title: Determination of 9-cis beta-carotene and zeta-carotene in biological samples.
abstract: Concentrations of 9-cis beta-carotene (9-cis betaC) and zeta-carotene (zetaC) in biological samples may provide crucial information on the biological activities of these carotenoids. However, in high-performance liquid chromatography (HPLC) these carotenoids are often co-eluted. Therefore, there is an urgent need to develop a method for 9-cis betaC and zetaC quantitation. Both 9-cis betaC and zetaC have peak absorbance at 400 and 450 nm, respectively, whereas only 9-cis betaC has peak absorbance at 475 nm. We developed a HPLC method to quantitate 9-cis betaC and zetaC by using peak absorbance ratios. The 9-cis betaC/zetaC peak area was monitored at 475, 450 and 400 nm. The 9-cis betaC was quantified by using absorbance value at 475 nm; zetaC was then calculated from the 9-cis betaC/zetaC peak at 400 nm by subtracting 9-cis betaC contribution at 400 nm using the 400-nm/475-nm peak absorbance ratio of 9-cis betaC (0.39). This method was applied to determine 9-cis betaC and zetaC concentrations in serum and breast milk samples (n=12) from American lactating women and serum and breast adipose tissue samples (n=16) from Korean women with either benign or malignant breast tumors. 9-cis betaC concentrations in serum and breast milk of American women, and serum and adipose tissue of Korean women were 7.1+/-0.8 and 1.1+/-0.2 nM, and 15.6+/-1.1 nM and 0.2+/-0.1 nmol/g, respectively. zetaC concentrations in the above samples were 54.2+/-7.2 and 8.3+/-1.8 nM, and 49.0+/-3.9 nM and 0.3+/-0.1 nmol/g, respectively.
authors.affiliation: Jean Mayer USDA-Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Qin
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Yeum
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Johnson
authors.forename: Norman I
authors.initials: NI
authors.lastname: Krinsky
authors.forename: Robert M
authors.initials: RM
authors.lastname: Russell
authors.forename: Guangwen
authors.initials: G
authors.lastname: Tang
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D000293:Adolescent; D000328:Adult; D001940:Breast / Q000737:chemistry; D005260:Female; D006801:Humans; D008895:Milk, Human / Q000737:chemistry; D015203:Reproducibility of Results; D019207:beta Carotene / Q000032:analysis* / Q000302:isolation & purification; D024321:zeta Carotene / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D024321:zeta Carotene; D019207:beta Carotene