Bioaffinity ultrafiltration coupled with HPLC-ESI-MS/MS for screening potential α-glucosidase inhibitors from pomegranate peel

A review on the in vitro and in vivo screening of α-glucosidase inhibitors

As a global metabolic disease, the control and treatment of diabetes have always been the focus of medical research. α-Glucosidase is a key enzyme in regulating blood glucose levels and has important applications in the treatment of diabetes. This review aims to explore the enzyme activity of α-glucosidase and its inhibition mechanism and evaluate the efficacy and limitations of existing inhibitor screening methods. First, the chemical structure, biological activity, and influencing factors of α-glucosidase on diabetes are discussed in detail. Then, the various methods that have been used to screen α-glucosidase inhibitors in recent years are reviewed, including in vivo animal experiments, in vitro experiments, and virtual molecular docking. The experimental principles, advantages, and limitations of each method and their application in discovering new inhibitors are also discussed. Finally, this review emphasizes the importance of developing efficient and safe α-glucosidase inhibitors, summarizes the advantages and disadvantages of various screening models, and proposes future research directions. This review comprehensively examines the enzyme activity of α-glucosidase and the screening methods for α-glucosidase inhibitors, provides an important perspective in the field of diabetes drug discovery and development, and provides a reference for future research.

Effects of Ellagic Acid on Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis

Background

Abnormal glucose and lipid metabolism (GALM) serve as both a cause and an inducer for the development of the disease. Improvement and treatment of GALM are an important stage to prevent the occurrence and development of the disease. However, current clinical treatment for GALM is limited. Ellagic acid (EA), a common polyphenol present in foods, has been shown to improve abnormalities in GALM observed in patients suffering from metabolic diseases.

Objective

This study used a meta-analysis method to systematically assess the effects of EA on GALM.

Method

As of November 8, 2023, a comprehensive search was conducted across 5 databases, namely, PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar to identify randomized controlled trials (RCTs) in which EA served as the primary intervention for diseases related to GALM. The risk of bias within the included studies was assessed according to the Cochrane Handbook. All statistical analyzes were performed using RevMan 5.4 software.

Results

In this study, a total of 482 articles were retrieved, resulting in the inclusion of 10 RCTs in the meta-analysis. The results showed that EA could reduce fasting blood glucose (FBG) (p = 0.008), increase insulin secretion (p = 0.01), improve insulin resistance index (HOMA-IR) (p = 0.003), decrease triglyceride (TG) (p = 0.004), and reduce cholesterol (Chol) (p = 0.04) and low-density lipoprotein (LDL-c) (p = 0.0004). EA had no significant effect on waist circumference (WC), body weight (BW), body mass index (BMI), 2 hours after prandial blood glucose (2 h-PG), total cholesterol (TC), and high-density lipoprotein (HDL-c).

Conclusions

The effect of improvement in glucose and lipids of EA was closely related to the dose and the intervention time. EA can improve GALM caused by diseases. To corroborate the findings of this study and improve the reliability of the results, EA is imperative to refine the research methodology and increase the sample size in future investigations.

Screening and identification of potential hypoglycemic and hypolipidemic compounds from aqueous extract of Scutellaria baicalensis Georgi root combing affinity ultrafiltration with multiple drug targets and in silico analysis

INTRODUCTION

Scutellaria baicalensis Georgi, a traditional Chinese medicine, is widely applied to treat various diseases among people, especially in East Asia. However, the specific active compounds in S. baicalensis aqueous extracts (SBAEs) responsible for the hypoglycemic and hypolipidemic properties as well as their potential mechanisms of action remain unclear.

OBJECTIVES

This work aimed to explore the potential hypoglycemic and hypolipidemic compounds from SBAE and their potential mechanisms of action.

METHODOLOGY

The in vitro inhibitory tests against lipase and α-glucosidase, and the effects of SBAE on glucose consumption and total triglyceride content in HepG2 cells were first performed to evaluate the hypoglycemic and hypolipidemic effects. Then, affinity ultrafiltration liquid chromatography-mass spectrometry (LC-MS) screening strategy with five drug targets, including α-glucosidase, α-amylase, protein tyrosine phosphatase 1B (PTP1B), lipase and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) was developed to screen out the potential active constituents from SBAE, and some representative active compounds were further validated.

RESULTS

SBAE displayed noteworthy hypoglycemic and hypolipidemic properties, and 4, 10, 4, 8, and 8 potential bioactive components against α-amylase, α-glucosidase, PTP1B, HMGCR, and lipase were initially screened out, respectively. The interaction network was thus constructed between the potential bioactive compounds screened out and their corresponding drug targets. Among them, baicalein, wogonin, and wogonoside were revealed to possess remarkable hypoglycemic and hypolipidemic effects.

