Analysis of keto-enol tautomers of curcumin by liquid chromatography/mass spectrometry

Kawano, Seiji; Inohana, Yusuke; Hashi, Yuki; Lin, Jin‐Ming

doi:10.1016/j.cclet.2013.05.006

Cited by 54 publications

(45 citation statements)

References 17 publications

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“…The data from Table 2 135 8 and Figure 3 show that the addition of water stabilizes the diketo tautomer, leading to excess of it 136 in pure water if we roughly extrapolate the data ( Figure S1, ∆G 293K =-0.41 kcal/mol). The 137 reliability of the results is supported by the fact that in 50% water/50% ethanol the diketo forms 138 has substantial contribution, but the enol form is dominating as reported for 50% water/50% 139 acetonitrile mixture [31] investigated by LC-MS.…”

supporting

confidence: 62%

“…Finally, the existence of the diketo tautomer in water/acetonitrile mixtures has been proven by 125 Kawano et al [31] by using liquid chromatography/mass spectrometry. Taking into account that the spectrum of the diketo form is unknown and the spectrum of the 128 enol-keto form is strongly solvent dependent (see Figure 3a), it is difficult to estimate the content 129 of the tautomers by means of classical spectrophotometric analysis.…”

mentioning

confidence: 94%

“…During the centuries numerous 27 therapeutic activities have been assigned to turmeric for a wide variety of diseases and 28 conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, 29 wounds, sprains, and liver disorders [1]. Extensive research within the last half century has 30 proven that most of these activities, once associated with turmeric, are due to curcumin (1), 31 which gives its yellow color. Curcumin has been shown to exhibit antioxidant, anti- 32 inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a 33 potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, 34 and other chronic illnesses [1,2,3].…”

Section: Introductionmentioning

confidence: 99%

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The effect of the water on the curcumin tautomerism: A quantitative approach

Manolova

Deneva

Antonov

et al. 2014

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

185

135

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supporting

confidence: 62%

mentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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The effect of the water on the curcumin tautomerism: A quantitative approach

Manolova

Deneva

Antonov

et al. 2014

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

185

135

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“…3) were obtained for both synthetic and extracted curcumin, resp., and major peaks are presented in Table III. A computational approach determined that the enol form was more stable but this form does not influence the therapeutic properties of curcumin (15). 1 …”

Section: Extraction Of Curcuminmentioning

confidence: 99%

Curcumin: Synthesis optimization andin silicointeraction with cyclin dependent kinase

et al. 2017

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Curcumin: Synthesis optimization and in silico interaction with cyclin dependent kinaseCurcumin is a natural product with enormous biological potential. In this study, curcumin synthesis was revisited using different reaction solvents, a catalyst (n-butylamine) and a water scavenger [(n-BuO) 3 B], to develop the optimal procedure for its rapid acquisition. During synthesis, solvent choice was found to be an important parameter for better curcumin yield and high purity. In a typical reaction, acetyl acetone was treated with boron trioxide, followed by condensation with vanillin in the presence of tri-n-butyl borate as water scavenger and n-butylamine as catalyst at 80 °C in ethyl acetate to afford curcumin. Moreover, curcumin was also extracted from turmeric powder and spectroscopic properties such as IR, MS, 1 H NMR and 13 C NMR with synthetic curcumin were established to identify any impurity. The purity of synthetic and extracted curcumin was also checked by TLC and HPLC-DAD. To computationally assess its therapeutic potential against cyclin dependent kinases (CDKs), curcumin was docked in different isoforms of CDKs. It was observed that it did not dock at the active sites of CDK2 and CDK6. However, it could enter into weak interactions with CDK4 protein.Keywords: curcumin synthesis, CDKs, molecular docking Curcumin (C) is a phenolic compound that is considered to be a bioactive component of turmeric. Since ancient times it has been an integral part of ancient herbal medicine. Nowadays, it is widely used in medicine and in diet supplements. Structurally, curcumin exists in keto and enol tautomeric forms due to intra-molecular hydrogen bonding between keto carbonyl oxygen and an enolic hydrogen atom (1). Possible therapeutic potential of curcumin was revealed in the last decades. Different studies have explained its efficacy against various types of cancers such as chemo resistant colon cancer cells, esophageal cancers, thyroid carcinomas, skin cancer (2) and as a potent anti-inflammatory agent (3). Curcumin regulates various growth factors, protein kinases, inflammatory cytokines and transcription factors to suppress the metastases and proliferation of human tumors (4). Other than anticancer and antitumor activities, it has also shown its effects against a variety of diseases such as respiratory tract infection, hepatic steatosis, skin photoageing, Parkinson's disease, pathogenesis of obesity, diabetes, HIV-associated diarrhea and Alzheimer's disease, through inhibition of amyloid beta oligomer formation (5-8). The structure-activity relationship studies of curcumin molecule against different biological targets have indicated that the presence of two phenyl rings with a C-7 linker with ketoenol function (C=O groups as hydrogen acceptors and C-4 as a hydrogen donor) are most important for its biological activities. However, unsaturation in the linker (conformational flexibility) is important for its antitumor/anticancer activity but not for redox regulatory or apoptotic activities (9). Synthetic methodology to...

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“…Kawano et al used the MC-ODS column for LC-MS determination of drugs spiked in plasma and the method was of good precision, accuracy, and reproducibility [11]. Based on our previous works [11,12], we evaluated the on-line pretreatment LC-MS/MS system with the MC-ODS column to remove sugars in honey for minimizing sample pretreatment in this study.…”

Section: Introductionmentioning

confidence: 98%