Study on chemical profiles and metabolites of Allii Macrostemonis Bulbus as well as its representative steroidal saponins in rats by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.

Allii Macrostemonis Bulbus (AMB) is increasingly becoming popular as an edible vegetable or traditional folk medicine in East Asia due to its great health and medicinal properties. However, due to a lack of available research, the effective material of AMB still remains unknown. In this study, we applied a strategy utilising ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) to investigate chemical profiles of AMB. In addition, metabolite profiles of five representative single steroidal saponins as well as AMB were investigated. Moreover, the metabolic features of saponins in AMB were summarised. After oral administration, the saponins underwent massive phase I and phase II metabolism. Sequential deglycosylation metabolism in rat intestine was the main metabolic pathway of the steroidal saponins, while oxidation, dehydrogenation, glucuronic acid reactions in liver also take part in further modification. These results expand our knowledge about the metabolism of AMB.

[Immunization with catalase and UreB two-valence vaccine for preventing Helicobacter pylori infection in mice].

OBJECTIVE: To investigate the effects of the two-valence vaccine consisting of Helicobacter pylori (H. pylori) catalase and urease subunit UreB in preventing H. pyloriinfection in mice. METHODS: C57BL/6 mice were divided into 7 groups and immunized with intragastric administration of catalase and UreB (both 100 microg) plus cholera toxin (CT, 2 microg), catalase (100 microg) plus CT (2 microg), UreB (100 microg) plus CT (2 microg), catalase (100 microg), UreB (100 microg), CT (2 microg), or PBS, respectively, once a week for 4 consecutive weeks. Two weeks after the last immunization, all the mice were challenged by live H. pylori, and sacrificed 4 weeks after the challenge to obtain the gastric mucosa samples for detecting H. pylori using semi-quantitative bacterial culture assay. RESULTS: The total protection rate in mice immunized with the two-valence vaccine, single-valence vaccine of catalase, and single-valence vaccine of UreB was 83.3% (20/24), 41.7% (10/24) and 54.2% (13/24), respectively, and the rate in the other 4 groups were all 0. The H. pyloricolony density in mice with vaccination was significantly lower than that of other 4 groups (P<0.05). The total protection rate and H. pylori colony density differed significantly between the two-valence vaccination group and the single-valence vaccination groups (P<0.05). CONCLUSION: The two-valence vaccine consisting of catalase, UreB and adjuvant has better immunoprotective effects than the single-valence vaccines.