Chlorophyll derivative

In a study of the photoreduction of zinc(II) or magnesium chlorophyll derivatives 8 with ascorbic acid in the presence of l,4-diazabicyclo[2.2.2]octane (DABC-O), a 2,3-m-hydrogenated isobacteriochlorin 9 is formed which subsequently rearranges to a 3-ethylidenc derivative... 

Several chlorophyll derivatives have been prepared by electrophilic substitution, inter alia by formylation reactions. Adopting methods from corrin chemistry.50 alkylation with chloro-methyl methyl ether (caution toxic),32k chloromethyl methyl sulfide,51 and dichloromethyl methyl ether (caution toxic)52 in the presence of Lewis acids are the methods of choice to introduce carbon residues into the chlorin frame work. The compounds listed below have been prepared by these methods. 

The formation of bacteriochlorins from chlorophyll derivatives has also been studied.8 The reduction product 16 of methyl 3 -oxorhodochlorin-l 5-acetate (see Section 1.2.2.) undergoes photooxygenation with singlet oxygen to yield finally a bacteriochlorin 17. 

Transformations which alter the bacteriochlorin chromophore are quite rare. An important reaction in the structural elucidation of the bacteriochlorophylls is the dehydrogenation to chlorophyll derivatives. Thus, bacteriopyromethylpheophorbide a (1) can be smoothly dehydrogenated with 3,4,5,6-tetrachloro-l,2-benzoquinone to the corresponding chlorin 3-acetyl-pyromethylpheophorbide a (2) in high yield.1 la,b... 

Nickel(II) chlorophyll derivatives undergo catalytic hydrogenation with Raney nickel as catalyst to yield stereoisomeric isobacteriochlorins in which ring A of the chlorophyll derivatives is reduced.16... 

Shimomura, O. (1980). Chlorophyll-derived bile pigment in bioluminescent euphausiids. FEBS Lett. 116 203-206. 

There is also evidence that individual chlorophyll derivatives exhibit cytostatic and cytotoxic activities against tumor cells. Studies have been started on electronic structures, in particular the electronic state of the phorphyrin macrocycle, and progress in this area is expected regarding photodynamic therapy for tumors, since the strong absorption of hght in the visible region is effective for laser excitation. Nevertheless, httle is known to date about the influences of peripheral groups on the electronic state of the macrocycle n system in chlorophyll derivatives. ... 

Chernomorsky, S., Segehnan, A., and Poretz, R.D., Effect of dietary chlorophyll derivatives on mutagenesis and tumor cell growth, Teratog. Carcinog. Mutag, 19, 313, 1999. 

Ferruzzi, M.G. and Blakeslee, J., Digestion, absorption and cancer preventative activity of dietary chlorophyll derivatives, Nutr. Res., 21, 1, 2007. 

Ferruzzi, M.G. et al.. Antioxidant and antimutagenic activity of dietary chlorophyll derivatives determined by radical scavenging and bacterial reverse mutagenesis assays, J. Food ScL, 67, 2589, 2002. 

Schluter, A. et al.. The chlorophyll-derived metabolite phytanic acid induces white adipocyte differentiation, Int. J. Obes., 26, 1277, 2002. 

Ferruzzi, M.G., Failla, M.L., and Schwartz, S.J., Assessment of degradation and intestinal cell uptake of carotenoids and chlorophyll derivatives from spinach puree using an in vitro digestion and Caco-2 cell model, J. Agric. Food Chem., 49, 2082, 2001. 

The aim of this chapter is to provide a concise synopsis of the factors that promote degradation during post-harvest handling, processing, and storage, and the strategies to preserve the green color of the most commonly consumed chlorophyU-rich foods. Some considerations about the production and characteristics of natural and semisynthetic chlorophyll derivatives for use as food colorants are also presented. 

LaBorde, L.R and Von Elbe, J.H, Chlorophyll degradation and zinc complex formation with chlorophyll derivatives in heated green vegetables, J. Agric. Food Chem., 42, 1100, 1994. 

Kephart, J.C., Chlorophyll derivatives their chemistry, commercial preparation and uses, Econ. Bot., 9, 3, 1955. 

