Chemical modification of chlorophyll a: synthesis of new regiochemically pure benzoporphyrin and dibenzoporphyrin derivatives

1997 ◽  
Vol 75 (3) ◽  
pp. 262-275 ◽  
Author(s):  
Lifu Ma ◽  
David Dolphin
Keyword(s):  
Photodynamic Therapy ◽  
Methyl Ester ◽  
Chemical Modification ◽  
Chlorophyll A ◽  
Degradation Product ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Pheophorbide A ◽  
Potential Use

Starting from pheophorbide a methyl ester (5), a degradation product of chlorophyll a, routes for the preparation of 3-vinylporphyrins 6 and 9 and of an [A,C]-divinylporphyrin 16 are described. These porphyrins were obtained as a result of chemical modification of 5 on ring D and the exocyclic ring E. Diels–Alder reactions of these (di)vinylporphyrins with dimethyl acetylenedicarboxylate, to afford new regiochemically pure benzoporphyrin derivatives 29 and 30 and dibenzoporphyrin derivative 33 for potential use as sensitizers in photodynamic therapy of tumors, were also investigated. Keywords: Diels–Alder, (di)vinylporphyrins, (di)benzoporphyrins, photodynamic therapy, chlorophyll.

scholarly journals Transformation Chlorophyll a of Spirulina platensis to Chlorin e6 Derivatives and Several Applications

2019 ◽  
Vol 7 (24) ◽  
pp. 4372-4377
Author(s):  
Hoa Thi Hai Bui ◽  
Tam Thi Pham ◽  
Hien Thi Thu Nguyen ◽  
Trung Minh Do ◽  
Vu Thi Nga ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Chlorophyll A ◽  
Hela Cells ◽  
Spirulina Platensis ◽  
Antimicrobial Effect ◽  
Chlorin E6 ◽  
Viet Nam ◽  
Pheophorbide A ◽  
Halogen Light ◽  
And Staphylococcus Aureus

BACKGROUND: Spirulina platensis contains a large amount of chlorophylls, chlorophyll a, that are starting materials to synthesize functionalized chlorins. Chlorin e6 (Ce6) as well as its derivatives are second generation sensitizers using in photodynamic therapy (PDT) of various cancers. In this study, we transfer chlorophyll a of S. platensis to Ce6derivatives and determine their several applications. AIM: to evaluate the effects of Ce6 derivatives to treat cancer cells. METHODS: Ce6 trimethylester was created from methyl pheophorbide a2 in S. platensis provided by the Hidumi Company, Nghe An province, Viet Nam. Hela cells were incubated with Ce6 trimethylester and the irradiated with the diode laser dose of 1.2 J/cm2/min through the system of filters £ 650 nm. MTT assay and clonogenic assay were used to determine survival rate and cloning efficiency of cells. Antimicrobial effect of Ce6 trimethylester with halogen light were studied with Propionibacterium acnes VTCC 0218 and Staphylococcus aureus VTCC 0173. RESULTS: From dry biomass (700 g) of S. platensis, after extracting chlorophyll a and methanolysis, 4.2 g of methyl pheophorbide a was obtained. The reaction to give Ce6 trimethylester with 82% yield was performed with potassium hydroxide (KOH) in MeOH/THF/CHCl3. After irradiation with a 650 nm laser at 1.2 J, the cell viability in all samples decreased with Ce6 trimethylester treatment, the survival declining trend of Hela cells treated with Ce6 trimethylester were proportional when concentration of Ce6 trimethylester increased. The rate of colony formation was declined as the concentration of Ce6 trimethylester treated was increased. The growth of both S. aureus and P. acnes can be inactivated by Ce6 trimethylester PDT. The MIC99 value against P. acnes VTCC 0218 and S. aureus VTCC 0173 of Ce6 trimethylester with halogen light was 1.25 μg/ml. CONCLUSION: The Ce6 trimethylester from S. platensis cultivated in Viet Nam could be used as a potential photosentizer for photodynamic therapy for treatment of cancer and acne.

scholarly journals Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1409
Author(s):  
Hamdhani Hamdhani ◽  
Drew E. Eppehimer ◽  
David Walker ◽  
Michael T. Bogan
Keyword(s):  
Chlorophyll A ◽  
Surface Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Water Quality Monitoring ◽  
Ambient Light ◽  
Calibration Equation ◽  
Field Samples ◽  
Potential Use

Chlorophyll-a measurements are an important factor in the water quality monitoring of surface waters, especially for determining the trophic status and ecosystem management. However, a collection of field samples for extractive analysis in a laboratory may not fully represent the field conditions. Handheld fluorometers that can measure chlorophyll-a in situ are available, but their performance in waters with a variety of potential light-interfering substances has not yet been tested. We tested a handheld fluorometer for sensitivity to ambient light and turbidity and compared these findings with EPA Method 445.0 using water samples obtained from two urban lakes in Tucson, Arizona, USA. Our results suggested that the probe was not sensitive to ambient light and performed well at low chlorophyll-a concentrations (<25 µg/L) across a range of turbidity levels (50–70 NTU). However, the performance was lower when the chlorophyll-a concentrations were >25 µg/L and turbidity levels were <50 NTU. To account for this discrepancy, we developed a calibration equation to use for this handheld fluorometer when field monitoring for potential harmful algal blooms in water bodies.

