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Mini Reviews in Medicinal Chemistry 2017Thylakoids and chloroplasts harbor several vital metabolic processes, but are most importantly associated with photosynthesis. The undisturbed functioning of this... (Review)
Review
BACKGROUND & OBJECTIVE
Thylakoids and chloroplasts harbor several vital metabolic processes, but are most importantly associated with photosynthesis. The undisturbed functioning of this process necessitates the ceaseless synthesis of photosynthetic pigments, including closed tetrapyrroles such as chlorophylls (Chls). Chls probably represent the most abundant natural pigment molecules which are via photosynthesis not only crucial for the autotrophic production of food sources for heterotrophic organisms but have also contributed to oxygen production essential for aerobic metabolism. This review first briefly discusses the physico-chemical properties, biosynthesis, occurrence, in vivo localization and roles of the different Chl pigments. Then we provide a detailed overview of their potential applications in the food industry and medicine. These include the use of Chls and their derivatives (different chlorophyllins) as food colorants (identified as E140 and E141 in the European Union).
METHOD
Different sources used for industrial extraction as well as different factors influencing pigment stability during processing are also critically reviewed. The problems surrounding the nomenclature, the production and the composition of different chlorophyllin mixtures are also discussed.
RESULTS & CONCLUSION
Finally, a comprehensive overview of the health benefits and potential medicinal applications of these pigments and the future directions of research in these fields are provided.
Topics: Antineoplastic Agents; Antioxidants; Chlorophyll; Chlorophyllides; Food Coloring Agents; Humans; Neoplasms; Photochemotherapy
PubMed: 27719668
DOI: 10.2174/1389557516666161004161411 -
Molecules (Basel, Switzerland) Jan 2019Although there is no legal and clear definition of the term "natural food colorant", the market trends, and consequently industrial and commercial interest, have turned... (Review)
Review
Although there is no legal and clear definition of the term "natural food colorant", the market trends, and consequently industrial and commercial interest, have turned to foods with added natural pigments. This progressive substitution of artificial colorants has faced chemical complications with some colors, with a lack of stable green hues being one of them. Several strategies have been applied for green color stabilization in processed foods, from the formation of metallochlorophylls to the microencapsulation of green pigments. However, at present, the utilization of green coloring foodstuffs, which are considered an ingredient in the EU, seems to be the more successful solution for the market. Besides those topics, the present review aims to clarify the current confusion between the different chlorophyll compounds that form part of the authorized green food colorants. In this sense, legislations from different countries are compared. Finally, and in line with current concerns, the knowledge gathered so far in relation to the absorption, distribution, metabolism and excretion of all green natural food colorants is reviewed.
Topics: Biological Products; Chlorophyll; Color; Complex Mixtures; Coordination Complexes; Food Coloring Agents; Green Chemistry Technology; Molecular Structure; Pigments, Biological; Solid Phase Extraction; Structure-Activity Relationship
PubMed: 30609768
DOI: 10.3390/molecules24010154 -
Molecules (Basel, Switzerland) Feb 2022Chlorophylls provide the basis for photosynthesis and thereby most life on Earth. Besides their involvement in primary charge separation in the reaction center, they...
Chlorophylls provide the basis for photosynthesis and thereby most life on Earth. Besides their involvement in primary charge separation in the reaction center, they serve as light-harvesting and light-sensing pigments, they also have additional functions, e.g., in inter-system electron transfer. Chlorophylls also have a wealth of applications in basic science, medicine, as colorants and, possibly, in optoelectronics. Considering that there has been more than 200 years of chlorophyll research, one would think that all has been said on these pigments. However, the opposite is true: ongoing research evidenced in this Special Issue brings together current work on chlorophylls and on their carotenoid counterparts. These introductory notes give a very brief and in part personal account of the history of chlorophyll research and applications, before concluding with a snapshot of this year's publications.
Topics: Carotenoids; Chlorophyll; Electron Transport; Energy Transfer; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Light-Harvesting Protein Complexes; Photosynthesis
PubMed: 35164358
DOI: 10.3390/molecules27031093 -
Methods in Molecular Biology (Clifton,... 2018The most obvious event of leaf senescence is the loss of chlorophyll. Chlorophyll degradation proceeds in a well-characterized pathway that, although being common to...
