The Photoreactivity of Bilirubin and Related Pyrroles

Lightner, David A.

doi:10.1111/j.1751-1097.1977.tb07510.x

Cited by 78 publications

(31 citation statements)

References 91 publications

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“…The structures of the separated standard UCB photoox idation products were confirmed by comparison with prev iously reported reference standards (7,8) and by the ir 100 MHz IH NMR spectra obtained from a lEaL FX-100 instrument. A sample of the dipyrrole dialdehyde was provided by Dr. A. F. McDonagh, School of Medicine, University of California, San Francisco.…”

Section: Methodsmentioning

confidence: 87%

“…In early studies with Gunn rats, Ostrow (20) suggested that VCB was photo oxidized to smaller, more polar, water-soluble degradation products such as mono-and dipyrroles that were easily excreted. In support of that proposal, DCB photooxidation in vitro was examined, and many water-soluble photodegradation products were separated and characterized (7,8). There is no conclusive evidence supporting the occurrence ofDCB photooxidation in vivo during phototherapy, and no specific photooxidation products have been isolated and identified.…”

Section: Discussionmentioning

confidence: 99%

“…This important finding was extremely intriguing because VCB normally cannot be excreted by the liver unless it is converted to polar conjugates, principally glucuronides (2). To accommodate the confirmed (II , 21) biliary excretion, Z +Z E photochemical configurational isomerization at the mesocarbon-carbon double bonds of (4Z, 15Z)-biIirubin-IXa was proposed (7,8) to give more polar E-isomers, isomers that could more easily cross the liver. The hypothesis was subsequentl y tested (15) and confirmed in Gunn rats (12,24).…”

Section: Discussionmentioning

confidence: 99%

“…A sample of the dipyrrole dialdehyde was provided by Dr. A. F. McDonagh, School of Medicine, University of California, San Francisco. The eight reference standards (7,8) (shown in Fig. I) include: the dimethyl ester of the hydrolysis product of methylvinylmaleimide (HPLC peak a), the trimethyl ester of the hydrolysis product of hematinic acid (HPLC peak b), hematinic acid methyl ester (H PLC peak c), methylvinylmal-.…”

Section: Methodsmentioning

confidence: 99%

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Bilirubin Photooxidation Products in the Urine of Jaundiced Neonates Receiving Phototherapy

1984

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SummaryBilirubin-IXa photooxidation products were detected by high performance liquid chromatography in the urine of neonates undergoing phototherapy for hyperbilirubinemia. The in vivo photoproducts were identified by chromatographic comparison with authentic synthetic standards using two complementary methods. Bilirubin photooxidation products were not detected in urine from jaundiced infants not receiving phototherapy. The specific photoproducts identified in the urine include propentdyopents, hematinic acid imide and its hydrolysis product (3-carboxy-2-methyl-2-hexenedioic acid), and the hydrolysis product (2-vinyl-3-methyl-maleic acid) of methylvinylmaleimide. Their total urinary concentrations were low (0.2-0.9 mg/dl) during phototherapy. These observations show that photooxidation of bilirubin clearly does occur during phototherapy. They are consistent with the view that, although photooxidation is not the major photochemical event associated with phototherapy, it can and clearly does occur concurrently with photoisomerization.

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Section: Methodsmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Bilirubin Photooxidation Products in the Urine of Jaundiced Neonates Receiving Phototherapy

1984

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“…1) are likely predominant, as supported by chemical and spectroscopic evidence (9,16). Their formation precedes or accompanies other photoreactions of bilirubin, such as photo-oxidation (8), photo-addition of nucleophilic molecules to the 18-vinyl group (4,12,13), photoscrambling to IIIa and XIIa isomers (I), and production of certain poorly characterized yellow products, e.g., photobilirubin I1 (27), "430 pigment" (6), "41 5 pigment" (21), and "peak 1" (5). The configurational photoisomers of bilirubin, commonly known as photobilirubin (9), appear to be more polar, less lipophilic, and probably more acidic than the natural pigment (10).…”

mentioning

confidence: 87%