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The metabolism and fate of [methyl‐ 14 C] and [uronate‐6‐ 14 C]pectin‐labelled dietary plant cell walls in the rat
Author(s) -
Buchanan Callum J,
Fry Stephen C,
Eastwood Martin A
Publication year - 1994
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740660209
Subject(s) - pectin , cell wall , chemistry , metabolism , biochemistry , methionine , spinach , glucuronic acid , fatty acid , alanine , polysaccharide , amino acid
The metabolism of dietary plant cell walls (PCW) was followed in the rat using PCW isolated from spinach cell cultures which were 14 C‐labelled in the galacturonic acid residues (using D‐[6‐ 14 C]glucuronic acid, ⩾85% of the 14 C was confined to the C‐6 position of pectic galacturonic acid residues) or the methyl ester groups (using L‐[methyl‐ 14 C]methionine, 90% of the 14 C was confined to methyl ester groups and 10% of the 14 C in methyl ether groups) of pectin. Eighteen hours after gavage, only 5‐10% of the 14 C was recovered in the gut contents and faeces. Some of the 14 C derived from the [methyl‐ 14 C]pectin‐labelled PCW was present in the liver (2‐4%) and the pelt (6%). In the liver the 14 C was mainly in phospholipids, whereas in the pelt the 14 C was found in protein (mainly alanine residues) and fatty acids esterified to cholesterol. The livers from rats fed [uronate‐6‐ 14 C]pectin‐labelled PCW contained less 14 C (1%) but more 14 C was found in the pelt (12‐15%). In the liver the 14 C was found in phospholipid but in the pelt the label was exclusively found in amino acid residues. Pectin in intact PCW is extensively degraded in the caecum and colon and the products absorbed and metabolised by the host. These products may be important sources of energy and of precursors of structural compounds such as proteins and lipids.