The most obvious event of leaf senescence is the loss of chlorophyll. Chlorophyll degradation proceeds in a well-characterized pathway that, although being common to higher plants, yields a species-specific set of chlorophyll catabolites, termed phyllobilins. Analysis of chlorophyll degradation and phyllobilin accumulation by high-performance liquid chromatography (HPLC) is a valuable tool to investigate senescence processes in plants. In this chapter, methods for the extraction, separation, and quantification of chlorophyll and its degradation products are described. Because of their different physicochemical properties, chlorin-type pigments (chlorophylls and magnesium-free pheo-pigments) and phyllobilins (linear tetrapyrroles) are analyzed separately. Specific spectral properties and polarity differences allow the identification of the different classes of known chlorins and phyllobilins. The methods provided facilitate the analysis of chlorophyll degradation and the identification of chlorophyll catabolites in a wide range of plant species, in different tissues, and under a variety of physiological conditions that involve loss of chlorophyll.
Topics: Aging; Biomarkers; Chlorophyll; Chromatography, High Pressure Liquid; Molecular Structure; Plant Leaves; Plants
PubMed: 29392669
DOI: 10.1007/978-1-4939-7672-0_18 -
Biomolecules Jul 2021Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have -, -, -, -, and -type derivatives, and all chlorophyllides have a tetrapyrrole... (Review)
Review
Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have -, -, -, -, and -type derivatives, and all chlorophyllides have a tetrapyrrole structure with a Mg ion at the center and a fifth isocyclic pentanone. Chlorophyllide can be synthesized from protochlorophyllide , divinyl chlorophyllide , or chlorophyll. In addition, chlorophyllide can be transformed into chlorophyllide , chlorophyllide , or chlorophyllide . Chlorophyllide can be synthesized from protochlorophyllide or divinyl protochlorophyllide . Chlorophyllides have been extensively used in food, medicine, and pharmaceutical applications. Furthermore, chlorophyllides exhibit many biological activities, such as anti-growth, antimicrobial, antiviral, antipathogenic, and antiproliferative activity. The photosensitivity of chlorophyllides that is applied in mercury electrodes and sensors were discussed. This article is the first detailed review dedicated specifically to chlorophyllides. Thus, this review aims to describe the definition of chlorophyllides, biosynthetic routes of chlorophyllides, purification of chlorophyllides, and applications of chlorophyllides.
Topics: Anti-Infective Agents; Antineoplastic Agents, Phytogenic; Antiviral Agents; Biosensing Techniques; Chemistry, Pharmaceutical; Chlorophyll; Chlorophyllides; Electrochemical Techniques; Food Additives; Humans; Light; Molecular Structure; Photosynthesis; Plants; Protochlorophyllide
PubMed: 34439782
DOI: 10.3390/biom11081115 -
Marine Drugs May 2020Chlorophyll breakdown products are usually studied for their antioxidant and anti-inflammatory activities. The chlorophyll derivative Pheophorbide (PPB) is a... (Review)
Review
Chlorophyll breakdown products are usually studied for their antioxidant and anti-inflammatory activities. The chlorophyll derivative Pheophorbide (PPB) 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 PPB with or without photodynamic therapy and also conjugated with or without other chemotherapic drugs, highlighting the capacity of PPB to overcome multidrug resistance We also report other activities of PPB and different pathways that it can activate, showing its possible applications for the treatment of human pathologies.
Topics: Antineoplastic Agents; Cell Line, Tumor; Chlorophyll; Humans
PubMed: 32423035
DOI: 10.3390/md18050257 -
Lab on a Chip Jun 2016Chlorophylls are essential for photosynthesis and also one of the most abundant pigments on earth. Using an optofluidic ring resonator of extremely high Q-factors...
Chlorophylls are essential for photosynthesis and also one of the most abundant pigments on earth. Using an optofluidic ring resonator of extremely high Q-factors (>10(7)), we investigated the unique characteristics and underlying mechanism of chlorophyll lasers. Chlorophyll lasers with dual lasing bands at 680 nm and 730 nm were observed for the first time in isolated chlorophyll a (Chla). Particularly, a laser at the 730 nm band was realized in 0.1 mM Chla with a lasing threshold of only 8 μJ mm(-2). Additionally, we observed lasing competition between the two lasing bands. The presence of laser emission at the 680 nm band can lead to quenching or significant reduction of laser emission at the 730 nm band, effectively increasing the lasing threshold for the 730 nm band. Further concentration-dependent studies, along with theoretical analysis, elucidated the mechanism that determines when and why the laser emission band appears at one of the two bands, or concomitantly at both bands. Finally, Chla was exploited as the donor in fluorescence resonance energy transfer to extend the laser emission to the near infrared regime with an unprecedented wavelength shift as large as 380 nm. Our work will open a door to the development of novel biocompatible and biodegradable chlorophyll-based lasers for various applications such as miniaturized tunable coherent light sources and in vitro/in vivo biosensing. It will also provide important insight into the chlorophyll fluorescence and photosynthesis processes inside plants.