Optimized Combination of Photodynamic Therapy and Chemotherapy Using Gelatin Nanoparticles Containing Tirapazamine and Pheophorbide a

2021 ◽  
Vol 13 (9) ◽  
pp. 10812-10821
Author(s):  
Donghyun Lee ◽  
Seok-young Jang ◽  
Soonmin Kwon ◽  
Yeeun Lee ◽  
Eunyoung Park ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Pheophorbide A ◽  
Gelatin Nanoparticles

scholarly journals Pheophorbide a: State of the Art

Marine Drugs ◽  
2020 ◽  
Vol 18 (5) ◽  
pp. 257 ◽  
Author(s):  
Assunta Saide ◽  
Chiara Lauritano ◽  
Adrianna Ianora
Keyword(s):  
Clinical Trials ◽  
Photodynamic Therapy ◽  
Anticancer Activity ◽  
State Of The Art ◽  
Human Cancer ◽  
Human Cancer Cell ◽  
Pheophorbide A ◽  
Human Cancer Cell Lines ◽  
Chlorophyll Breakdown ◽  
Chlorophyll Derivative

Chlorophyll breakdown products are usually studied for their antioxidant and anti-inflammatory activities. The chlorophyll derivative Pheophorbide a (PPBa) is a photosensitizer that can induce significant anti-proliferative effects in several human cancer cell lines. Cancer is a leading cause of death worldwide, accounting for about 9.6 million deaths, in 2018 alone. Hence, it is crucial to monitor emergent compounds that show significant anticancer activity and advance them into clinical trials. In this review, we analyze the anticancer activity of PPBa with or without photodynamic therapy and also conjugated with or without other chemotherapic drugs, highlighting the capacity of PPBa to overcome multidrug resistance. We also report other activities of PPBa and different pathways that it can activate, showing its possible applications for the treatment of human pathologies.

Diels-Alder reaction of pyrrole with dimethyl acetylenedicarboxylate

1978 ◽  
Vol 43 (19) ◽  
pp. 3727-3729 ◽  
Author(s):  
Chang Kiu Lee ◽  
Chi Sun Hahn ◽  
Wayland E. Noland
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Diels Alder Reaction

scholarly journals Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

scholarly journals Two-Photon–NIR-II Antimicrobial Graphene-Nanoagent for Ultraviolet–NIR Imaging and Photoinactivation

2021 ◽  
Author(s):  
WEN-SHUO KUO ◽  
Chia-Yuan Chang ◽  
Ping-Ching Wu ◽  
Jiu-Yao Wang
Keyword(s):  
Photodynamic Therapy ◽  
Quantum Yield ◽  
Chemical Modification ◽  
Near Infrared ◽  
Photon Absorption ◽  
Excitation Wavelength ◽  
Strong Electron ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Excitation

Abstract BackgroundNitrogen doping and amino-group functionalization, which result in strong electron donation, can be achieved through chemical modification. Large π-conjugated systems of graphene quantum dot (GQD)-based materials acting as electron donors can be chemically manipulated with low two-photon excitation energy in a short photoexcitation time for improving the charge transfer efficiency of sorted nitrogen-doped amino acid–functionalized GQDs (sorted amino-N-GQDs). ResultsIn this study, a self-developed femtosecond Ti-sapphire laser optical system (222.7 nJ pixel−1 with 100-170 scans, approximately 0.65-1.11 s of total effective exposure times; excitation wavelength: 960 nm in the near-infrared II region) was used for chemical modification. The sorted amino-N-GQDs exhibited enhanced two-photon absorption, post-two-photon excitation stability, two-photon excitation cross-section, and two-photon luminescence through the radiative pathway. The lifetime and quantum yield of the sorted amino-N-GQDs decreased and increased, respectively. Furthermore, the sorted amino-N-GQDs exhibited excitation-wavelength-independent photoluminescence in the near-infrared region and generated reactive oxygen species after two-photon excitation. An increase in the size of the sorted amino-N-GQDs boosted photochemical and electrochemical efficacy and resulted in high photoluminescence quantum yield and highly efficient two-photon photodynamic therapy. ConclusionThe sorted dots can be used in two-photon contrast probes for tracking and localizing analytes during two-photon imaging in a biological environment and for conducting two-photon photodynamic therapy for eliminating infectious microbes.

scholarly journals Applications of Oxygen-Carrying Micro/Nanobubbles: a Potential Approach to Enhance Photodynamic Therapy and Photoacoustic Imaging

2018 ◽  
Author(s):  
M. Saad Khan ◽  
Jangsun Hwang ◽  
Kyungwoo Lee ◽  
Yonghyun Choi ◽  
Kyobum Kim ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Oxygen Supply ◽  
Photoacoustic Imaging ◽  
Supply And Demand ◽  
Flexible Structures ◽  
Synthesis Methods ◽  
Oxygen Species ◽  
Hypoxic Conditions ◽  
Potential Use ◽  
Resistance To Chemotherapy

Microbubbles and nanobubbles can be prepared using various shells, such as phospholipids, polymers, proteins, and surfactants. They are echogenic and can be used as contrast agents for ultrasonic and photoacoustic imaging. These bubbles can be engineered in various sizes as vehicles for gas and drug delivery applications with novel properties and flexible structures. Hypoxic areas in tumors develop owing to an imbalance of oxygen supply and demand. In tumors, hypoxic regions have shown more resistance to chemotherapy, radiotherapy, and photodynamic therapies. The efficacy of photodynamic therapy depends on the availability of oxygen in the tumor to generate reactive oxygen species. Micro/nanobubbles have been shown to reverse hypoxic conditions and increase tissue oxygen levels. This review summarizes the synthesis methods and shell compositions of micro/nanobubbles and methods deployed for oxygen delivery. In addition, the shortcomings and prospects of engineering micro/nanobubbles are discussed for their potential use in photodynamic therapy.

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