chlorophyll-a and methylpheophorbide

Zinc 3-hydroxymethyl-13

Topics: Alkylation; Bacterial Proteins; Bacteriochlorophylls; Chlorophyll; Circular Dichroism; Isomerism; Micelles; Models, Molecular; Porphyrins; Solutions; Water; Zinc

An amphiphilic chlorin derivative (CHL-T) was prepared from methylpheophorbide a (CHL) and 2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRISMA

Topics: Anthracenes; Cell Death; Chlorophyll; HeLa Cells; Humans; Microscopy, Fluorescence; Perylene; Photochemotherapy; Photosensitizing Agents

Methylphophorbide a (MPa) has been isolated from the ethanol extract of the wheat grass plant. Its antioxidative efficacy is evaluated by hydroxyl radical scavenging activities and reducing capacity which are significantly up regulated in comparison with aqueous extract of the plant. The compound shows iron-binding capacity where the Fe(2+) binds with MPa by two types of binding patterns with dissociation constants 157.17 and 27.89. It has antioxidative and cytotoxic effects on HeLa and Hep G2 cells. The cancerous cell survivability decreases with increasing concentration of MPa. These findings have provided evidence for the traditional use of the wheat grass plant in the treatment of cancers, oxidative stress and iron overloaded disorders.

Topics: Antineoplastic Agents, Phytogenic; Antioxidants; Apoptosis; Chlorophyll; HeLa Cells; Hep G2 Cells; Humans; Oxidative Stress; Plant Extracts; Triticum

Methyl pheophorbide-a/a' derivatives covalently linked with oligomethylene chains at the 3-CH(2)OCO- and 13(2)-COO- moieties in a molecule were prepared by modifying chlorophyll-a through intramolecular ring-closing metathesis of vinyl groups. At least, a C10-length between the 3(3)- and 13(4)-positions was necessary for the cyclization and connection of a C12-strap was the most suitable to achieve the highest closure yield. The oligomethylene chain in 13(2) R-epimers derived from methyl pheophorbide-a covered the α-face of the chlorin π-plane and the strap in the corresponding 13(2) S-epimers protected the β-face. Synthetic 13(2) R-epimer with a dodecamethylene chain gave a flat chlorin π-plane, while the decamethylene chain in the 13(2) R-epimer distorted the π-system due to its shorter linkage. The distortion by strapping in the 13(2) R-epimer induced a slight blue-shift of Qy peak in dichloromethane. CD spectra of the 13(2) R-epimers were similarly dependent on the chain length, i.e., the distortion of π-plane. Visible absorption and CD spectra of all the strapped 13(2) S-epimers were almost identical and only slightly different from those of the unstrapped. The strapping in the 13(2) S-epimers shifted the Qy peak bathochromically.

Topics: Chlorophyll; Chlorophyll A; Circular Dichroism; Models, Molecular; Molecular Conformation; Optics and Photonics; Solutions; Spectrophotometry, Atomic; Spirulina; Stereoisomerism

Over 4,500 natural product extracts were screened for their abilities to inhibit binding of radiolabeled TGF-alpha to A431 cells; several plant extracts were identified as potential leads with IC50 values of less than 30 micrograms/mL. The active components of one extract were purified to homogeneity and identified as the porphyrin structures, methyl pheophorbides a and b. These compounds inhibited both TGF-alpha receptor binding and the TGF-alpha induced proliferation of NRK-49F cells in soft agar. To construct a structure-function relationship, a series of commercially available porphyrin derivatives was evaluated. The most potent compound, hematoporphyrin IX, inhibited TGF-alpha functions in a dose-dependent fashion with IC50 values slightly lower than the methyl pheophorbides. Further studies revealed that inhibition of TGF-alpha binding was light dependent and that inhibition did not involve direct competition of porphyrins for the TGF-alpha binding site. To determine the specificity of inhibition, the porphyrins were tested in a number of other receptor-ligand assays. TNF-alpha and beta-adrenoceptor bindings were unaffected, whereas IL-1 beta binding to EL-4 membranes and platelet-derived growth factor induced thymidine incorporation in NIH-3T3 cells were both antagonized by the most active porphyrins. Inhibition of TGF-beta binding to NRK-49F cells and TGF-beta-induced growth of AKR-2B cells was also observed. In summary, we report that methyl pheophorbides are naturally occurring, photodynamic antagonists of TGF-alpha, and although the inhibitory properties of these molecules were not confined to TGF-alpha alone, some level of receptor selectivity was observed.

Topics: Animals; Cell Division; Cell Line; Chlorophyll; Cytokines; Drug Synergism; ErbB Receptors; Humans; Plant Extracts; Porphyrins; Receptors, Adrenergic, beta; Recombinant Proteins; Tissue Extracts; Transforming Growth Factor alpha; Transforming Growth Factor beta

Topics: Bacteriochlorophylls; Chemical Phenomena; Chemistry; Chlorophyll; Spectrum Analysis

Topics: Chlorophyll; Chlorophyllides; Chromatography, High Pressure Liquid