A purgative action of barbaloin is induced by Eubacterium sp. strain BAR, a human intestinal anaerobe, capable of transforming barbaloin to aloe-emodin anthrone.
Orally administered barbaloin (100 mg/kg) did not induce any diarrhea in male Wistar rats, in spite of severe diarrhea with sennoside B (40 mg/kg). Also, in gnotobiote rats mono-associated with Peptostreptococcus intermedius, a human intestinal anaerobe capable of reducing sennidins to rhein anthrone, barbaloin did not induce diarrhea; the faecal water content (71.9%) 8 h after the administration of barbaloin was not increased, compared with that (73.9%) just before the treatment. However, severe diarrhea was induced with barbaloin in gnotobiote rats mono-associated with Eubacterium sp. strain BAR, another human intestinal anaerobe capable of transforming barbaloin to aloe-emodin anthrone; the faecal water content was significantly increased to 85.5% 8 h after the administration, from 73.2% before the treatment. At this time, barbaloin was transformed to aloe-emodin anthrone in the feces from the gnotobiote rats mono-associated with the strain BAR, but not in feces from the conventional rats or the gnotobiote rats mono-associated with P. intermedius. These facts indicate that barbaloin is inactive as a laxative itself but is activated to aloe-emodin anthrone, a genuine purgative component, by Eubacterium sp. strain BAR.
Akao
T
T
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Che
Q M
QM
Kobashi
K
K
Hattori
M
M
Namba
T
T
D000818:Animals; D000873:Anthracenes / Q000378:metabolism / Q000494:pharmacology*; D000880:Anthraquinones; D002400:Cathartics / Q000378:metabolism / Q000494:pharmacology*; D003470:Culture Media; D003967:Diarrhea / Q000139:chemically induced; D004642:Emodin / Q000494:pharmacology*; D005051:Eubacterium / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D007422:Intestines / Q000382:microbiology* / Q000502:physiology; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D000873:Anthracenes; D000880:Anthraquinones; D002400:Cathartics; D003470:Culture Media; C045601:barbaloin; C518327:aloe emodin; D004642:Emodin