced excessive ROS generation compared with their fresh counterparts. Increased ROS levels caused increased lipid peroxidation (LPO) in treatment groups exposed to both fresh and aged NPs, although LPO was comparatively higher in algae exposed to aged AgNPs. The observed increase in catalase (CAT) activity of algal cells was attributed to early stress responses induced by excessive intracellular ROS generation, and CAT levels were higher in the aged NP treatment groups. In conclusion, AgNPs increased ROS levels and LPO in algae and caused the activation of antioxidant enzymes such as CAT. Overall, the results suggest that aging and coating of AgNPs have major impacts on AgNP transformation in media and their effects on algae. Environ Toxicol Chem 2019;38:2371–2382. © 2019 SETAC

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“…While the reaction can be traditionally effected with protonic or Lewis acidic catalysts, there have been an urgent need to develop new and efficient catalytic systems to perform this transformation. In this regard plenty of representative catalysts have been developed for Hantzsch reaction, including LiBr, sulfated polyborate, Fe‐TUD‐1, PPA‐SiO 2 , nanoZnO, BiBr 3 , MOFs,, Cu‐NP/C, nano‐γ‐Fe 2 O 3 ,, LTNPs, [Ru(bpy) 3 ] 2+ , and others . However, despite the efficiency of these protocols, most of them still suffer from problems including cumbersome operation and corrosive environment.…”

Section: Methodsmentioning

confidence: 99%

Novel and Effective Strategy of Multifunctional Titanium Incorporated Mesoporous Material Supported Ionic Liquid Mediated Reusable Hantzsch Reaction

et al. 2019

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Mesoporous material supported functionalized ionic liquids have been designed and synthesized, characterized and evaluated as novel heterogeneous catalysts for the Hantzsch reaction. The as-fabricated catalysts show good performance in the Hantzsch synthesis of 1,4-dihydropyridines under ambient conditions, especially the titanium incorporated mesoporous material supported ionic liquid Ti-SBA-15@IL-BF 4 , based on a synergetic effect of titanium site of mesoporous material carrier and the acidic sites of ionic liquid. In addition, the heterogeneous catalyst offers simple operation for recovery and the recycling test showed that it could be reused for five times without significant loss of catalytic activity.

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l-Tyrosine loaded nanoparticles: an efficient catalyst for the synthesis of dicoumarols and Hantzsch 1,4-dihydropyridines

Abstract: l-Tyrosine loaded nanoparticles catalyzed organic reactions.

Cited by 17 publications

References 33 publications

The toxicity of coated silver nanoparticles to the alga Raphidocelis subcapitata

The toxicity of coated silver nanoparticles to the alga Raphidocelis subcapitata

The Toxicity of Nonaged and Aged Coated Silver Nanoparticles to Freshwater Alga Raphidocelis subcapitata

Novel and Effective Strategy of Multifunctional Titanium Incorporated Mesoporous Material Supported Ionic Liquid Mediated Reusable Hantzsch Reaction

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