Biotransformation of Glucoraphenin by Rat Intestinal Flora and the Effect of Promoting Intestinal Motility in Zebrafish

Abstract

Glucoraphenin (GRE), a glucosinolate in Raphanus sativus L. seeds and roots, can degrade into isothiocyanates through myrosinase. However, myrosinase in R. sativus roots and seeds is inactivated during cooking, allowing GRE to enter the body in its unmodified form and exert bioactivity. Therefore, investigating the biotransformation of GRE by intestinal flora and the activity of GRE and its metabolites is essential. In this study, fresh fecal samples from healthy Sprague-Dawley rats were collected to prepare an intestinal flora culture medium, which was incubated with GRE under anaerobic conditions. GRE metabolite was isolated through Sephadex LH-20 column chromatography, and the structure was identified using high-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF/MS) and nuclear magnetic resonance (NMR). Additionally, fluorescence labeling and the number of intestinal peristalses were employed to assess the effect of GRE and its metabolite on intestinal motility in zebrafish models. Results indicated that GRE can be metabolized in vitro by rat intestinal flora, producing glucoraphasatin (GRH). NMR and MS analysis confirmed GRH's structure as 4-methylthio-3-butenyl glucosinolate. Both GRE and GRH were found to enhance intestinal peristalsis in zebrafish. This study elucidates GRE's metabolic pathway in the intestinal flora and suggests that GRE and GRH may be functional components to promote intestinal motility.