CONCLUSION

The potential hypolipidemic and hypoglycemic bioactive compounds in SBAE and their mode of action were initially explored through ligand-target interactions by combining affinity ultrafiltration LC-MS strategy with five drug targets.

Multifunctional Pomegranate Peel Microparticles with Health-Promoting Effects for the Sustainable Development of Novel Nutraceuticals and Pharmaceuticals

Recovering the bioactive components from pomegranate peel (PP) in the fruit-processing industry has attracted great attention in terms of minimizing the waste burden, as well as providing a new source of a multitude of functional compounds. The present study aimed to develop a feasible microencapsulation process of PP extract by using pectin and a pectin/2-hydroxypropyl-β-cyclodextrin (HP-β-CD) blend as coating materials. Microsized powders obtained by a spray drying technique were examined in terms of technological characteristics, exhibiting high powder yield and desirable moisture content, flowability, and cohesive properties. Assuming that the interactions with the used biopolymers occur on the surface hydrophobic domain, their presence significantly improved the thermal stability of the microencapsulated powders up to 200 °C. The health-promoting effects of PP have been associated with its high content in ellagitannins, particularly punicalagin. The obtained PP powders exhibited strong antioxidant and hypoglycemic potential, while an antimicrobial assay revealed their potent activity against Gram-positive bacteria. Additionally, an in vitro release study suggested that the used biopolymers can modify the release of target bioactive compounds, thus establishing a basis for developing an oral-controlled release system. Altogether, biowaste valorization from PP by the production of effective multifunctional microsized powders represents a sustainable way to obtain novel nutraceuticals and/or pharmaceuticals.

Rapid identification of α-glucosidase inhibitors from Poria using spectrum-effect, component knock-out, and molecular docking technique

Instruction

Poria (Poria cocos) is known for its health-promoting effects and is consumed as a food due to its potential hypoglycemic activity. However, the composition of Poria is complex, and the bioactive compounds that inhibit α-glucosidase are not clear.

Methods

In this study, the fingerprint of the Poria methanol extract characterized by high-performance liquid chromatography (HPLC) and the model of the corresponding spectrum-effect relationship for α-glucosidase was first established to screen the active compounds from Poria. Then, the predicted bioactive compounds were knocked out and identified using mass spectrometry. Finally, the potential binding sites and main bonds of each compound with α-glucosidase were studied using molecular docking.

Results

The results have shown that at least 11 compounds from Poria could inhibit α-glucosidase effectively. Moreover, eight individual compounds, i.e., poricoic acid B (P8), dehydrotumulosic acid (P9), poricoic acid A (P10), polyporenic acid C (P12), 3- epidehydrotumulosic acid (P13), dehydropachymic acid (P14), 3-O-acetyl-16α-hydroxytrametenolic acid (P21), and pachymic acid (P22), were identified, and they exhibited effective inhibitory activity against α-glucosidase.

Discussion

The possible inhibitory mechanism of them based on molecular docking showed that the binding sites are mainly found in the rings A, B, and C of these compounds, and C-3 C-16 and side chains of C-17, with the phenylalanine, arginine, tyrosine, histidine, and valine of α-glucosidase. The main interactions among them might be alkyl and hydrogen bonds, which theoretically verified the inhibitory activity of these compounds on α-glucosidase. The achievements of this study provided useful references for discovering bioactive compounds with hypoglycemic effects from Poria.

Inhibition mechanism of α-glucosidase inhibitors screened from Tartary buckwheat and synergistic effect with acarbose

Tartary buckwheat has been shown to provide a good antihyperglycemic effect. However, it is unclear which active compounds play a key role in attenuating postprandial hyperglycemia. Presently, acetone extract from the hull of Tartary buckwheat had the best effect for α-glucosidase inhibition (IC₅₀ = 0.02 mg/mL). Twelve potential α-glucosidase inhibitors from Tartary buckwheat were screened and identified by the combination of ultrafiltration and high-performance liquid chromatography coupled with mass spectrometry. Myricetin and quercetin exhibited the highest anti-α-glucosidase activity with IC₅₀ values of 0.02 and 0.06 mg/mL, respectively. These inhibitors manifested different types of inhibition manners against α-glucosidase via direct interaction with the amino acid residues. The results of structure-activity relationships indicated that an increase in the number of -OH on the B-ring greatly strengthened α-glucosidase inhibitory activity, but glucoside and rutinoside replacement on the C-ring obviously weakened this influence. Furthermore, a synergistic effect was observed between inhibitors with different inhibition manners.