Absorption characteristics of ilexgenin A and ilexsaponin B1 in human umbilical vein endothelial cells after administration of the total triterpenoid saponin from Ilex Pubescens

Six undescribed 23-norursane triterpenoids from the biotransformation of ilexgenin a by endophytic fungi and their vascular protective activity

Biotransformation of ursane-type triterpenoid ilexgenin A by endophytic fungi Lasiodiplodia sp. MQD-4 and Pestalotiopsis sp. ZZ-1, isolated from Ilex pubescences and Callicarpa kwangtungensis respectively, was investigated for the first time. Six previously undescribed metabolites (1-6) with 23-norursane triterpenoids skeleton were isolated and their structures were unambiguously established by the analysis of spectroscopic data and single-crystal X-ray crystallographic experiments. Decarboxylation, oxidation, and hydroxylation reactions were observed on the triterpenoid skeleton. Especially, the decarboxylation of C-23 provided definite evidence to understand the biogenetic process of 23-norursane triterpenoids. Moreover, the qualitative analysis of the extract of I. pubescences showed metabolites 1, 3, 4, and 6 could be detected in the originated plant, indicating biotransformation by endophytic fungi is a practical strategy for the isolation of novel natural products. Finally, all isolates were evaluated for the protective activities against H2O2-induced HUVECs dysfunction in vitro. Compound 5 could improve the viability of endothelial cells and decrease the level of intracellular ROS.

Chemical components with biological activities in the roots of Ilex pubescens

Two new triterpenoids, ilexsaponin U (1) and ilexsaponin V (2), and three new phenylpropanoids, pubescenoside S (3), pubescenoside T (38), and pubescenoside U (39), along with thirty-four existing compounds were isolated from the roots of Ilex pubescens. The elucidation of their structures involved comprehensive spectroscopic techniques, including IR, UV, HR-ESI-MS, and NMR experiments. The anti-inflammatory effects of almost all the compounds were evaluated in LPS-induced RAW264.7 cells. Among these, compounds 1, 4, 8, 11, 12, 26, 27, 29 and 33 exhibited varying degrees of inhibition of inflammatory factors. Notably, compounds 1, 4 and 8 significantly inhibited the mRNA levels of iNOS, IL-6, IL-1β and TNFα, comparable to or exceeding the effect of the positive control (dexamethasone, DEX). We also evaluated the cardioprotective effects of these compounds in OGD/R-induced H9c2 cells. The results revealed that compounds 2, 3, 7, 8, 26, 35, 36 and 37 at 20 μM significantly increased cell viability by 24.9 ± 3.4%, 28.0 ± 0.3%, 37.6 ± 0.2%, 44.86 ± 0.5%, 9.47 ± 2.1%, 23.9 ± 0.4%, 39.5 ± 3.1% and 28.2 ± 0.1%, respectively. Some of them exhibited effects equal to or greater than that of the positive control (diazoxide, DZ) at 100 μM, showing a 21.9 ± 3.0% increase.

UPLC-Q-TOF/MS based metabolite profiling and quality marker constituents screening of root, stem and rhizome extracts of Ilex asprella

OBJECTIVE

The root of Ilex asprella (RIA) is a popular plant resource for treating inflammation-related diseases. The purpose of this study was to identify the secondary metabolites, to compare anti-inflammatory effects and to determine the quality marker components among root, stem and rhizome sections of IA.

METHODS

Chemical fingerprints of stem, root and rhizome of IA was determined by high performance liquid chromatography (HPLC). A reliable method using ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was established for comprehensively determining the chemical constituents of the plants. Anti-inflammatory activities of IA and its ingredients were screened by in vivo mouse ear swelling and in vitro LPS-induced release of NO from RAW264.7 cells experiments.

RESULTS

Root, stem and rhizome of IA have shown high similarity in chemical fingerprints. Totally 149 compounds were characterized in IA, including triterpenoids, triterpenoid saponins, phenolic acids and lignans. 44 of them were identified based on co-occurring Mass2Motifs, including 19 unreported ones, whilst 17 were tentatively confirmed by comparison with reference compounds. No significant anti-inflammatory activity difference among root, stem and rhizome parts of IA was found. Ilexsaponin B2, protocatechualdehyde, isochlorogenic acid B and quinic acid, were screened out as quality marker compounds in IA.

