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At least 109 records · Page 6Linked to original sources
PubMed2000

Porphyrins and related compounds as photoactivatable insecticides. 3. Laboratory and field studies.

The exposure of populations of Ceratitis capitata (fruit fly), Bactrocera oleae (olive fly) and Stomoxis calcitrans (house fly) to a bait containing mumolar concentrations of porphyrin-type photosensitizers resulted in a significant accumulation of the porphyrin by the insects and a consequent development of photosensitivity upon exposure to visible light. The photoinsecticidal activity appeared to increase with increasing hydrophobicity of the porphyrin molecule: thus, the amphiphilic dicationic meso-di(cis-4N-methyl-pyridyl)-cis-diphenyl-porphine (n-octanol/water partition coefficient = 20) was markedly more efficient than its tricationic analogue or the dianionic hematoporphyrin (n-octanol/water partition coefficient = 12). The observed large decrease in the acetylcholinesterase activity of the photosensitized flies suggests that the damage of the nervous system gives an important contribution to the phototoxic action of porphyrins. Studies with C. capitata indicate that the photoinsecticidal action of porphyrins can be utilized to control the population of noxious insects also in open field conditions.

Animals↗
PubMed1998

Porphyrins and related compounds as photoactivatable insecticides. I. Phototoxic activity of hematoporphyrin toward Ceratitis capitata and Bactrocera oleae.

The photodynamic sensitizer hematoporphyrin (HP) IX was efficiently accumulated by Ceratitis capitata (Mediterranean fruit fly) and Bactrocera oleae (olive fly) when the insects were fed with a sugar/protein bait containing micromolar amounts of porphyrin. Hematoporphyrin appeared to be mainly accumulated in the midgut, Malpighian tubes, adipose tissue and cuticle and was gradually cleared from the organism in a 24-48 h time interval. Exposure of the HP-fed flies to light mimicking the solar spectrum caused a decrease in the survival whose extent was modulated by the HP concentration in the bait, the irradiation fluence rate and the total light dose. For 8 mumol/mL HP in the bait 100% mortality during 1 h exposure to light was obtained using a fluence rate of 1220 microE s-1 m-2 for C. capitata and 2080 microE s-1 m-2 for B. oleae. The latter fly was somewhat less photosensitive than C. capitata possibly owing to the smaller amount of ingested HP and/or darker pigmentation. Studies are in progress in order to extend these investigations from the laboratory to the field scale.

Animals↗
PubMedDate not supplied

Inhibition of the mutagenicity of 2-nitrofluorene, 3-nitrofluoranthene and 1-nitropyrene by vitamins, porphyrins and related compounds, and vegetable and fruit juices and solvent extracts.

When 21 vitamins including related compounds haemin, chlorophyllin, chlorophyll, biliverdin and bilirubin, as well as juices from five fruits and 25 vegetables and solvent extracts from the residues of fruits and vegetables were tested for their antimutagenic potencies with respect to mutagenicity induced by 2-nitrofluorene (2-NF), 3-nitrofluoranthene (3-NFA) and 1-nitropyrene(1-NP) in Salmonella typhimurium TA98 the following results were obtained. The tetracyclic nitroarenes 3-NFA and 1-NP were in general more effectively antagonized by potent antimutagenic compounds than the tricyclic 2-NF. beta-Carotene, retinol, retinal, retinoic acid, retinol palmitate, riboflavin 5'-phosphate, alpha-tocopherol, vitamins B12, C, K1 and K3 as well as biliverdin, bilirubin, chlorophyll, chlorophyllin and haemin exerted antimutagenicity against the nitroarenes cited previously. All other vitamins were inactive. While part of the juices were inactive, juices from cauliflower, carrots, chives, radishes and spinach exerted weak antimutagenic activities. However, weak to moderate co-mutagenic effects were seen with grapes, kiwi, pineapple, eggplant, celeriac, chicory greens, fennel leaves and radishes and strong effects with peppers which were not caused by the presence of growth-promoting factors. Most solvent fractions were inactive but fractions containing chlorophyll exerted antimutagenicity.

Antimutagenic Agents↗
PubMed1994

The biomimetic oxidation of beta-1, beta-0-4, beta-5, and biphenyl lignin model compounds by synthetic iron porphyrins.

