Toxicologic Evaluation of Cellulon™ Fiber;Genotoxicity,Pyrogenicity,Acute and Subchronic Toxicity

Abstract

Cellulon^TM fiber, a cellulose produced by a bacterial fermentation process employing a strain of Acetobacter aceti subsp. xylinum, was tested for genotoxicity in four assays: (1) microbial reverse mutation assay in Salmonella typhimurium (Ames assay), (2) an assay for chromosomal aberrations in Chinese hamster ovary (CHO) cells, (3) an assay for induction of unscheduled DNA synthesis (UDS) in rat primary hepatocytes, and (4) the CHO/HGPRT forward mutation assay. Each assay was conducted at a wide range of dose levels, both with and without metabolic activation (assay 1, 2, and 4). Test results gave no indication that Cellulon fiber possessed any genotoxic potential. The pyrogenicity of five batches of Cellulon fiber was tested in the Limulus Amebocyte Lysate assay, gel-clot method. Test results were negative for the presence of gram-negative bacterial endotoxin. The primary eye and dermal irritation potential of Cellulon fiber were examined in New Zealand White rabbits. The Draize method was employed to evaluate and grade ocular and dermal irritation as a result of test material administration. Test results indicated that Cellulon fiber is a minor ocular irritant up to 1 hour postadministration. However, the resultant irritation was considered to be mechanical and related to the dry, granular form of the test material. In addition, test results indicated that Cellulon fiber is not a dermal irritant in the rabbit. The acute oral toxicity of Cellulon fiber was determined in Sprague-Dawley rats, and the LD₅₀ was found to be greater than 2000 mg/kg of body weight. The subchronic toxicity of Cellulon fiber was examined in Sprague-Dawley rats fed diets containing 0, 5, and 10% Cellulon fiber or microcrystalline cellulose for 13 weeks. No dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or pathologic lesions were observed. The results of these studies indicate that Cellulon fiber and microcrystalline cellulose are toxicologically equivalent and that Cellulon fiber does not possess genotoxic potential, is nonpyrogenic, and that animals are not adversely affected by acute or subchronic exposure to Cellulon fiber.

References

1. Banzon, J.A. , Gonzalez, O.N. , Deleon, S.Y. , and Sanchez, P.C. (1990). Nata de Coco, in: Coconut as Food. J. A. Banzon , O. N. Gonzalez , S. Y. DeLeon , and P. C. Sanchez (ed). Quezon City, Philippines: Phillipine Coconut Research and Development Foundation Inc.

2. Terasima, T. , and Tolmach, L.J. (1961). Changes in x-ray sensitivity of HeLa cells during the division cycle. Nature 190, 1210–1211.

3. Evans, H.J. (1962). Chromosomal aberrations produced by ionizing radiation. Int. Rev. Cytol. 13, 221–321.

4. Williams, G.M. (1977). Detection of chemical carcinogens by unscheduled DNA synthesis in rat liver primary cell culture. Cancer Res. 37, 1845–1851.

5. Williams, G.M. (1980). The detection of chemical mutagens-carcinogens by DNA repair and mutagenesis in liver cultures, in: Chemical Mutagens, F. de Serres and A. Hollander (eds). New York: Plenum Press, 6, 61–79.

6. Butterworth, B.E. , Ashby, J. , Bermudez, E. , Casciano, D. , Mirsalis, J. , Probst, G. , and Williams, G. (1987). A protocol and guide for the in vitro rat hepatocyte DNA-repair assay. Mutat. Res. 189, 113–121.

7. Hsie, A.W. , Brimer, P.A. , Mitchell, T.J. , and Gossiee, D.G. (1975). Dose-response relationship for ethyl methanesulfonate-induced mutations at the hypoxanthine-guanine phosphoribosyl transferase locus in Chinese hamster ovary cells. Somat. Cell. Genet. 1, 247–261.

8. Hsie, A.W. , Casciano, D.A. , Couch, D.B. , Krahn, D.F. , O'Neil, J.P. , and Whitfield, B.L. (1981). The use of Chinese hamster ovary cells to quantify specific locus mutation and to determine mutagenicity of chemicals. Mutat. Res. 86, 193–214.

9. Myhr, B.C. , and DiPAOLO, J.A. (1978). Mutagenesis of Chinese hamster cells in vitro by combination treatments with methyl methanesulfonate and N-acetoxy-2-acetylaminofluorene. Cancer Res. 38, 2539–2543.

10.

10. Draize, J.H. (1959). Appraisal of the Safety of Chemicals in Foods, Drugs, and Cosmetics—Dermal Toxicity. Austin, TX: Association of Food Drug Officials of the U.S., pp. 46–59.

11.

11. Dunnett, C.W. (1955). A multiple comparison procedure for comparing several treatments with a control. J. Am. Stat. Assoc. 50, 1096–1121.

12.

12. Dunnett, C.W. (1964). New tables for multiple comparisons with a control. Biometrics 20, 482–491.

13.

13. Levene, H. (1960). Robust tests for equality of variances, in: Contributions to Probability and Statistics. I. Olkin (ed). Palo Alto: Stanford University Press, pp. 278–292.