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53.
用原子吸收分光光度法测定了三个不同产地橘红的元素含量,并比较了它们之间各种元素含量的差异。结果表明,化州橘红的Cu,Ca含量显著低于其它产地橘红,而其它元素含量差异不大。 相似文献
54.
H. L. L. M. van Leengoed N. van der Veen A. A. C. Versteeg R. Ouellet J. E. van Lier W. M. Star 《Photochemistry and photobiology》1993,58(2):233-237
Abstract— The fluorescence pharmacokinetics of a series of metallosulfophthalocyanines, chelated with either aluminum or zinc and sulfonated to different degrees, was studied by fluorescence measurements in vivo . Dyes were administered systemically to female WAG/RIJ rats with an isogeneic mammary carcinoma transplanted into the subcutis in a transparent observation chamber located on their backs. Following an intravenous injection of 2.5 μmol/ kg of the dye, fluorescence dynamics was observed up to 7 h postinjection. The phthalocyanines were excited at 610 nm with a power density of 0.1 mW/cm2 without causing photodynamic damage to the vasculature. Fluorescence was detected above 665 nm using a fluorescence imaging system based on an image intensifier. Dye retention in the blood vessels and tumor tissue was expressed as ratios relative to the fluorescence signal of the surrounding subcutaneous tissue. Phthalocyanincs chelated with aluminum gave the highest fluorescence signal with tumor-over-subcutis ratios of up to a value of 4. The zinc complexes exhibited the highest vascular-over-subcutis ratios with maximum values exceeding a value of 6. They also displayed the longest retention times in the vascular system of well over 7 h. Overall, decreasing the degree of sulfonation of the metallophthalocyanines results in lower tumor-over-normal tissue fluorescence ratios, and furthermore aluminum-based dyes seem superior tumor localizers over zinc-based dyes. The advantages of phthalocyanines over porphyrins with respect to tumor localization and photodynamic therapy are discussed. 相似文献
55.
Interactions of organic peroxides (R'OOR) and hydroperoxides (R'OOH), including H2O2, with excited triplet and singlet state metallophthalocyanines (MPc, M = Zn, Al) have been studied by T-T absorption decay and fluorescence quenching. The ensuing photochemical processes result in decomposition of (hydro)peroxides as assessed by photo-EPR (electron paramagnetic resonance) and spin trapping. In argon-saturated apolar solutions and low MPc concentrations, alkoxyl free radicals (*OR) were identified as the primary products of (hydro)peroxide breakdown. Similarly, photosensitized decomposition of symmetric disulfides results in the formation of sulfur-centered radicals. In air-free aqueous solutions, ROOH photosensitization always gave rise to a mixture of hydroxyl and peroxyl radical (*OOR) adducts in varying molar ratios. At high MPc concentrations, both in polar and in apolar solutions, the most abundant products of ROOH decomposition were identified as *OOR. This indicates a change in the predominant interaction pathway, most likely mediated by MPc exciplexes and involving H-atom abstraction from ROOH by MPc-cation radicals. The prevalence of MPc singlet vs. triplet state interactions was confirmed by the much higher singlet quenching rate constants (log kq up to 9.5; vs. log kT < or = 4.5). In contrast to the triplet quenching, singlet quenching rates were found to depend on the (hydro)peroxide structure, following closely the trend of varying *OR yields for different substrates. Thermodynamic calculations were performed to correlate experimental results with models for electronic energy and charge transfer processes in agreement with the Marcus theory (Rhem and Weller approximation) and Savéant's model for a concerted dissociative electron transfer mechanism. 相似文献
56.
