title: Effects of a rhubarb (Rhei rhizoma) solution and its fractions on the formation of calcium phosphate precipitates.
abstract: Inhibitory effects of a rhubarb (Rhei rhizoma) solution and its fractions on the formation of calcium phosphate precipitates were studied. The rhubarb solution inhibited both the amorphous calcium phosphate (ACP) formation and the rate of hydroxyapatite (HAP) transformation, and extended the induction time. When the solution was fractionated using membrane filters, a filtrate with the molecular weight between 3 and 10 kDa (with 2/3 recovery of polyphenols) was found to be responsible for both the ACP formation and the extension of the induction time. Another filtrate with the molecular weight below 3 kDa (with 1/3 recovery of polyphenols) may be responsible for the inhibition of both the ACP formation and the rate of HAP transformation, and the extension of the induction time. When the extract of rhubarb was fractionated using a Sephadex LH-20 column chromatography, fraction IV greatly inhibited the formation of calcium phosphate precipitates, while fractions I, II and III slightly inhibited that reaction. Our finding suggests that fraction IV may contain useful substance(s) for the prevention of oral calcium phosphate precipitation (calculus formation). However, strong calcium chelating properties would limit the concentration that could be safely employed.
authors.affiliation: Department of Oral Biochemistry, Fukuoka Dental College, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hidaka
authors.forename: H
authors.initials: H
authors.lastname: Nishimura
authors.forename: K
authors.initials: K
authors.lastname: Nakajima
authors.forename: S Y
authors.initials: SY
authors.lastname: Liu
mesh_terms: D000704:Analysis of Variance; D002118:Calcium / Q000737:chemistry; D002130:Calcium Phosphates / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002614:Chelating Agents / Q000737:chemistry; D005591:Chemical Fractionation; D011232:Chemical Precipitation; D003728:Dental Calculus / Q000517:prevention & control; D017886:Durapatite / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry*; D010946:Plants, Medicinal; D012250:Rheum / Q000737:chemistry*; D018709:Statistics, Nonparametric
chemical_list: D002130:Calcium Phosphates; D002614:Chelating Agents; D010936:Plant Extracts; C485828:alpha-tricalcium phosphate; C519480:amorphous calcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; D017886:Durapatite; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous; D002118:Calcium