Hemisynthesis of 132,173-cyclomesopheophorbide-a-enol

Khalesi, Mitra; Louda, J. William

doi:10.1016/j.tetlet.2010.12.079

Cited by 4 publications

(2 citation statements)

References 19 publications

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“…Previous studies have frequently regarded cPPB-aE as an antioxidant that accumulates in marine macrofauna (11,(13)(14)(15)(16). However, other workers have failed to highlight the possibility that the primary evolutionary advantage of cPPB-aE production by single-celled organisms is the detoxification of the phototoxic chlorophyll derivatives that are inevitably ingested on feeding chlorophyll-containing diets to protists in an illuminated and aerated environment.…”

Section: Resultsmentioning

confidence: 99%

“…We developed improved analytical methods that enable quantitative identification of unstable cPPB-aE from microbiological and environmental samples with high sensitivity. Analytical difficulties arose as a consequence of the instability of cPPB-aE during handling during extraction and analysis involving HPLC (11,13,17). Given that cPPBaE is rather unstable in most organic solvents in the presence of molecular oxygen, it was rapidly degraded, especially when present at low concentrations.…”

Section: Methodsmentioning

confidence: 99%

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Ubiquity and quantitative significance of detoxification catabolism of chlorophyll associated with protistan herbivory

Kashiyama

Yokoyama²,

Kinoshita

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Chlorophylls are essential components of the photosynthetic apparati that sustain all of the life forms that ultimately depend on solar energy. However, a drawback of the extraordinary photosensitizing efficiency of certain chlorophyll species is their ability to generate harmful singlet oxygen. Recent studies have clarified the catabolic processes involved in the detoxification of chlorophylls in land plants, but little is understood about these strategies in aquatic ecosystem. Here, we report that a variety of heterotrophic protists accumulate the chlorophyll a catabolite 13 2 ,17 3 -cyclopheophorbide a enol (cPPB-aE) after their ingestion of algae. This chlorophyll derivative is nonfluorescent in solution, and its inability to generate singlet oxygen in vitro qualifies it as a detoxified catabolite of chlorophyll a. Using a modified analytical method, we show that cPPBaE is ubiquitous in aquatic environments, and it is often the major chlorophyll a derivative. Our findings suggest that cPPB-aE metabolism is one of the most important, widely distributed processes in aquatic ecosystems. Therefore, the herbivorous protists that convert chlorophyll a to cPPB-aE are suggested to play more significant roles in the modern oceanic carbon flux than was previously recognized, critically linking microscopic primary producers to the macroscopic food web and carbon sequestration in the ocean. phototoxicity of chlorophylls | microbial herbivory | phagocytosis | biodiversity of eukaryotes | microbial loop C hlorophylls are crucial to sustaining most life forms on Earth, the majority of which ultimately depend on solar energy. Photoexcitation of chlorophylls initiates various photosynthetic reactions that convert the energy of photons into chemical potentials, which in turn, drive the full range of metabolic reactions throughout the global ecosystem. Chlorophylls play a central role in the photosynthetic apparatus by absorbing light and transferring the excitation energy to the reaction centers of photosystems before photosynthetic electron transport. However, without measures to contain the excited energy, chlorophylls can harm organisms because of their high photosensitizing potential.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Ubiquity and quantitative significance of detoxification catabolism of chlorophyll associated with protistan herbivory

Kashiyama

Yokoyama²,

Kinoshita

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Synthesis of 132,173-cyclopheophorbides and their optical properties

Kinoshita

Demise

Ishikawa

et al. 2021

Journal of Photochemistry and Photobiology A: Chemistry

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Extra-Annulated Chlorophyll Derivatives by Scholl Reaction

Imuta,

Hara,

Ogasawara

et al. 2024

Org. Lett.

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The ferric chloride assisted Scholl reaction of methyl (3,5-dimethoxyphenyl)carbonyl-pyropheophorbide-a produced an extra-annulated, didehydrogenated chlorophyll derivative with a six-membered ring fused at the pyrrole A-ring. The steric interaction of the substituents on the additional tetralone and Brings induced molecular helicity. The helically cyclized stereoisomers were separated by recrystallization, and their (P/M)stereochemistry was confirmed by circular dichroism spectra. The distortion of their chlorin π-systems broadened electronic absorption bands to cover all visible regions and reach the nearinfrared region.Letter pubs.acs.org/OrgLett

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Hemisynthesis of 132,173-cyclomesopheophorbide-a-enol

Cited by 4 publications

References 19 publications

Ubiquity and quantitative significance of detoxification catabolism of chlorophyll associated with protistan herbivory

Ubiquity and quantitative significance of detoxification catabolism of chlorophyll associated with protistan herbivory

Synthesis of 132,173-cyclopheophorbides and their optical properties

Extra-Annulated Chlorophyll Derivatives by Scholl Reaction

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