The phenolic acids from bacterial degradation of the mangiferin aglycone are quantified in the feces of pigs after oral ingestion of an extract of Cyclopia genistoides (honeybush tea)
2010
Bock, Constance | Ternes, Waldemar
Polyphenols are cleaved by bacterial enzymes to form phenolic acid metabolites in the colon, where they may exert physiologic effects. For norathyriol, the aglycone of mangiferin, one of the major phenolic compounds present in Cyclopia genistoides (honeybush), a further bacterial degradation is likely; but knowledge of the importance of this metabolic process is very limited. Based on a hypothesized cleavage of the middle ring of norathyriol, this study was designed to determine phenolic cleavage products in the feces of pigs fed an extract of C genistoides. Pigs received 74 mg mangiferin per kilogram of body weight daily for 11 days; feces fractions were collected on day 11 and on the first 2 days after the last intake of extract. Several phenolic acids were detected in the feces samples, including 3-hydroxyphenylacetic acid; 4-hydroxybenzoic acid; 3,4-dihydroxybenzoic acid; 3,4-dihydroxyphenylacetic acid; 2,4,6-trihydroxybenzoic acid; 3,4,5-trihydroxybenzoic acid (gallic acid); and phloroglucinol. However, in vivo formation was likely only for 3,4-dihydroxybenzoic acid; 3,4-dihydroxyphenylacetic acid; 2,4,6-trihydroxybenzoic acid; and 3,4,5-trihydroxybenzoic acid because these were not present in the blank feces, in the animals' normal diet, or in the C genistoides extract. The fact that these amounts were very low suggests further degradation of the metabolites by intestinal microflora or absorption of the cleavage products by the colon.
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