Characterization of Metabolic Pathways and Absorption of Sea Cucumber Saponins, Holothurin A and Echinoside A, in Vitro and in Vivo

Abstract

Sea cucumber saponins (SCSs) exhibit a wide spectrum of bioactivities, but their metabolic characteristics are not well elucidated. In this study, the metabolism of holothurin A (HA) and echinoside A (EA), 2 major saponins in sea cucumber, by gut microflora were investigated. First, we conducted an in vitro study, where in the SCSs were incubated with intestinal microflora and the metabolites were detected by high pressure liquid chromatography-high resolution mass spectrometry. We also conducted an in vivo study on rats, where in the intestinal contents, serum, urine, and feces were collected and evaluated after oral administration of SCSs. In the in vitro study, we identified 6 deglycosylated metabolites of HA and EA, assigned M1-M6. In the in vivo study, we found all the deglycosylated metabolites in the intestinal contents after oral administration, and both the metabolites and their prototype components could be absorbed. Four metabolites were identified in the serum, 6 in the urine, and 4 in the feces. The saponins with different structures showed different absorption characteristics in rats. According to our results, deglycosylation is the main intestinal microflora-mediated metabolic pathway for SCSs, and both the SCSs and deglycosylated metabolites can be absorbed by intestine. This study improves the understanding of the metabolism of HA and EA by gut flora, which will be useful for further analysis of the bioactivity mechanism of SCSs.

Characterization and Absorption Kinetics of a Novel Multifunctional Nanoliposome Stabilized by Sea Cucumber Saponins Instead of Cholesterol

“…Meanwhile, all three deglycosylated metabolites of HA were detected in the serum, and the peak contents were 0.4, 0.2, and 0.3 μg/mL, respectively, which was only 0.67–1.33% of HA. Only one of the three metabolites of EA (E1) was detected with a peak of 0.04 μg/mL in the serum of rats, while the peak of EA in the serum was 1.8 μg/mL . It could be proved that the deglycosylated metabolites of EA and HA could have existed in the serum after oral administration of the SCSs.…”

“…The LC–MS/MS system was used to determine HA, EA, and metabolites in the serum, liver, and small intestinal contents . Chromatographic separations were achieved on an Agilent 1260 HPLC separation system (Palo Alto, CA, USA) using a Proshell 120 EC-C18 (3.0 mm × 150 mm, 2.7 μm).…”

“…The LC−MS/MS system was used to determine HA, EA, and metabolites in the serum, liver, and small intestinal contents. 40 Statistical Analysis. All experimental samples were in triplicate, and the results were expressed as mean ± standard deviation.…”

Marine natural products

“…715 Metabolism of triterpenoids holothurin A and echinoside A, both by incubation with gut microora (in vitro) or in vivo in rats, identied deglycosylation to be the dominant process. 716 The proles of triterpenoid glycosides in ve different body components (respiratory trees, body walls, gonad tubules, guts, and aquapharyngeal bulbs) of the sea cucumber Eupentacta fraudatrix were found to be qualitatively similar but with some variability in minor compounds. 717 Transcriptome sequence data for three brittle star species (Ophionotus victoriae, Amphiura liformis, Ophiopsila aranea) identied a number of neuropeptide precursor proteins.…”

<p>Beneficial Effects of Echinacoside on Diabetic Cardiomyopathy in Diabetic <em>Db/Db</em> Mice</p>

“…The active chemical of ECH is phenylethanoside, which displays antioxidant, anti-fatigue, anti-tumor and anti-inflammatory effects, and can improve memory, nerve and liver protection, and enhance immune regulation. 16,17 In the study on db/db diabetic mice, it was found that ECH could improve insulin resistance, increase HDL level, and reduce TG, TC and LDL levels, indicating that ECH could effectively improve diabetic lipid metabolism. 18 In addition, Shimoda et al proved that echinoside could affect lipid metabolism by regulating mRNA related to hepatobiliary sterol transport and metabolism.…”