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Dhenadhayalan N, Veeranepolian Selvi AS, Chellappan S, Thiagarajan V. Synergistic dynamics of photoionization and photoinduced electron transfer probed by laser flash photolysis and ultrafast fluorescence spectroscopy. Photochem Photobiol Sci 2021; 20:1109-1124. [PMID: 34427902 DOI: 10.1007/s43630-021-00084-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/02/2021] [Indexed: 11/24/2022]
Abstract
Photoionization (PI) and photoinduced electron transfer (PET) dynamics of coumarin 450 (C450) in micelles were investigated in the time domains of micro to femtoseconds using steady-state and time-resolved absorption and fluorescence spectroscopy. The PI of C450 occurs inside the micelles leads to the formation of C450 cation radical (CR) and hydrated electron, which is characterized by the respective transient absorption. The PI of C450 is monophotonic in nature and the yield is dependent on the charge of the micelles. The observation of amine CR in the transient absorption confirms the PET from amine to the excited state of C450 in micelles, which results in the quenching of both fluorescence intensity and lifetime. The decrease in femtosecond fluorescent decay of C450 and the absence of transient C450 radical anion in the presence of amine implies that the concerted ultrafast PET promoted PI and PET to the C450 CR-electron pair. The decrease in the time constant for the formation of relaxed state in the presence of amines is due to the ultrafast PET to the C450 CR-electron pair, which prevents the formation of a relaxed state through recombination at a longer time scale. In the present investigation, the recombination dynamics of the CR-electron pair is justified as one of the origins of the slow solvation in micelles. The influence of amine concentration on the decay of C450 CR indicates ET reaction between C450 CR and amine, which is further confirmed by the bleach recovery of C450 ground state in the presence of amine.
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Affiliation(s)
| | | | - Selvaraju Chellappan
- National Centre for Ultrafast Processes, University of Madras, Chennai, 600 113, India.
| | - Viruthachalam Thiagarajan
- Photonics and Biophotonics Lab, School of Chemistry, Bharathidasan University, Tiruchirappalli, 620 024, India. .,Faculty Recharge Programme, University Grants Commission, New Delhi, India.
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Bu M, Cao T, Li H, Guo M, Yang BB, Zeng C, Zhou Y, Zhang N, Hu L. Synthesis and biological evaluation of novel steroidal 5α,8α-epidioxyandrost-6-ene-3β-ol-17-(O-phenylacetamide)oxime derivatives as potential anticancer agents. Bioorg Med Chem Lett 2017; 27:3856-3861. [PMID: 28666736 DOI: 10.1016/j.bmcl.2017.06.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 06/18/2017] [Accepted: 06/19/2017] [Indexed: 02/03/2023]
Abstract
Inspired by the significant anti-cancer activity of our previously screened natural ergosterol peroxide (EP, 1), we synthesized and characterized a series of novel 5α,8α-epidioxyandrost-3β-ol-17-(O-phenylacetamide)oxime derivatives (9a-o). The anti-proliferative activity of the synthesized compounds against human hepatocellular carcinoma cells (HepG2, Sk-Hep1) and human breast cancer cells (MCF-7, MDA-MB231) were investigated. Compounds 9d, 9f, 9h, 9j and 9m displayed good anti-proliferative activity (most IC50<20μM) in vitro. Furthermore, fluorescence imaging showed that the designed coumarin-9d conjugate (12) localized mainly in mitochondria, leading to enhanced anticancer activities over the parent structure.
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Affiliation(s)
- Ming Bu
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China; College of Pharmacy, Qiqihar Medical University, Qiqihar 161006, China
| | - Tingting Cao
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Hongxia Li
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Mingzhou Guo
- Chinese PLA General Hospital, Beijing 100853, China
| | - Burton B Yang
- Sunnybrook Research Institute, University of Toronto, Toronto M4N3M5, Canada
| | - Chengchu Zeng
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Yue Zhou
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Na Zhang
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Liming Hu
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China; Beijing Key Laboratory of Environmental and Viral Oncology, Beijing University of Technology, Beijing 100124, China.
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Lee M, Peterson BR. Quantification of Small Molecule-Protein Interactions using FRET between Tryptophan and the Pacific Blue Fluorophore. ACS OMEGA 2016; 1:1266-1276. [PMID: 28058293 PMCID: PMC5204206 DOI: 10.1021/acsomega.6b00356] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/06/2016] [Indexed: 05/14/2023]
Abstract
We report a new method to quantify the affinity of small molecules for proteins. This method is based on Förster resonance energy transfer (FRET) between endogenous tryptophan (Trp) residues and the coumarin-derived fluorophore Pacific Blue (PB). Tryptophan residues are frequently found in proteins near ligand-binding sites, making this approach potentially applicable to a wide range of systems. To improve access to PB, we developed a scalable multigram synthesis of this fluorophore, starting with inexpensive 2,3,4,5-tetrafluorobenzoic acid. This route was used to synthesize fluorescent derivatives of biotin, as well as lower affinity thiobiotin, iminobiotin, and imidazolidinethione analogues that bind the protein streptavidin. Compared with previously published FRET acceptors for tryptophan, PB proved to be superior in both sensitivity and efficiency. These unique properties of PB enabled direct quantification of dissociation constants (Kd) as well as competitive inhibition constants (Ki) in the micromolar to nanomolar range. In comparison to analogous binding studies using fluorescence polarization, fluorescence quenching, or fluorescence enhancement, affinities determined using Trp-FRET were more precise and accurate as validated using independent isothermal titration calorimetry studies. FRET between tryptophan and PB represents a new tool for the characterization of protein-ligand complexes.
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Zhang X, Ba Q, Gu Z, Guo D, Zhou Y, Xu Y, Wang H, Ye D, Liu H. Fluorescent Coumarin-Artemisinin Conjugates as Mitochondria-Targeting Theranostic Probes for Enhanced Anticancer Activities. Chemistry 2015; 21:17415-21. [DOI: 10.1002/chem.201502543] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Indexed: 12/20/2022]
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Dar AA, Chat OA. Cosolubilization of Coumarin30 and Warfarin in Cationic, Anionic, and Nonionic Micelles: A Micelle–Water Interfacial Charge Dependent FRET. J Phys Chem B 2015; 119:11632-42. [DOI: 10.1021/jp511978h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Aijaz Ahmad Dar
- Department of Chemistry, University of Kashmir, Srinagar-190006, Jammu and Kashmir India
| | - Oyais Ahmad Chat
- Department of Chemistry, University of Kashmir, Srinagar-190006, Jammu and Kashmir India
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Maity B, Chatterjee A, Ahmed SA, Seth D. Interaction of the Nonsteroidal Anti-inflammatory Drug Indomethacin with Micelles and Its Release. J Phys Chem B 2015; 119:3776-85. [DOI: 10.1021/acs.jpcb.5b00467] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Banibrata Maity
- Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India
| | - Aninda Chatterjee
- Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India
| | - Sayeed Ashique Ahmed
- Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India
| | - Debabrata Seth
- Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India
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