The differential tissue distribution of the citrus flavanone naringenin following gastric instillation.
Citrus flavonoids have been investigated for their biological activity, with both anti-inflammatory and -carcinogenic effects being reported. However, little information is known on the bioavailability of these compounds in vivo. The objectives of this study were to determine the tissue distribution of naringenin after gastric gavage of [3H]-naringenin to rats. Unlabelled naringenin was also used to quantify the levels of naringenin and its major metabolites in tissues and eliminated in the urine and faeces. Significant radioactivity was detected in the plasma as well as all tissues examined 2h post-gavage. After 18h, higher levels of radioactivity were retained in plasma and tissues (55% of the administered radioactivity). Investigation of the nature of metabolites, using unlabelled naringenin, revealed that the glucuronides were the major components in plasma, tissues and urine, in addition to the colonic metabolite 3-(4-hydroxyphenyl) propionic acid, detected in the urine. The aglycone was the form extensively retained in tissues after 18h post-gavage. Total identified metabolites detected after 18h in most tissues were only 1-5% of the levels detected after 2h. However, the brain, lungs and heart retained 27, 20 and 11%, respectively, relative to the total metabolites detected at 2h. While radioactive detection suggests increased levels of breakdown products of naringenin after 18 h versus 2 h, the products identified using unlabelled naringenin are not consistent with this, suggesting that a predominant proportion of the naringenin breakdown products at 18 h are retained as smaller decomposition molecules which cannot yet be identified.
El Mohsen
Manal Abd
MA
Antioxidant Research Group, Wolfson Centre for Age-Related Diseases, GKT School of Biomedical Sciences, King's College, London, SE1 9RT UK.
Marks
Joanne
J
Kuhnle
Gunter
G
Rice-Evans
Catherine
C
Moore
Kevin
K
Gibson
Glenn
G
Debnam
Edward
E
Srai
S Kaila
SK
D000818:Animals; D001682:Biological Availability; D002957:Citrus / Q000737:chemistry; D044950:Flavanones / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D007322:Instillation, Drug; D008297:Male; D013058:Mass Spectrometry; D051381:Rats; D013270:Stomach; D014018:Tissue Distribution
D044950:Flavanones; C005273:naringenin