The degradation of four dimeric lignin model compounds by meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrin iron chloride (TDCSPPFeCl) (2) are reported. 4-Ethoxy-3-methoxyphenylglycerol-beta-guaiacyl ether (3) (a beta-0-4 dimer) was cleaved to give 4-ethoxy-3-methoxybenzaldehyde (4) and guaiacol (5) as major products. The oxidation of 1-(4-ethoxy-3-methoxyphenyl)-2-(4-methoxyphenyl)-1,3-propandiol (6, a beta-1 dimer) gave 4, 4-methoxybenzaldehyde (7), and 4-methoxy-alpha-hydroxyacetophenone (8) as major products. Side chain oxidation and aromatic ring cleavage reactions were found to occur for the phenylcoumaran (alpha-5) model compound, ethyl dehydrodiisoeugenol (12). A biphenyl model compound, 4,4'-diethyldehydrodivanillin (20), was oxidized to give mono- and dicarboxy derivatives, as well as ring-cleaved products of the acid derivatives.

Agaricales↗
PubMed2006

The metal complexes of N-confused porphyrin as heme model compounds.

Recently, metal complexes of the isomers and analogs of porphyrin have become important model compounds for heme enzymes and proteins. While the chemistry of metalloporphyrins as heme models still attracts attention, the isomers and analogs of porphyrins provide insight into the biological choice of porphine as the macrocycle of choice and also help model reactive intermediates, such as high valent oxidation states. In this mini-review, we discuss the heme-relevant chemistry of N-confused porphyrin, an isomer of porphyrin with an inverted pyrrole ring, and focus on the chemistry of manganese, iron, and cobalt. The metallation chemistry of this macrocycle is more diverse than normal porphyrin, and involves tautomerization, C-H bond activation, the Lewis basicity of the external nitrogen, and issues with nucleophilic sensitivity. Despite the challenges posed by N-confused porphyrin, significant progress has been made toward generating heme-model complexes with this macrocycle.

Cobalt↗
PubMed1975

[Studies on the magneto-optical rotation of porphyrins, hemins and methemoglobin compounds].

Using the method of magneto-optical rotation (MOR) various porphyrin derivatives, hemin and heme compounds, and a number of methemoglobin complexes were investigated. The spectra were recorded from 450-600 nm; with methemoglobin also in the Soret region. 1. The metalfree porphyrin derivatives (deutero-, meso-, hemato- and protoporphyrins) were measured in strongly acidic aqueous solution. The derivatives thus present as di-cations yield highly resolved MORspectra, where the Q-bands (Oo leads to; Oo leads to 1) originated from the pi-pi transitions of the porphyrin display the curve shape characteristic of an A-term, this proving the presence of the D4h symmetry. An exception is the protoporphyrin, in which the pi-electron system of the porphyrin is perturbed by the influence of pi-electrons of the vinyl group, causing poor resolution, line broadening, and shift of the Q-bands into the lower-energy spectral region. 2. With iron porphyrins (hemin, heme and their complexes) the charge of the iron and the nature of axial ligands determine the position and intensity of the O-bands in the MOR spectrum. Low-spin complexes have a higher symmetry than the high-spin complexes. Whereas with hemin (S = 5/2), the iron located outside the heme plane strongly disturbs the porphyrin pi-system, the high symmetry of porphyrin is greatly retained in the case of heme. This can be explained by the enhanced binding distance between the bivalent iron and the porphyrin to great for a strong coupling between the microsymmetry of the iron and the macrosymmetry of the porphyrin pi-system.

Heme↗
PubMed1999

[Studies on tailed metalloporphyrin coordination compounds. IX. Synthesis of tailed porphyrin with covalently linked phenylalanine and its fluorescence property].

A new tailed porphyrin with covalently linked phenylalanine 2 and its zinc complex 3 were synthesized. Intramolecular energy transfer (from singlet excited phenylalanine to porphyrin) was observed in compound 2 and 3. The influence of coordination chemistry factor on the fluorescence of porphyrin was also discussed.

Energy Transfer↗
PubMed2001

[Synthesis and electrochemical behavior of new symmetrical porphyrin and cobalt(II) complex].

The synthesis and characterization of mercapto-porphyrin and its cobalt(II) complex are reported. A new method was used to synthesize the porphyrin. These compounds have not been reported previously. Their structural assignment of the porphyrin and its cobalt(II) complex were based on the elemental analysis, UV-Vis, IR and 1H NMR spectra. The elemental analysis data for C44H30N4H4 was C, 69.32(69, 44) H, 4.30(4.24) N, 7.35(7.36). The data of UV-Vis spectra indicated that soret and Q bands of the TMTBP displayed a red-shift in comparison with TPP. The IR spectra of TMTBP showed that the peak of delta (N-H) disappeared, when the cobalt(II) complex was formed. The 1H NMR spectra proved that a new mercapto-porphyrin has been synthesized. This paper also reported electrochemical behavior of new compounds in DMSO by cyclic voltammetry and differential pulse voltammetry.

Chemical Phenomena↗