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3. safety evaluation > (2) Cell Tocixity Test

Cell Toxicity Test of earthplusTM extraction liquid
(Colony formation inhibiting test) [Re: B010757 ]
Consignor: Shinshu Ceramics Co., Ltd.
Study director: 20/01/2003 Mr.Seiji Ootake
Mitsubishi Chemical Safety Science Institute
Kashima Institute Toxicology laboratory
Observation and Conclusion
It was examined the Cell Toxicity of earthplusTM by Colony formation inhibiting test with V79 Cell.
From the result of Colony formation test, the colony formation rate for the plate which is treated with test substance extraction liquid, dropped by depending on the concentration of the extraction liquid and it was concluded that the test substance (earthplusTM) shows the toxicity.
The IC50 of the test substance extraction liquid was 53.5 % (95% Confidence limit was 47.3 to 63.0%). The figure is lower compared to IC50 of Standard Material B (69.7%) but the figure is higher compared to Standard Material A. Therefore the cytotoxic effect of the test substance is stronger than Standard material B but weaker than Standard material A.
In addition,
The I C50 of standard material A is below 7% and material B is below 70 %.
There was no difference for the colony formation between the plates which is added 100% extraction liquid of negative material and the not added one.
The result of using standard material A, B and negative material met the requirement of applicable guide line5.5. Therefore the test condition is considered appropriate.

It was concluded that earthplusTM shows toxicity on V79 Cell and I C50 was 53.5%(95% Confidence limit was 47.3 to 63.0%). The cytotoxic effect of earthplusTM for the V79 Cell is stronger than Standard material B but weaker than Standard material A.