Characterization of metabolites of sweroside in rat urine using ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry and NMR spectroscopy

Abstract

Sweroside, a major active iridoid in Swertia pseudochinensis Hara, is recognized as an effective agent in the treatment of liver injury. Based on previous reports, the relatively short half-life (64 min) and poor bioavailability (approximately 0.31%) in rats suggested that not only sweroside itself but also its metabolites could be responsible for the observed hepato-protective effect. However, few studies have been carried out on the metabolism of sweroside. Therefore, the present study aimed at identifying the metabolites of sweroside in rat urine after a single oral dose (100 mg/kg). With ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS), the metabolic profile revealed 11 metabolites in rat urine, including phase I, phase II and aglycone-related products. The chemical structures of metabolites were proposed based on accurate mass measurements of protonated or deprotonated molecules and their fragmentation patterns. Our findings showed that the aglycone of sweroside (M05) and its glucuronide conjugate (M06) were principal circulating metabolites in rats. While several other metabolic transformations, occurring via reduction, N-heterocyclization and N-acetylation after deglycosylation, were also observed. Two metabolites (M05 and M06) were isolated from the rat urine for structural elucidation and identifcation of reaction sites. Both M05 and M06 were characterized by (1)H, (13)C and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. UHPLC/Q-TOF-MS analysis has provided an important analytical platform to gather metabolic profile of sweroside.

Chemical fingerprint and bioactivity evaluation of Globularia orientalis L. and Globularia trichosantha Fisch. & C. A. Mey. using non‐targeted HPLC‐ESI‐QTOF‐MS approach

“…Compound with RT 15.16 min ( m / z 357) was only found in G. orientalis , and it was tentatively identified as sweroside. Its fragment at m / z 195 was related to a deglycosylation of sweroside while the fragment at m / z 177 was formed by the loss of a carbonyl group from [aglycone – H] − . Peak 37 presented MS fragment at m / z 161 and 269 and had been previously described in other plant matrices .…”

Sweroside Prevents Non-Alcoholic Steatohepatitis by Suppressing Activation of the NLRP3 Inflammasome

“…Sweroside is known to possess a wide variety of biological activities, including wound healing, as well as anti-bacterial, anti-fungal, and anti-allergic effects, and is typically considered in the treatment of hepatobiliary disorders [12]. Pre-clinical experiments in rats have shown that the administration of sweroside effectively protects against chemical-induced liver fibrosis and injury [13,14].…”

Biotransformation and metabolic profile of Xian‐Ling‐Gu‐Bao capsule, a traditional Chinese medicine prescription, with rat intestinal microflora by ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry analysis

“…The aglycone of sweroside was generated by deglycosylation ( I‐M3 ), which was probability generated in a dialdehyde form. The two carbonyl carbons of the dialdehyde the equivalent probability of being nucleophilically attacked by ammonia to form a Schiff base, which was subjected to intramolecular cyclization to give the pyridine monoterpene alkaloidtype metabolites (Han et al, ). According to the 1‐octanol–water partition coefficient, the structures of I‐M5 ( C log P = −0.82) and I‐M6 ( C log P = −0.70) were tentatively identified as in Table .…”