Metabolism of aloesin and related compounds by human intestinal bacteria: a bacterial cleavage of the C-glucosyl bond and the subsequent reduction of the acetonyl side chain.
By anaerobic incubation with a bacterial mixture from human feces, aloesin (aloeresin B; 1) was converted to 2-acetonyl-7-hydroxy-5-methylchromone (aloesone; 3) and dl-7-hydroxy-2-(2'-hydroxypropyl)-5-methylchromone (aloesol; 4a + 4b) through a cleavage of the C-glucosyl bond, followed by reduction of the acetonyl side chain. An analogous compound, aloeresin A (2), was converted to p-coumaric acid and aloesin (1), the latter being subsequently transformed to aloesone (3) and dl-aloesol (4a + 4b). On the other hand, 7-O-methylated derivatives (7, 5a and 5b) of aloesin and of 8-C-glucosylaloesol were not cleaved to the corresponding aglycones, suggesting the importance of a free hydroxy group adjacent to the C-glucosyl group in the molecule for the bacterial cleavage of aloesin derivatives. This is the first report on the cleavage of the C-glycosyl bond of chromone C-glucosides by intestinal bacteria.
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QM
Research Institute for Wakan-Yaku Traditional Sino-Japanese Medicines, Toyama Medical and Pharmaceutical University, Japan.
Akao
T
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Hattori
M
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Kobashi
K
K
Namba
T
T
D000096:Acetone / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D002867:Chromones / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism*; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D010084:Oxidation-Reduction
D002867:Chromones; D005960:Glucosides; D000096:Acetone; D005947:Glucose; C069868:aloesin