OJPM  Vol.4 No.2 , February 2014
Quantitative analysis of sialic acids in Chinese conventional foods by HPLC-FLD
Author(s) Hongwei Li, Xingdan Fan*

Background: Sialic acids are a family of ninecarbon sugar compounds with carboxylic acyl derivatives. It exists in bacteria, fish, mammals and other living organisms, participates in and regulates many important life events, such as cell recognition, membrane flow, endocytosis and so on. Sialic acid is usually located in the outermost layer of the sugar part of the cell membrane and the key positions of secreted glycoconjugates (glycolipids, glycoprotein and lipopolysaccharide). Sialic acid (Sia) is an important material foundation for variety of the structure and founction of glycoconjugates. Sia has been known as nearly 50 members, including N-acetylneuraminic acid (Neu5Ac), N-glycoulylneuraminic acid (Neu5Gc) and deaminoneuraminic acid (KDN) as its core monomer. The rest of the sialic acids are derived from these three monomers. The contents of Sia in Chinese food products are unknown. Objective: To determine the contents of Sia in raw and cooked red meat, seafood, poultry and so on. Design: The following food products were purchased from a Chinese supermarket: pork, beef, lamb, salmon, cod, tuna, cow milk, cheese, butter, duck, chicken and chicken eggs. Human milk was collected from Xiamen Maternity and Child Health Care Hospital (Xiamen, China). All tissues were homogenized and hydrolyzed with 0.05 M, 0.1 M and 0.2 M TFA for 150 min at 80°C in dark, respectively. The concentrations of Neu5Ac, Neu5Gc and KDN were determined by using HPLC with fluorescence detector. Results: The contents of total Sia (μg/g tissue or μg/mL liquid sample) in Chinese raw meat were highest in lamb (269.60), followed by pork (254.88), duck (200.63), chicken (162.86) and beef (88.03). The percentages of Neu5Gc were 36.08%, 26.48%, 0%, 0% and 28.40%, respectively. Cod contained higher levels of Sia (171.63) than salmon (104.43) and tuna (77.98). Only Neu5Ac was 50 found in detected aquatic product. Egg yolk contained the highest level of Sia (682.04), and a higher level of Sia (390.67) was found in the egg white. Also our result showed that human milk contained extremely high level of Sia (602.55). Neu5Ac was the predominant form of Sia in all the deteced samples. KDN was found in cow milk only among the samples, the content was 1.14 μg/g. Conclusion: The highest content of Sia in examined Chinese foods was found in 56 eggs, followed by lamb, pork, duck, cod, chicken, salmon, beef and tuna. Knowledge of the Sia content in conventional foods may help us to better understand possible medical disorders involving the uptake of the “non-human” Neu5Gc from our diet.

Cite this paper
Li, H. and Fan, X. (2014) Quantitative analysis of sialic acids in Chinese conventional foods by HPLC-FLD. Open Journal of Preventive Medicine, 4, 57-63. doi: 10.4236/ojpm.2014.42009.
[1]   Paton, A.W., Varki, N.M., Paton, J.C., et al. (2009) A dietary non-human sialic acid may facilitate hemolyticuremic syndrome. Kidney International, 76, 140-144.

[2]   Brinkman-Van der Linden, E.C., Sjoberg, E.R., Juneja, L.R., Crocker, P.R., Varki, N. and Varki, A. (2005) Loss of N-glycolylneuraminic acid in human evolution implications for sialic acid recognition by siglecs. Journal of Biological Chemistry, 275, 8633-8640.

[3]   Schachter, H., Montreuil, J. and Jfg, V. (1997) Glycoproteins II. Elsevier, Amsterdam, New York.

[4]   Varki, A. (1992) Diversity in the sialic acids. Glycobiology, 2, 25-40. http://dx.doi.org/10.1093/glycob/2.1.25

[5]   Inoue, S., Lin, S.L., Chang, T., Wu, S.H., Yao, C.W., Chu, T.Y., Troy, F.A. and Inoue, Y. (1998) Identification of free deaminated sialic acid (2-keto-3-deoxy-D-glycero-D-galacto-nononic acid) in human red blood cells and its elevated expression in fetal cord red blood cells and ovarian cancer cells. Journal of Biological Chemistry, 273, 27199-27204. http://dx.doi.org/10.1074/jbc.273.42.27199

[6]   Wang, B. and Brand-Miller, J. (2003) The role and potential of sialic acid in human nutrition. European Journal of Clinical Nutrition, 57, 1351-1369.

