Alismatis Rhizoma methanolic extract—Effects on metabolic syndrome and mechanisms of triterpenoids using a metabolomic and lipidomic approach

Metabolomics and lipidomics combined with serum pharmacochemistry uncover the potential mechanism of Huang-Lian-Jie-Du decoction alleviates atherosclerosis in ApoE-/- mice

ETHNOPHARMACOLOGICAL RELEVANCE

Atherosclerosis (AS) is one of the main cardiovascular diseases (CVDs) leading to an increase in global mortality, and its key pathological features are lipid accumulation and oxidative stress. Huang-Lian-Jie-Du decoction (HLJDD), a representative formula for clearing heat and detoxifying, has been shown to reduce aortic lipid plaque and improve AS. However, multiple components and multiple targets of HLJDD pose a challenge in comprehending its comprehensive mechanism in the treatment of AS.

AIM OF THE STUDY

This study was designed to illustrate the anti-AS mechanisms of HLJDD in an apolipoprotein E-deficient (ApoE-/-) mouse model from a metabolic perspective.

MATERIALS AND METHODS

ApoE-/- mice were kept on a high-fat diet (HFD) to induce AS. Serum total cholesterol (TC), total triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were determined to evaluate the influence of HLJDD on dyslipidemia. Oil red O was used to stain mouse aortic lipid plaques, and hematoxylin and eosin (HE) staining was used to assess the pathological changes in the aortic roots. Metabolomics and lipidomics combined with serum pharmacochemistry were performed to research the HLJDD mechanism of alleviating AS.

RESULTS

In this study, HLJDD treatment improved serum biochemical levels and histopathological conditions in AS mice. A total of 6 metabolic pathways (arginine biosynthesis, glycerophospholipid, sphingolipid, arachidonic acid, linoleic acid, and glycerolipid metabolism) related to 25 metabolic biomarkers and 41 lipid biomarkers were clarified, and 22 prototype components migrating to blood were identified after oral administration of HLJDD.

CONCLUSION

HLJDD improved AS induced by HFD in ApoE-/- mice. The effects of HLJDD were mainly attributed to regulating lipid metabolism by regulating the metabolic pathways of glycerophospholipids, sphingolipids, arachidonic acid, linoleic acid, and glycerolipids and reducing the levels of oxidative stress by upregulating arginine biosynthesis.

Discovery and evaluation of active compounds from Xuanfei Baidu formula against COVID-19 via SARS-CoV-2 Mpro

BACKGROUND

The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) is still a widespread concern. As one of the effective traditional Chinese medicine (TCM) formulae, Xuanfei Baidu formula (XFBD) shows significant efficacy for treatment of COVID-19 patients. However, its antiviral active compounds and mechanism are still unclear.

PURPOSE

In this study, we explored the bioactive compounds of XFBD and its antiviral mechanism by integrating computational analysis and experimental testing.

METHODS

Focusing on the SARS-CoV-2 main protease (M^pro), as a key target in virus transcription and replication, the fluorescence resonance energy transfer (FRET) assay was built to screen out satisfactory natural inhibitors in XFBD. The surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) were undertaken to verify the binding affinity of ligand-M^pro. Omicron BA.1.1 and BA.2.3 variants were used to evaluate the antiviral activity of the focused compounds in non-cytotoxicity concentrations. For introducing the molecular mechanism, computational modeling and NMR spectra were employed to characterize the ligand-binding modes and identify the ligand-binding site on M^pro.

RESULTS

From a library of 83 natural compounds, acteoside, licochalcone B, licochalcone D, linoleic acid, and physcion showed the satisfactory inhibition effects on M^pro with IC₅₀ ranging from 1.93 to 42.96 µM, which were further verified by SPR. Showing the excellent binding affinity, acteoside was witnessed to gain valuable insights into the thermodynamic signatures by ITC and presented antiviral activity on Omicron BA.1.1 and BA.2.3 variants in vitro. The results revealed that acteoside inhibited M^pro via forming the hydrogen bond between 7-H of acteoside and M^pro.

CONCLUSION

Acteoside is regarded as a representative active natural compound in XFBD to inhibit replication of SARS-CoV-2, which provides the antiviral evidence and some insights into the identification of SARS-CoV-2 M^pro natural inhibitors.

The roles of serine hydrolases and serum albumin in alisol B 23-acetate hydrolysis in humans

Introduction: Alisol B 23-acetate (AB23A), a major bioactive constituent in the Chinese herb Zexie (Rhizoma Alismatis), has been found with multiple pharmacological activities. AB23A can be readily hydrolyzed to alisol B in mammals, but the hydrolytic pathways of AB23A in humans and the key enzymes responsible for AB23A hydrolysis are still unrevealed. This study aims to reveal the metabolic organs and the crucial enzymes responsible for AB23A hydrolysis in human biological systems, as well as to decipher the impact of AB23A hydrolysis on its biological effects. Methods: The hydrolytic pathways of AB23A in human plasma and tissue preparations were carefully investigated by using Q-Exactive quadrupole-Orbitrap mass spectrometer and LC-UV, while the key enzymes responsible for AB23A hydrolysis were studied via performing a set of assays including reaction phenotyping assays, chemical inhibition assays, and enzyme kinetics analyses. Finally, the agonist effects of both AB23A and its hydrolytic metabolite(s) on FXR were tested at the cellular level. Results: AB23A could be readily hydrolyzed to form alisol B in human plasma, intestinal and hepatic preparations, while human butyrylcholinesterase (hBchE) and human carboxylesterases played key roles in AB23A hydrolysis in human plasma and tissue preparations, respectively. It was also found that human serum albumin (hSA) could catalyze AB23A hydrolysis, while multiple lysine residues of hSA were covalently modified by AB23A, suggesting that hSA catalyzed AB23A hydrolysis via its pseudo-esterase activity. Biological tests revealed that both AB23A and alisol B exhibited similar FXR agonist effects, indicating AB23A hydrolysis did not affect its FXR agonist effect. Discussion: This study deciphers the hydrolytic pathways of AB23A in human biological systems, which is very helpful for deep understanding of the metabolic rates of AB23A in humans, and useful for developing novel prodrugs of alisol B with desirable pharmacokinetic behaviors.