A normal-phase HPLC separation seems to be useful to separate major chlorophyll derivatives, but it is not compatible with samples in water-containing solvents an additional extraction step is required to eliminate water from the extract since its presence rednces chromatographic resolution and interferes with retention times. Besides that, the analysis cannot be considered quantitative due to the difhculty in transferring componnds from the acetone solution into the ether phase. On the other hand, an advantage of the normal-phase method is its efficacy to separate magne-sinm-chlorophyll chelates from other metal-chelated chlorophyll derivatives. ... 

The development and reports of methods for colorless chlorophyll derivative (RCCs, FCCs, and NCCs) analysis are relatively recent and the structures of the compounds are being elucidated by deduction from their chromatographic behaviors, spectral characteristics (UV-Vis absorbance spectra), mass spectrometry, and nuclear magnetic resonance analysis. The main obstacle is that these compounds do not accumulate in appreciable quantities in situ and, moreover, there are no standards for them. The determination of the enzymatic activities of red chlorophyll catabolite reductase (RCCR) and pheophorbide a monoxygenase (PAO) also helps to monitor the appearance of colorless derivatives since they are the key enzymes responsible for the loss of green color. ... 

Evans, N. et al.. Applications of high-pressure liquid chromatogrphy and field desorption mass spectrometry in studies of natural porphyrins and chlorophyll derivatives, J. Ghromatogr, 115, 325, 1975. 

Hendry, G.A.F., Chlorophylls and chlorophyll derivatives, in Natural Food Colorants, 2nd Ed., Hendry, G.A.F. and J.D. Houghton, Eds., Blackie, Glasgow, 1996, 131. Singh, V., ed., Seabuckthom, A Multipurpose Wonder Plant, Vol. I, Indus International, India, 2005. 

Chapter 13 is devoted to the PLC of namral pigments, which encompass fla-vonoids, anthocyanins, carotenoids, chlorophylls and chlorophyll derivatives, porphyrins, quinones, and betalains. Chromatography of pigments is especially difficult because many are photo- and air-sensitive and can degrade rapidly unless precautions are taken. 

Proponents of each of these mechanisms attack the other with numerous criticisms. Those favoring the mole-oxide intermediate (mechanism A) claim that (1) the singlet oxygen mechanism does not adequately describe the observed kinetics(87) and (2), it is eliminated since a chlorophyll derivative with a triplet energy too low to excite oxygen to its singlet level is still effective in producing product by the steps<90>... 

O Neil, C. A. and S. J. Schwartz. 1995. Photoisomerization of 3-carotene by photosensitization with chlorophyll derivatives as sensitizers. J. Agric. Food Chem. 43 631-635. 

Zurer, P. "Dragon Fish Uses Chlorophyll Derivatives to See in the Dark."... 

Fig. 2.130. Elution profile by RP-HPLC of the chlorophyll derivative pigments analysed. The pigments were detected spectrophotometrically at 660 nm and fhiorimetrically using excitation and emission wavelengths at 440 and 660 nm, respectively. Peak identification (numbers in parentheses are retention times in min) 1 = chlorophyllide-b (3.10) 2 = chlorophyllide-a (4.98) 3 = pheophorbide-b (7.44) 4 = pheophorbide-a (8.85) 5 = chlorophyll-b (14.74) 6 = chlorophyll-a (16.40) 7 = pheophytin-b (21.49) 8 = pheophytin-a (23.38). Reprinted with permission from L. Almela et al. [301].

L. Almela, J.A. Femandez-Lopez and M.J. Roca, High-performance liquid chromatographic screening of chlorophyll derivatives produced during fruit storage. J. Chromatogr.A 870 (2000) 483 189. 

J. W. Jonker, M. Buitelaar, E. Wagenaar, M. A. Van Der Valk, G. L. Scheffer, R. J. Scheper, T. Plosch, F. Kuipers, R. P. Elferink, H. Rosing, J. H. Beijnen, and A. H. Schinkel. The breast cancer resistance protein protects against a major chlorophyll-derived dietary phototoxin and protoporphyria. Proc Natl Acad Sci U S A 99 15649-15654 (2002). 

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