CONCLUSION

A sensitive and rapid strategy was established to evaluate the differences on secondary metabolites of different parts of IA for the first time, and this study may contribute to the quality evaluation of medicinal herbs and provide theoretically data support for further analysis of different parts of IA.

Pharmacokinetic and tissue distribution study of six saponins in the rat after oral administration of Ilex pubescens extract using a validated simultaneous UPLC-qTOF-MS/MS assay

Ilex pubescens Hook. et Arn is a medicinal plant of the Ilex family that is mainly used for the treatment of cardiovascular diseases. Its main medicinal ingredients are total triterpenoid saponins (IPTS). However, the pharmacokinetics and tissue distribution of the main multi-triterpenoid saponins are lacking. This is the first report that demonstrates a sensitive ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-qTOF-MS/MS) method for the quantification of ilexgenin A (C1), ilexsaponin A1 (C2), ilexsaponin B1 (C3), ilexsaponin B2 (C4), ilexsaponin B3 (DC1) and ilexoside O (DC2) in rat plasma and various tissues of the heart, liver, spleen, lungs, kidney, brain, stomach, duodenum, jejunum, ileum, colon and thoracic aorta. The chromatographic separation was carried out on an Acquity HSS T3 UPLC column (2.1 × 100 mm, 1.8 µm, Waters, USA) with a mobile phase consisting of 0.1% (v/v) formic acid (A) and acetonitrile containing 0.1% (v/v) formic acid (B) at a flow rate of 0.25 mL/min. The MS/MS detection was performed by electrospray ionization (ESI) using selected ion monitoring (SIM) in negative scan mode. The developed quantification method showed good linearity over the concentration range of 10-2000 ng/mL for plasma and 25-5000 ng/mL for tissue homogenates with R² ≥ 0.990. Lower limits of quantification (LLOQ) was 10 ng/mL in plasma and 25 ng/mL in tissue homogenates. The intra- and inter-day precision were less than 10.39%, and the accuracy was between - 1.03% and 9.13%. The extract recoveries, dilution integrity and matrix effect were well within satisfactory limits. Using the validated method, the pharmacokinetic parameters, including half-life, AUC, Cmax, CL, and MRT, of six triterpenoid saponins in rats after oral administration were provided by establishing their plasma concentration-time curves, while their absolute quantification in various tissues after oral administration was also determined at first, which provides a scientific basis for their clinical application.

Triterpenoid saponins of Ilex pubescens against TNF-α induced inflammation and apoptosis in human umbilical vein endothelial cells via autophagy pathway

OBJECTIVES

Triterpenoid saponins of Ilex pubescens (IPTS), the main active components of Ilex pubescens, has a therapeutic effect on atherosclerosis (AS). The ingredients in IPTS that could be intracellularly transported by human umbilical vein endothelial cells (HUVECs) may play an essential role in AS. This study attempted to explore its mechanism from the perspectives of HUVECs' inflammation, apoptosis, and autophagy.

METHODS

By using a tumour necrosis factor-α (TNF-α)-induced HUVECs injury model, cell viability and the expression of intercellular adhesion molecule 1 (ICAM1), matrix metalloproteinase 9 (MMP9), cleave-caspase-3 and cleave-caspase-9, in combination with the results of flow cytometry, JC-1 and Hoechst 33258 staining were investigated to evaluate the anti-inflammatory and anti-apoptotic impact effects of IPTS on HUVECs. Afterwards, the expression of microtubule-associated proteins light chain 3II (LC3II) and sequestosome 1 (p62) was determined to test the effect of IPTS on autophagy. Finally, by adding an autophagy inhibitor 3-methyladenine (3-MA), we investigated whether IPTS exerts anti-inflammatory and anti-apoptotic effects through the autophagy pathway.

KEY FINDINGS

We firstly demonstrated that pretreatment with IPTS could increase the cell viability, maintain the cell morphology and reduce TNF-α-induced inflammation and apoptosis of HUVECs. Moreover, IPTS pretreatment was proved to raise the expression of LC3II /LC3I while decreasing the expression of p62, which indicated that IPTS could activate HUVECs' autophagy. IPTS has been shown for the first time to exert anti-inflammatory and anti-apoptotic effects through autophagy and thereby resisting TNF-α-induced inflammatory injury of HUVECs.

CONCLUSIONS

This study preliminarily confirmed that IPTS ameliorated HUVECs' inflammation and apoptosis by increasing autophagy.