Metabolic profile and underlying improved bio-activity of Fructus aurantii immaturus by human intestinal bacteria
Fructus aurantii immaturus (FAI) is the dried young fruit of Cirtus aurantium L.or Citrus sinensis. L. Osbeck. The purpose of this paper was to investigate the metabolic fate of FAI by the human intestinal bacteria, meanwhile to evaluate the antioxidant and anti-inflammatory activities of FAI and the transformed Fructus aurantii immaturus (TFAI). The water extract of FAI was anaerobically incubated with human intestinal bacteria suspensions for 48 h at 37 °C. A liquid chromatography-hybrid quadrupoletime-of-flight mass spectrometry (LC-Q-TOF/MS) was applied to identify FAI metabolites. A total of 45 compounds in FAI were identified, eleven of which were metabolized by human intestinal bacteria. And nine major metabolites were identified as eriodictyol, naringenin, hesperetin, luteolin, apigenin, chryseriol, isosakuranetin, phloretin and diosmetin. The metabolic profile of FAI was elucidated on the basis of the metabolite information. We found that concentrations of acetic, propionic and butyric acids in FAI culture all were increased during the fermentation relative to those of the control. Further bioactive evaluations showed that TFAI exhibited more potent antioxidant and anti-inflammatory ability than FAI in vitro. Additionally, in vivo experiment confirmed that FAI significantly attenuated the blood endotoxin and TNF-α levels in the conventional rats compared with that of pseudo germ-free (PGF) rats. This study revealed that metabolites may play a key role in the antioxidant and anti-inflammatory capacities of FAI.