J.-L. Ravanat M. Berger F. Benard R. Langlois R. Ouellet J. E. van Lier J. Cadet 《Photochemistry and photobiology》1984,39(6):809-814
Abstract
The photodynamic properties of the di-and tetrasulfonated zinc and aluminium phthalocyanines and a tetrasulfonated aluminium napththalocyanine were studied using 2'-deoxyguanosine as a DNA model compound. The major photooxidation products of this nucleoside were identified and classified according to their formation through a radical mechanism (type I) or a singlet oxygen mediated mechanism (type II). The major type I product was obtained and identified as 2,2-diamino [(2-deoxy-β- d - erythro pentofuranosyl)-4-amino]-5( 2H )-oxazolone. Two major type II products were characterized as the 4R* and 4S* diastereomers of 9-(2-deoxy-β- d - erythro pentofuranosyl)-7,8-dihydro-4-hydroxy-8-oxoguanine. In addition a third product, also resulting from a type II photooxidation, was identified as 8-oxo-7,8-dihydro-2'-deoxyguanosine. Quantification of these products provided a means to estimate the contribution of type I and type II pathways during the phthalocyanine and naphthalocyanine mediated photooxidation of 2'-deoxyguanosine, confirming the major role of singlet oxygen in these processes. 相似文献
The photodynamic properties of the di-and tetrasulfonated zinc and aluminium phthalocyanines and a tetrasulfonated aluminium napththalocyanine were studied using 2'-deoxyguanosine as a DNA model compound. The major photooxidation products of this nucleoside were identified and classified according to their formation through a radical mechanism (type I) or a singlet oxygen mediated mechanism (type II). The major type I product was obtained and identified as 2,2-diamino [(2-deoxy-β- d - erythro pentofuranosyl)-4-amino]-5( 2H )-oxazolone. Two major type II products were characterized as the 4R* and 4S* diastereomers of 9-(2-deoxy-β- d - erythro pentofuranosyl)-7,8-dihydro-4-hydroxy-8-oxoguanine. In addition a third product, also resulting from a type II photooxidation, was identified as 8-oxo-7,8-dihydro-2'-deoxyguanosine. Quantification of these products provided a means to estimate the contribution of type I and type II pathways during the phthalocyanine and naphthalocyanine mediated photooxidation of 2'-deoxyguanosine, confirming the major role of singlet oxygen in these processes. 相似文献
57.
不同产地及不同生长期高良姜中总黄酮的测定 总被引:2,自引:0,他引:2
不同产地及不同生长期高良姜中总黄酮的测定*罗辉张建和莫丽儿(广东医学院化学教研室湛江524023)关键词高良姜总黄酮柱层析-分光光度法中图分类号O657.32高良姜系姜科植物高良姜AlpiniaoficinarumHance的根状茎,其药性温中散寒,... 相似文献
58.
R. Langlots H. Ali N. Brasseur J. R. Wagner J. E. van Lier 《Photochemistry and photobiology》1986,44(2):117-123
Abstract— Sulfonated phthalocyanine and a series of its metal chelates in combination with red light irradiation led to the degradation of L-tryptophan in oxygenated aqueous solution. The photoproducts and the rate of transformation of L-tryptophan are compared with hematoporphyrin and rose bengal sensitized photooxidation. In all cases the primary photoproducts are characterized as cis and trans -3a-hydroperoxy-l,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid. Support for the involvement of singlet excited oxygen is obtained from azide inhibition and the formation of the specific singlet oxygen product with cholesterol. We observed the contribution of another pathway in the case of the manganese complex. 相似文献
59.
Benoit Paquette Hasrat Ali Rejean Langlois Johan E. van Lier 《Photochemistry and photobiology》1990,51(3):313-317
The phototoxicity of sulfonated aluminum naphthalocyanines towards V-79 Chinese hamster cells is investigated. The disulfonated naphthalocyanine exhibits similar photostability, but better cell penetrating properties than the tetrasulfonated dyes. The capacity of the naphthalocyanines to generate singlet oxygen is comparable to that of the corresponding phthalocyanines. However, in contrast to the phthalocyanine dyes, the sulfonated aluminum naphthalocyanines show very little phototoxicity towards the V-79 cells, suggesting close association with non-vital cell constituents or extensive formation of photoinactive adducts and aggregates. 相似文献
60.
J.-L. Ravanat M. Berger F. Benard R. Langlois R. Ouellet J. E. van Lier J. Cadet 《Photochemistry and photobiology》1992,55(6):809-814
Abstract— The photodynamic properties of the di-and tetrasulfonated zinc and aluminium phthalocyanines and a tetrasulfonated aluminium napththalocyanine were studied using 2'-deoxyguanosine as a DNA model compound. The major photooxidation products of this nucleoside were identified and classified according to their formation through a radical mechanism (type I) or a singlet oxygen mediated mechanism (type II). The major type I product was obtained and identified as 2,2-diamino [(2-deoxy-β- d - erythro pentofuranosyl)-4-amino]-5( 2H )-oxazolone. Two major type II products were characterized as the 4R* and 4S* diastereomers of 9-(2-deoxy-β- d - erythro pentofuranosyl)-7,8-dihydro-4-hydroxy-8-oxoguanine. In addition a third product, also resulting from a type II photooxidation, was identified as 8-oxo-7,8-dihydro-2'-deoxyguanosine. Quantification of these products provided a means to estimate the contribution of type I and type II pathways during the phthalocyanine and naphthalocyanine mediated photooxidation of 2'-deoxyguanosine, confirming the major role of singlet oxygen in these processes. 相似文献