Rhein
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| Compound | Rhein |
| Animal species | human intestinal bacteria Bacteroides spp. RHEIN-I and RHEIN-II |
| Metabolism parameters | |
| Metabolites |
Rhein
Rhein anthrone |
| Crude drug | Rhubarb |
| References | 1) Meselhy M. R., Nishimoto E., Akao T. and Hattori M.: Human intestinal Bacteroides spp. RHEIN-I and RHEIN-II capable of transforming rhein to rheinanthrone, induce rhein-dependent diarrhea in rats. J. Trad. Med., 18, 169-176 (2001). |
| Remarks | ※Preparation of an intestinal bacteria mixture and determination of anthrone A fresh stool sample (1 g) obtained from a healthy man was suspended in 5 ml of 50 mM K-phosphate buffer, pH 7.3. The suspension was filtered with a piece of gauze and made up to 100 ml with the same buffer. This suspension was used as an intestinal bacterial mixture. For quantitative determination of rhein anthrone , N, N'-dimethyl-p-nitrosoaniline (DMPA) in pyridine were added to the culture and mixed. The mixture was then extracted with butanol saturated with H2O (200 μl). Five microlitres of the BuOH layer were applied to a TLC plate, which was developed with CHCl3-MeOH (7:3). Rhein-metabolizing activity was monitored visually by observing a bluish-green spot (R/ 0.6). [Meselhy et al., J. Trad. Med., 18, 169-176 (2001)] ※Suspensions (500//l) of B. sp. RHEIN-I and RHEIN-II were separately added to GAM broth (100 ml) and incubated for 24 hr under anaerobic conditions. Individual cultures were centrifuged at 1500 x g for 15 min and the pellets were washed with 50 mM K-phosphate buffer (pH 7.3, 15 ml), and re-suspended in the same buffer (2 ml). Rhein (in 1% NaHCO3 solution) was separately added to each bacterial suspension to give 4.9 μmol/ml of the compound, and the mixture was incubated under anaerobic conditions. A portion (200//l) of the culture was taken out at intervals and rhein anthrone was determined as an azomethine derivative by TLC-densitometry at a wavelength of 660 nm relative to a reference wavelength of 780 nm, using a calibration line of an authentic azomethine derivative of rheinanthrone. The calibration line was linear in a range of 2.48-20 nmol/spot. [Meselhy et al., J. Trad. Med., 18, 169-176 (2001)] |
