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Objective To investigate the photodynamic antitumor activity and chemical characteristics of pheophorbide A (PPBa)in vitro. Methods Breast cancer cells (MCF-7), lung cancer cells (A549), cervical cancer cells (HeLa), and three kinds of hepatoma cells (HepG2, hep3B and sk-Hep1) were planted in 96-well plates.The effects of light and dark toxicity, light intensity, and drug concentration on the phototoxicity of PPBa were investigated by MTT, and the uptake of PPBa was observed by Hoechst staining under a confocal microscope.The production of singlet oxygen was observed by flow cytometry and confocal microscopy with the reactive oxygen species detection kit.The photobleaching of PPBa was investigated by measuring the absorbance by a microplate reader according to the luminescence characteristics of PPBa. Results PPBa showed strong phototoxicity and low dark toxicity to six kinds of cancer cells, and IC50 values to cancer cells were as follows: MCF-7:1.033 μmol/L, A549:1.911 μmol/L, HeLa: 2.319 μmol/L, HepG2:2.015 μmol/L, Hep3B: 2.089 μmol/L, sk-Hep1:2.467 μmol/L.The main uptake site of PPBa was the cytoplasm.The production of singlet oxygen was strongly dependent on the administration concentration, and photobleaching was very low. Conclusion For the six kinds of cancer cells, PPBa has the highest phototoxicity to breast cancer cells (MCF-7), with excellent properties and ideal photosensitizer characteristics.
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Objective To analyze the physicochemical properties and photothermal properties after introducing a certain proportion of phaeophorbide into polyvinyl alcohol-lipoic acid polymer.Methods The "one-step" method was adopted to synthesize the PVA27K-4 ％LA-10 ％ Pheide (PLP) polymer.The laser particle diameter tester was used to detect the particle size,polydispersity index and ζ potential of PLP nanoparticle (PLPN);the morphology was observed under transmission electron microscope (TEM);the in vitro fluorescent and photothermal properties were investigated by using spectrophotometric method and infrared thermal imager;the ovarian-cancer nude mice models were established and the preliminary in vivo experiment evaluation was performed.Results The synthetic PLP polymer could self-assembly form spherical PLPN in aqueous environment,which showed the tightly spherical structure under TEM.The average particle diameter,polydispersity index and ζ potential were (22.92 ± 9.00)nm,(0.117±0.056) and (-25.43±0.77)mV respectively.The fluorescence intensity of PLPN in PBS solution was significantly lower than that in SDS solution (P＜0.05).However,the temperature of the PBS solution of PLPN was significantly higher than that of the SDS solution after exposure to the near infrared light (P＜0.05).In the model of tumor-bearing nude mice,PLPN could targetaccumulated in the tumor site.The temperature in the tumor site was significantly increased after exposure to the near infrared light,which could kill tumor cells.Conclusion PLPN could emit red fluorescence,and could target-accumulated in tumor site and conduct the in vivo image,which has significant photothermal conversion properties in vivo and in vitro,and can effectively inhibit the tumor growth in vivo.
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Objective] To explore a new method of synthesis of resveratrol oligmer induced by photosensitizers, further analyze its free radical scavenging activity and analgesic activity. [Method] Resveratrol was dispersed in pH 7.4 phosphate buffer solution, mixed with pheophorbide, then illuminated by laser at 630nm. The oligmers in the filtrate were analyzed by HPLC-MS and isolated by preparative liquid chromatography. Free radical scavenging activity was determined by DPPH and ABTS method, and the analgesic effect was measured by hot plate test and acetic acid writhing test in mice. [Result] A new peak occurred and reached stable in reactive solution after 20 min illumination. It was identified as the dimer of resveratrol with conversion of 35%. Its concentrations on inhibition of 50% DPPH and ABTS radical were respectively 230 μg·mL-1 and 273 μg·mL-1. It reached maximum pain threshold at 180 min, and the inhibition rate of writhing number was 62.6% with better effects than resveratrol. [Conclusion] Reseratrol can be polymerized to the dimer after pheophorbide excited by red light, the resveratrol and its dimer both have the ability of eliminating free radicals and analgesic effects, but the dimer has the stronger activity.
ABSTRACT
Del extracto de éter de petróleo de hojas de Uncaria guianensis (Rubiaceae), se aisló un compuesto tipo clorina denominado éster etílico de feoforbida a y una mezcla de esteroles conocidos como ß-sitosterol y estigmasterol. Sus estructuras fueron elucidadas por análisis detallado de RMN, incluyendo técnicas bidimensionales, y por comparación con datos reportados en la literatura. Posteriormente, se evaluó la actividad antibacteriana al éster etílico de feoforbida a contra dos cepas Gram(+): S. aureus ATCC 6538 y E. faecalis ATCC 29212 y contra tres cepas Gram (-): E. coli ATCC 25922, S. typhimurium ATCC 14028s y S. typhimurium MS7953. Se encontró actividad significativa contra S. aureus, E. faecalis, E. coli y S. tiphymurium MS7953.
A chlorin compound, pheophorbide a ethyl ester and a mixture of sterols known as ß-sitosterol and stigmasterol, were isolated from the petroleum ether extract of Uncaria guianensis (Rubiaceae) leaves. Their structures were elucidated by detailed analysis of NMR spectra, including bidimensional techniques and by comparison with literature data. The antibacterial activity for the pheophorbide a ethyl ester was evaluated against two Gram (+) strains: S. aureus ATCC 6538 y E. faecalis ATCC 29212 and three Gram (-) strains: E. coli ATCC 25922, S. typhimurium ATCC 14028s y S. typhimurium MS7953S. aureus ATCC 6538 and E. fecalis ATCC 29212, finding significant activity against S. aureus 6538, E. faecalis 29212, S. tiphymurium MS7953 and E. coli 25922.
Subject(s)
Rubiaceae , Uncaria , Anti-Bacterial AgentsABSTRACT
A method for the preparation of pheophorbide a ( a novel photosensitizer for tumor photolocalization and photodynamic therapy) from silkworm excrement oily chlorophyll is reported for the first time. The chromatographic, sectroscopic and photochemical properties of pheophorbide a were studied, and its distribution in tissues of S180 tumor-bearing mice was determined. The UV/vis spectrum of the obtained pheophorbide a was identical with that reported by other authors, but it was still found to contain two components (probably two optical isomers) by HPLC analysis and 1H-NMR spectrometry. The results of a preliminary study on its distribution in tumor-bearing mice showed that it was accumulated selectively in tumor tissues after intravenous injection and at 24 hours after drug administration the tumor to skin ratio rose to as high as 15. These results suggest that it might be a a promising photosensitizer.