Alteration in the number and composition of intestinal microbiota affects the metabolism of several xenobiotics. Gastrodin, isolated from Gastrodia elata, is prone to be hydrolyzed by intestinal microbiota. In the present study, the role of intestinal microbiota in gastrodin metabolism was investigated in vitro and in vivo. Gastrodin was incubated in an anaerobic condition with intestinal contents prepared from vehicle- and antibiotics-treated rats and the disappearance of gastrodin and formation of 4-hydroxybenzyl alcohol (4-HBA) was measured by liquid chromatography coupled to mass spectroscopy (LC-MS/MS). The results showed that almost all gastrodin incubated with control intestinal contents was metabolized to its aglycone in time- and concentration-dependent manners. In contrast, much less formation of 4-HBA was detected in intestinal contents from antibiotics-treated rats. Subsequently, in vivo pharmacokinetic study revealed that the antibiotic pretreatment of rats significantly affected the metabolism of gastrodin to 4-HBA. When administered orally, gastrodin was rapidly absorbed rapidly into plasma, metabolized to 4-HBA, and disappeared from the body within six hours. Interestingly, the pharmacokinetic parameters of 4-HBA were changed remarkably in antibiotics-treated rats, compared to control rats. The results clearly indicated that the antibiotics treatment of rats suppressed the ability of intestinal microbiota to metabolize gastrodin to 4-HBA and that, thereby, the pharmacodynamic action was significantly modulated.
Background
Voglibose, an α-glucosidase inhibitor, inhibits breakdown of complex carbohydrates into simple sugar units in intestine. Studies showed that voglibose metabolism in the liver might be negligible due to its poor intestinal absorption. Numerous microorganisms live in intestine and have several roles in metabolism and detoxification of various xenobiotics. Due to the limited information, the possible metabolism of voglibose by intestinal microbiota was investigated
in vitro
and
in vivo
.
Methods
For the
in vitro
study, different concentrations of voglibose were incubated with intestinal contents, prepared from both vehicle- and antibiotics-treated mice, to determine the decreased amount of voglibose over time by using liquid chromatography-mass spectrometry. Similarly,
in vivo
pharmacodynamic effect of voglibose was determined following the administration of voglibose and starch in vehicle- and antibiotic-pretreated non-diabetic and diabetic mice, by measuring the modulatory effects of voglibose on blood glucose levels.
Results
The
in vitro
results indicated that the remaining voglibose could be significantly decreased when incubated with the intestinal contents from normal mice compared to those from antibiotic-treated mice, which had less enzyme activities. The
in vivo
results showed that the antibiotic pretreatment resulted in reduced metabolism of voglibose. This significantly lowered blood glucose levels in antibiotic-pretreated mice compared to the control animals.
Conclusion
The present results indicate that voglibose would be metabolized by the intestinal microbiota, and that this metabolism might be pharmacodynamically critical in lowering blood glucose levels in mice.
The objective of this study was to evaluate quality characteristics of
low-nitrite emulsified-sausages (ESs, < 75 ppm) containing paprika
oleoresin solution (POS) for replacing sodium nitrite (NaNO
2
). Pork
ESs were prepared with four treatments (reference (REF), 150 ppm
NaNO
2
; TRT1, 0 ppm NaNO
2
+ 0.1% POS; TRT2, 37.5 ppm
NaNO
2
+ 0.1% POS; and TRT3, 75 ppm NaNO
2
+ 0.1% POS).
The physicochemical and texture properties, microbial counts, residual nitrite
and thiobarbituric acid reactant substances (TBARS) were measured during
refrigerated storage of 35 days. Although TRT2 and TRT3 had lower levels of
NaNO
2
, they had higher redness and yellowness than REF
(
p
< 0.05). Microbial counts of total bacterial
counts and
Enterobacteriaceae
of TRT2 and TRT3 were similar to
those of REF (
p
> 0.05). Expressible moisture
percentages (EM, %) of TRT2 and TRT3 were lower than those of REF
(
p
< 0.05). TBARS values of TRT2 and TRT3 were not
different from those of REF (
p
> 0.05). Among
treatments, TRT1 had the highest TBARS values (
p
<
0.05). In conclusion, 0.1% POS in combination with 37.5 ppm NaNO
2
would have quality characteristics similar to those of REF. Therefore,
approximately 3/4 of the initial nitrite level could be replaced with 0.1% POS,
and eventually developed healthier pork products.
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