Biological safety of liposome-fullerene consisting of hydrogenated lecithin, glycine soja sterols, and fullerene-C60 upon photocytotoxicity and bacterial reverse mutagenicity.
Various water-soluble derivatives of fullerene-C60 (C60) have been developed as detoxifiers for reactive oxygen species (ROS), whereas C60 incorporated in liposome (Lpsm) has not been reported yet. We prepared the liposome-fullerene (0.2% aqueous phase, Lpsm-Flln) which was composed of hydrogenated lecithin, glycine soja (soybean) sterols, and C60 in the weight ratio of 89.7:10:0.3, then examined the photocytotoxicity and bacterial reverse mutagenicity, as comparing with the Lpsm containing no C60. Photocytoxicity of Lpsm-Flln or Lpsm was examined using Balb/3T3 fibroblastic cells at graded doses of 0.49-1000 microg/mL under the condition of UVA- or sham-irradiation. The cells were irradiated with UVA (5 J/cm2, 320-400 nm, lambda max = 360 nm) at room temperature for 50 min. The resultant cell viability (% of control) did not decrease dose-dependently to 50% or less regardless of the UVA-irradiation. These results show that Lpsm-Flln or Lpsm does not possess photocytotoxicity to Balb/3T3 fibroblasts, and Lpsm-Flln may not exert a UVA-catalytic ROS-increasing action. A possibility for the reverse mutation by Lpsm-Flln or Lpsm was examined on four histidine-demanding strains of Salmonella typhimurium and a tryptophan-demanding strain of Escherichia coli. As for the dosages of Lpsm-Flln or Lpsm (313-5000 microg/plate), the dose-dependency of the number of reverse mutation colonies of each strain did not show a twice or more difference versus the negative control regardless of the metabolic activation, and, in contrast, marked differences for five positive controls (sodium azide, N-ethyl-N'-nitro-N-nitrosoguanidine, 2-nitrofluorene, 9-aminoacridine, and 2-aminoanthracene). The growth inhibition of bacterial strains and the deposition of Lpsm-Flln or Lpsm were not found. As a result, the bacterial reverse mutagenicity of Lpsm-Flln or Lpsm was judged to be negative under the conditions of this test. Thus, Lpsm-Flln and Lpsm may not give any significant biological toxic effects, such as photocytotoxicity and bacterial reverse mutagenicity.
Kato
S
S
Laboratory of Cell-Death Control BioTechnology, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima, Japan.
Aoshima
H
H
Saitoh
Y
Y
Miwa
N
N
D002264:Carboxylic Acids / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity*; D002470:Cell Survival; D037741:Fullerenes / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity*; D005998:Glycine / Q000737:chemistry; D054709:Lecithins / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity*; D009152:Mutagenicity Tests; D013024:Soybean Oil / Q000737:chemistry; D013261:Sterols / Q000737:chemistry; D014466:Ultraviolet Rays
C416673:C60 carboxyfullerene; D002264:Carboxylic Acids; D037741:Fullerenes; D054709:Lecithins; D008081:Liposomes; D013261:Sterols; D013024:Soybean Oil; D005998:Glycine