Synthesis and structural elucidation of glutathione and N-aceyl-cysteine conjugates of 5-aminosalicylic acid
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Synthesis and structural elucidation of glutathione and N-aceyl-cysteine conjugates of 5-aminosalicylic acid. / Jensen, J.; Cornett, Claus; Olsen, C. E.; Tjornelund, J.; Hansen, S. H.
In: European Journal of Pharmaceutical Sciences, Vol. 1, No. 3, 1993, p. 143-150.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Synthesis and structural elucidation of glutathione and N-aceyl-cysteine conjugates of 5-aminosalicylic acid
AU - Jensen, J.
AU - Cornett, Claus
AU - Olsen, C. E.
AU - Tjornelund, J.
AU - Hansen, S. H.
PY - 1993
Y1 - 1993
N2 - The ability of 5-aminosalicylic acid (5-ASA) to be oxidized to a quinone monoimine compound capable of conjugating with nucleophilic compounds such as N-acetyl-cysteine (NAC) and glutathione (GSH) has been investigated in vitro. Three isomeric conjugates of 5-ASA and NAC as well as three isomeric conjugates of 5-ASA and GSH were found to be formed. 5-ASA was initially oxidized by PbO2 in a solution of TRIS-HCl buffer pH 9.3 followed by the in situ addition of N-acetyl-cysteine or glutathione to the oxidized 5-ASA at pH 7.5. The resulting conjugates were N-acetylated at the aromatic amino group in order to avoid autooxidation of the products formed. The N-acetylated conjugates were isolated by preparative HPLC and the structures were characterized by nuclear magnetic resonance (H-1-NMR and C-13-NMR) spectroscopy as well as by mass spectrometry (MS) and the data obtained confirmed the formation of thioether linkages between 5-ASA and the SH compounds. The chemical nature of the reactive intermediate capable of adding SH compounds was verified to be the 2-carboxy-quinone monoimine by H-1-NMR spectroscopy. The N-acetylated conjugates of 5-ASA and NAC were used as reference standards in order to investigate whether such conjugates are excreted in the urine from persons treated with 5-ASA. The N-acetyl-cysteine conjugates could be detected by fluorescense, which resulted in low detection limits ranging from 0.02 mug to 0.06 mug per ml corresponding to the transformation of about 0.003% of the daily dose of 5-ASA into mercapturic acids of 5-ASA, when 1 g of 5-ASA was ingested. In spite of the low detection limits, none of the mercapturic acid conjugates was detected in the urine from persons treated with 5-ASA.
AB - The ability of 5-aminosalicylic acid (5-ASA) to be oxidized to a quinone monoimine compound capable of conjugating with nucleophilic compounds such as N-acetyl-cysteine (NAC) and glutathione (GSH) has been investigated in vitro. Three isomeric conjugates of 5-ASA and NAC as well as three isomeric conjugates of 5-ASA and GSH were found to be formed. 5-ASA was initially oxidized by PbO2 in a solution of TRIS-HCl buffer pH 9.3 followed by the in situ addition of N-acetyl-cysteine or glutathione to the oxidized 5-ASA at pH 7.5. The resulting conjugates were N-acetylated at the aromatic amino group in order to avoid autooxidation of the products formed. The N-acetylated conjugates were isolated by preparative HPLC and the structures were characterized by nuclear magnetic resonance (H-1-NMR and C-13-NMR) spectroscopy as well as by mass spectrometry (MS) and the data obtained confirmed the formation of thioether linkages between 5-ASA and the SH compounds. The chemical nature of the reactive intermediate capable of adding SH compounds was verified to be the 2-carboxy-quinone monoimine by H-1-NMR spectroscopy. The N-acetylated conjugates of 5-ASA and NAC were used as reference standards in order to investigate whether such conjugates are excreted in the urine from persons treated with 5-ASA. The N-acetyl-cysteine conjugates could be detected by fluorescense, which resulted in low detection limits ranging from 0.02 mug to 0.06 mug per ml corresponding to the transformation of about 0.003% of the daily dose of 5-ASA into mercapturic acids of 5-ASA, when 1 g of 5-ASA was ingested. In spite of the low detection limits, none of the mercapturic acid conjugates was detected in the urine from persons treated with 5-ASA.
KW - 5-aminosalicylic acid oxidation 2-carboxy-1,4-benzoquinone monoimine n-acetyl-cysteine mercapturic acids of 5-aminosalicylic acid metabolites oxidation sulphasalazine acetaminophen mechanism products
M3 - Tidsskriftartikel
VL - 1
SP - 143
EP - 150
JO - Norvegica Pharmaceutica Acta
JF - Norvegica Pharmaceutica Acta
SN - 0928-0987
IS - 3
ER -
ID: 38061698