Topics: Chlorophyll; Equipment Design; Fluorescence Resonance Energy Transfer; Lasers; Microfluidics; Optics and Photonics
PubMed: 27220992
DOI: 10.1039/c6lc00512h -
Biochimica Et Biophysica Acta Aug 2011Chlorophyll breakdown is an important catabolic process of leaf senescence and fruit ripening. Structure elucidation of colorless linear tetrapyrroles as (final)... (Review)
Review
Chlorophyll breakdown is an important catabolic process of leaf senescence and fruit ripening. Structure elucidation of colorless linear tetrapyrroles as (final) breakdown products of chlorophyll was crucial for the recent delineation of a chlorophyll breakdown pathway which is highly conserved in land plants. Pheophorbide a oxygenase is the key enzyme responsible for opening of the chlorin macrocycle of pheophorbide a characteristic to all further breakdown products. Degradation of chlorophyll was rationalized by the need of a senescing cell to detoxify the potentially phototoxic pigment, yet recent investigations in leaves and fruits indicate that chlorophyll catabolites could have physiological roles. This review updates structural information of chlorophyll catabolites and the biochemical reactions involved in their formation, and discusses the significance of chlorophyll breakdown. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
Topics: Chlorophyll; Chlorophyll A; Oxygenases; Plants
PubMed: 21167811
DOI: 10.1016/j.bbabio.2010.12.007 -
Cells Nov 2021Chlorophylls (Chls, Chl and Chl ) are tetrapyrrole molecules essential for photosynthetic light harvesting and energy transduction in plants. Once formed, Chls are... (Review)
Review
Chlorophylls (Chls, Chl and Chl ) are tetrapyrrole molecules essential for photosynthetic light harvesting and energy transduction in plants. Once formed, Chls are noncovalently bound to photosynthetic proteins on the thylakoid membrane. In contrast, they are dismantled from photosystems in response to environmental changes or developmental processes; thus, they undergo interconversion, turnover, and degradation. In the last twenty years, fruitful research progress has been achieved on these Chl metabolic processes. The discovery of new metabolic pathways has been accompanied by the identification of enzymes associated with biochemical steps. This article reviews recent progress in the analysis of the Chl cycle, turnover and degradation pathways and the involved enzymes. In addition, open questions regarding these pathways that require further investigation are also suggested.
Topics: Chlorophyll; Enzymes; Models, Biological; Plants; Research
PubMed: 34831365
DOI: 10.3390/cells10113134 -
Photosynthesis Research Apr 2023An electron-vibrational coupling model that includes the vibronic (non-adiabatic) coupling between the Q[Formula: see text] and Q[Formula: see text] transitions of...
An electron-vibrational coupling model that includes the vibronic (non-adiabatic) coupling between the Q[Formula: see text] and Q[Formula: see text] transitions of chlorophyll (Chl), created by Reimers and coworkers (Scientific Rep. 3, 2761, 2013) is extended here to chlorophyll dimers with interchlorophyll excitonic coupling. The model is applied to a Chl a dimer of the water-soluble chlorophyll binding protein (WSCP). As for isolated chlorophyll, the vibronic coupling is found to have a strong influence on the high-frequency vibrational sideband in the absorption spectrum, giving rise to a band splitting. In contrast, in the CD spectrum the interplay of vibronic coupling and static disorder leads to a strong suppression of the vibrational sideband in excellent agreement with the experimental data. The conservative nature of the CD spectrum in the low-energy region is found to be caused by a delicate balance of the intermonomer excitonic coupling between the purely electronic Q[Formula: see text] transition and the Q[Formula: see text] transition involving intramolecular vibrational excitations on one hand and the coupling to higher-energy electronic transitions on the other hand.
Topics: Chlorophyll; Chlorophyll A
PubMed: 36040654
DOI: 10.1007/s11120-022-00946-3