The Journal of Toxicological Sciences
Online ISSN : 1880-3989
Print ISSN : 0388-1350
ISSN-L : 0388-1350
Original Article
Ninety-day oral toxicity study of rhamsan gum, a natural food thickener produced from Sphingomonas ATCC 31961, in Crl:CD(SD)IGS rats
Akihiro HagiwaraNorio ImaiYuko DoiMasashi SanoSeiko TamanoToshio OmotoIwao AsaiKazuo YasuharaShim-mo Hayashi
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2010 Volume 35 Issue 4 Pages 493-501


This study was designed to evaluate and characterize any subchronic toxicity of rhamsan gum, a polysaccharide produced from Sphingomonas strain ATCC 31961, when administered to both sexes of Crl:CD(SD)IGS rats at dietary levels of 0 (control), 0.5, 1.5, and 5.0% (10 rats/sex/group). During the study, the treatment had no adverse effects on clinical signs, survival, body weights and food and water consumption, or on findings of urinalysis, ophthalmology, hematology, or blood biochemistry.  Examination of gross pathology and histopathology exhibited no differences of toxicological significance between control and treated rats. Increased relative cecum (filled) and cecum (empty) weights, evident in males of 1.5% group and both sexes of the 5.0% group, were considered to be a physiological adaptation. Thus, the results indicated the toxic level of rhamsan gum to be more than 5.0%, and the no-observedadverse- effect level (NOAEL) was concluded to be 5.0% (3,362 mg/kg body weights/day for males, and 4,304 mg/kg body weights/day for males) from the present study.

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© 2010 The Japanese Society of Toxicology
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