Absorption, excretion, and distribution of dietary antioxidant betalains in LDLs: potential health effects of betalains in humans.

Auteur(s) :
Tesoriere L., Allegra M., Butera D., Livrea MA.
Date :
Oct, 2004
Source(s) :
AMERICAN JOURNAL OF CLINICAL NUTRITION. #80:4 p941-945
Adresse :
Dipartimento Farmacochimico Tossicologico e Biologico, Universita di Palermo, Palermo, Italy.

Sommaire de l'article

BACKGROUND:
Betalains were recently identified as natural antioxidants. However, little is known about their bioavailability from dietary sources.

OBJECTIVE:
The objective was to evaluate the bioavailability of betalains from dietary sources.

DESIGN:
The plasma kinetics and urinary excretion of betalains were studied in healthy volunteers (n = 8) after a single ingestion of 500 g cactus pear fruit pulp, which provided 28 and 16 mg indicaxanthin and betanin, respectively. The incorporation of betalains in LDL and the resistance of the particles to ex vivo-induced oxidation was also researched.

RESULTS:
Betanin and indicaxanthin reached their maximum plasma concentrations 3 h after the fruit meal and declined according to first-order kinetics. The half-life of betanin (0.94 +/- 0.07 h) was shorter than that of indicaxanthin (2.36 +/- 0.17 h). Both compounds had disappeared from plasma by 12 h after intake. The urinary excretion of indicaxanthin and betanin over 12 h represented 76 +/- 3.0% and 3.7 +/- 0.2%, respectively, of the ingested compounds. LDL isolated 3 and 5 h after the fruit meal incorporated betalains at concentrations of 100.5 +/- 11 and 50 +/- 7.2 pmol/mg LDL protein, respectively. In addition, the particles appeared more resistant to ex vivo-induced oxidative injury than did the samples isolated before fruit ingestion (P < 0.05)-the higher the amount of betalains incorporated, the higher the resistance. The concentrations of vitamin E and beta-carotene in LDL did not change significantly after fruit ingestion.

CONCLUSION:
Our results show that cactus pear fruit is a source of bioavailable betalains and suggest that indicaxanthin and betanin may be involved in the observed protection of LDL against ex vivo-induced oxidative modifications.

Source : Pubmed
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