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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #218212
Title: Determination of 9-cis beta-Carotene and zeta-Carotene in Biological Samples

Author
item Tang, Guang-Wen
item Yeum, Kyung-Jin
item Johnson, Elizabeth
item QIN, JIAN - JM USDA HNRCA @ TUFTS
item Russell, Robert
item KRINSKY, NORMAN - JM USDA HNRCA @ TUFTS

Submitted to: Journal of Nutritional Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2007
Publication Date: N/A
Citation: N/A

Interpretive Summary: Carotenoids represent a large group of phytochemicals that may contribute to health and disease prevention. It is generally accepted that serum carotenoid concentrations are markers of recent fruit and vegetable intake, whereas tissue carotenoid levels are indicators of longer-term carotenoid consumption patterns. The major beta -carotene (beta C) isomer in human serum is all-trans beta C, with small or negligible amounts of 13-cis beta C and 9-cis beta C . However, there are considerable amounts of 9-cis beta C and 13-cis beta C present in various human tissues. It has been suggested that the distribution pattern of beta C isomers in various organs may explain, in part, tissue-specific functions of beta C. zeta Carotene (zeta C) is precursor of lycopene, which is widely distributed in fruits and vegetables such as tomatoes and tomato-based products, apricot, cantaloupe, and oranges, and in human biological samples such as blood and milk. Supplementation with zeta C-containing foods increases zeta C levels in human serum and human breast tissue. Concentrations of 9-cis' beta C and zeta C in biological samples may provide crucial information on 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' beta C and zeta C quantitation. Both 9-cis' beta C and zeta C have peak absorbance at 400 and 450 nm, whereas only 9-cis' beta C has peak absorbance at 475 nm. We developed a HPLC method to quantitate 9-cis' beta C and zeta C by using peak absorbance ratios. The 9-cis' beta C/ zeta C peak area was monitored at 475, 450 and 400 nm. The 9-cis' beta C was quantified by using absorbance value at 475 nm; zeta C was then calculated from the 9-cis' beta C/ zeta C peak at 400 nm by subtracting 9-cis beta C contribution at 400 nm using the 400 nm/475 nm peak absorbance ratio of 9-cis' beta C (0.39). This method was applied to determine 9-cis' beta C and zeta C 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 beta C concentrations in serum and breast milk of American women, and serum and adipose tissue of Korean women were 7.1 +/- 0.8 nM and 1.1 +/- 0.2 nM, and 15.6 +/- 1.1 nM and 0.2 +/- 0.1 nmol/g, respectively. zeta C concentrations in above samples were 54.2 +/- 7.2 nM and 8.3 +/- 1.8 nM, and 49.0 +/- 3.9 nM and 0.3 +/- 0.1 nmol/g, respectively.

Technical Abstract: Concentrations of 9-cis beta-carotene (9-cis' beta C) and zeta-carotene (zeta C) in biological samples may provide crucial information on 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' beta C and zeta C quantitation. Both 9-cis' beta C and zeta C have peak absorbance at 400 and 450 nm, whereas only 9-cis' beta C has peak absorbance at 475 nm. We developed a HPLC method to quantitate 9-cis' beta C and zeta C by using peak absorbance ratios. The 9-cis' beta C/ zeta C peak area was monitored at 475, 450 and 400 nm. The 9-cis' beta C was quantified by using absorbance value at 475 nm; zeta C was then calculated from the 9-cis' beta C/ zeta C peak at 400 nm by subtracting 9-cis beta C contribution at 400 nm using the 400 nm/475 nm peak absorbance ratio of 9-cis' beta C (0.39). This method was applied to determine 9-cis' beta C and zeta C 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 beta C concentrations in serum and breast milk of American women, and serum and adipose tissue of Korean women were 7.1 +/- 0.8 nM and 1.1 +/- 0.2 nM, and 15.6 +/- 1.1 nM and 0.2 +/- 0.1 nmol/g, respectively. zeta C concentrations in above samples were 54.2 +/- 7.2 nM and 8.3 +/- 1.8 nM, and 49.0 +/- 3.9 nM and 0.3 +/- 0.1 nmol/g, respectively.