[7]   Sizzetoglu, S. (2012) The determination of N-acetylneuraminic acid (Neu5Ac) and N-glycolyl-neuraminic acid (Neu5Gc) types of sialic acids in hematopoietic organ of the silkworm, bombyx moriL (Lepidoptera: Bombycidae). Kafkas üniversitesi Veteriner Fakültesi Dergisi, 18, 147-150.

[8]   Ghoshal, A. and Mandal, C. (2011) A perspective on the emergence of sialic acids as potent determinants affecting Leishmania biology. Molecular Biology International, 2011, 1-14.

[9]   Tangvoranuntakul, P., Gagneux, P., Diaz, S., Bardor, M., Varki, N., Varki, A. and Muchmore, E. (2003) Human uptake and incorporation of an immunogenic nonhuman dietary sialic acid. Proceedings of the National Academy of Sciences of USA, 100, 12045-12050.

[10]   Padler-Karavani, V., Yu, H., Cao, H., et al. (2008) Diversity in specificity, abundance, and composition of anti-Neu5Gc antibodies in normal humans: Potential implications for disease. Glycobiology, 18, 818-830.

[11]   Hedlund, M., Tangvoranuntakul, P., Takematsu, H., Long, J., Housley, G., Kozutsumi, Y., Suzuki, A., Wynshaw-Boris, A., Ryan, A. and Gallo, R. (2007) N-glycolylneuraminic acid deficiency in mice: Implications for human biology and evolution. Molecular and Cellular Biology, 27, 4340.

[12]   Martin, M.J., Martin-Sosa, S., Garcia-Pardo, L.A. and Hueso, P. (2001) Distribution of bovine milk sialoglycoconjugates during lactation. Journal of Dairy Science, 84, 995-1000.

[13]   Wang, B., Brand-Miller, J., McVeagh, P. and Petocz, P. (2001) Concentration and distribution of sialic acid in human milk and infant formulas. American Journal of Clinical Nutrition, 74, 510-515.

[14]   Martin, M.J., Vazquez, E. and Rueda, R. (2007) Application of a sensitive fluorometric HPLC assay to determine the sialic acid content of infant formulas. Analytical Biochemistry, 387, 2943-2949.

[15]   Hara, S., Takemori, Y., Yamaguchi, M., Nakamura, M. and Ohkura, Y. (1987) Fluorometric high-performance liquid chromatography of N-acetyl- and N-glycolylneuraminic acids and its application to their microdetermination in human and animal sera, glycoproteins, and glycolipids. Analytical Biochemistry, 164, 138-145.

[16]   Warren, L. (1959) The thiobarbituric acid assay of sialic acids. Journal of Biological Chemistry, 234, 1971-1975.

[17]   Zanetta, J.P., Pons, A., Iwersen, M., Mariller, C., Leroy, Y., Timmerman, P. and Schauer, R. (2001) Diversity of sialic acids revealed using gas chromatography/mass spectrometry of heptafluorobutyrate derivatives. Glycobiology, 11, 663-676.

[18]   Rohrer, J.S. (2000) Analyzing sialic acids using highperformance anion-exchange chromatography with pulsed amperometric detection. Analytical Biochemistry, 283, 3-9. http://dx.doi.org/10.1006/abio.2000.4643

[19]   Siskos, P.A. and Spyridaki, M.H. (1999) Determination of sialic acids in biological fluids using reversed-phase ionpair high-performance liquid chromatography. Journal of Chromatography B: Biomedical Sciences and Applications, 724, 205-212.

[20]   Powell, L.D. and Hart, G.W. (1986) Quantitation of picomole levels of N-acetyl- and N-glycolylneuraminic acids by a HPLC-adaptation of the thiobarbituric acid assay. Analytical Biochemistry, 157, 179-185.

[21]   Anumula, K.R. (1995) Rapid quantitative determination of sialic acids in glycoproteins by high-performance liquid chromatography with a sensitive fluorescence detection. Analytical Biochemistry, 230, 24-30.

[22]   Koketsu, M., Sakuragawa, E., Linhardt, R. and Ishihara, H. (2003) Distribution of N-acetylneuraminic acid and sialylglycan in eggs of the Silky fowl. British Poultry Science, 44, 145-148.

[23]   Bardor, M., Nguyen, D., Diaz, S. and Varki, A. (2005) Mechanism of uptake and incorporation of the nonhuman sialic acid N-glycolylneuraminic acid into human cells. Journal of Biological Chemistry, 280, 4228-4237.