Assistance of human serum albumin to photo-sensitized inactivation of Saccharomyces cerevisiae with axially pyridinio-bonded P-porphyrins.
As singlet-oxygen ((1)O2) sensitizer, water-soluble P-porphyrins (1) were prepared by the modification of axial ligands of tetraphenylporphyrinatophosphorus by N-alkyl-pyridinium group to give bis[3-(1-alkyl-4-pyridinio)propoxo]tetraphenylporphyrinatophosphorus(V) (alkyl=hexyl (1a) and butyl (1b)) and bis[5-(3-alkyl-1-pyridinio)-3-oxapentyloxo] tetraphenylporphyrinatophosphorus(V) (alkyl=hexyl (1c), butyl (1d), and ethyl (1e)). The quantum yields (ΦΔ) for the formation of (1)O2 were extremely high (e.g. ΦΔ=0.88 (1a) and 0.87 (1c)). The 1 could bind human serum albumin (HSA) with high binding constants to produce a complex of HSA with 1 (1/HSA). Here, inactivation of Saccharomyces cerevisiae (yeast) was examined using the complex of HSA (400nM) with 1 (20-50nM) under visible-light irradiation. The bactericidal activity of 1 was evaluated by half-life (T1/2 in min) which was time required to be reduced to one-half initial concentration of yeasts. Under irradiation in the presence of HSA, minimum concentrations ([P]) of 1 were adjusted as T1/2 became the values among 0-120min. The [P] values were determined to be 20nM for 1a, 30nM for 1b, and 50nM for 1c-1e. The 1/HSA sterilized yeast with 12-36min of T1/2 when the concentration of 1 was set to [P]. In the photo-activation in the absence of HSA at the concentration of [P] of 1, however, the T1/2 values of 1a, 1b, 1d, and 1e were >120min and T1/2 of 1c was 44min. Thus, the complexation of 1 with HSA apparently enhanced the bactericidal activity of 1. This is the first finding on the assistance of HSA to the photo-inactivation of yeast cell by porphyrins.
Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Gakuen-Kibanadai, Miyazaki 889-2192, Japan. Electronic address: jmatsu@cc.miyazaki-u.ac.jp.
Jin
J
Matsumoto
Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Gakuen-Kibanadai, Miyazaki 889-2192, Japan.
Yuya
Y
Kai
Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Gakuen-Kibanadai, Miyazaki 889-2192, Japan.
Haruhiko
H
Yokoi
Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
Shigetoshi
S
Okazaki
Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Gakuen-Kibanadai, Miyazaki 889-2192, Japan.
Masahide
M
Yasuda
D006207:Half-Life; D006801:Humans; D008027:Light; D008856:Microscopy, Fluorescence; D017319:Photosensitizing Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D011166:Porphyrins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000187:drug effects*; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D026082:Singlet Oxygen / Q000737:chemistry; D012995:Solubility; D014867:Water / Q000737:chemistry
D017319:Photosensitizing Agents; D011166:Porphyrins; D012709:Serum Albumin; D014867:Water; D026082:Singlet Oxygen
Alkyl pyridinium; Human serum albumin; Photo-inactivation; Photosensitizer; Water-soluble porphyrin