Antimicrobial Effects and Mechanisms of Ethanol Extracts of Psoralea corylifolia Seeds Against Listeria monocytogenes and Methicillin-Resistant Staphylococcus aureus

A review of Psoralea corylifolia L.: a valuable plant with profound biological significance

Psoralea corylifolia L. (PCL) is an annual herb of the genus Psoralea in the family Fabaceae, and its mature fruit can be used medicinally as a precious medicinal herb to tonify muscles and bones. With the deepening of research, its applications to various industries, including food, agriculture, and cosmetics, with products being developed in countries such as Vietnam, India, and Japan. A total of 321 metabolites, including coumarins, flavonoids, meroterpenes, benzofurans, and dimers, were identified in PCL. PCL and related products have demonstrated therapeutic effects, such as antiosteoporosis effects, estrogen-like effects, anti-inflammatory properties, neuroprotection, antitumor activity, and vitiligo treatment. The expression mechanisms of these pharmacological effects are closely related to the regulation of the immune system, the inhibition of oxidative stress, and the induction of apoptosis. This paper summarizes the latest research on the ethnobotany, phytochemistry, processing technology, pharmacology, and hepatotoxicity of PCL. Furthermore, bibliometric analysis was used to systematically analyze the research hotspots and trends in PCL, which have never been addressed in previous reviews of PCL. In the future, it will be necessary to focus on the active metabolites of PCL, analyze its targets and signaling pathway network to address potential toxicity and side effects in clinical applications, and further expand the potential application of PCL in medicine.

Exploring the potential of 1,8-cineole from cardamom oil against food-borne pathogens: Antibacterial mechanisms and its application in meat preservation

Food-borne pathogenic bacteria are a major public health concern globally. Traditional control methods using antibiotics have limitations, leading to the exploration of alternative strategies. Essential oils such as cardamom possess antimicrobial properties and have shown efficacy against food-borne pathogenic bacteria. The utilization of essential oils and their bioactive constituents in food preservation is a viable strategy to prolong the shelf-life of food products while ensuring their quality and safety. To the best of our knowledge, there are no studies that have utilized 1,8-cineole (the main active constituent of cardamom essential oil) as a preservative in meat, so this study might be the first to utilize 1,8-cineole as an antibacterial agent in meat preservation. The application of 1,8-cineole had a significant suppressive impact on the growth rate of Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium in meat samples stored for 7 days at 4 °C. Additionally, the surface color of the meat samples was not negatively impacted by the application of 1,8-cineole. The minimum inhibitory concentration was 12.5-25 mg/ml, and the minimum bactericidal concentration was 25-50.0 mg/ml. The bacterial cell membrane may be the target of cardamom, causing leakage of intracellular proteins, ATP, and DNA. The obtained data in this study may pave a new avenue for using 1,8-cineole as a new perspective for dealing with this problem of food-borne pathogens and food preservation, such as meat.

Natural Antimicrobials: A Reservoir to Contrast Listeria monocytogenes

Natural environments possess a reservoir of compounds exerting antimicrobial activity that are forms of defence for some organisms against others. Recently, they have become more and more attractive in the food sector due to the increasing demand for natural compounds that have the capacity to protect food from pathogenic microorganisms. Among foodborne pathogens, Listeria monocytogenes can contaminate food during production, distribution, or storage, and its presence is especially detected in fresh, raw food and ready-to-eat products. The interest in this microorganism is related to listeriosis, a severe disease with a high mortality rate that can occur after its ingestion. Starting from this premise, the present review aims to investigate plant extract and fermented plant matrices, as well as the compounds or mixtures of compounds produced during microbial fermentation processes that have anti-listeria activity.

Lipidomics reveals the lipid metabolism disorders in Fructus Psoraleae-induced hepatotoxicity in rats with kidney-yin deficiency syndrome

Fructus Psoraleae (FP), one of the important traditional Chinese medicines, is widely used in clinic and has been reported to be hepatotoxic. However, there is no report on the mechanism of FP-induced hepatotoxicity based on the theory of You Gu Wu Yun. In this study, plasma samples of rats with different kidney deficiency syndromes were investigated using a lipidomics approach based on UPLC/Q-TOF-MS technique. Firstly, multivariate statistical analysis, VIP value test, statistical test and other methods were used to find the lipid metabolites in the two syndrome model groups that were different from the normal group. The screening of differential lipid metabolites revealed that there were 12 biomarkers between the blank group and the kidney-yang deficiency model group as well as 16 differential metabolites between the kidney-yin deficiency model group, and finally a total of 17 relevant endogenous metabolites were identified, which could be used as differential lipid metabolites to distinguish between kidney-yin deficiency and kidney-yang deficiency evidence. Secondly, the relative content changes of metabolites in rats after administration of FP decoction were further compared to find the substances associated with toxicity after administration, and the diagnostic ability of the identified biomarkers was evaluated using a receiver operating characteristic curve (ROC). Results a total of 14 potential differential lipid metabolites, including LysoPC(20:0/0:0) and LysoPC(16:0/0:0), which may be related to hepatotoxicity in rats with kidney-yin deficiency syndrome were further screened, namely, the potential active lipid metabolites related to hepatotoxicity in rats induced by FP. Finally, cluster analysis, MetPA analysis and KEGG database were used to analyze metabolic pathways. It was discovered that the metabolism of glycerophospholipid and sphingolipid may be strongly related to the mechanism of hepatotoxicity brought on by FP. Overall, we described the lipidomics changes in rats treated with FP decoction and screened out 14 lipid metabolites related to hepatotoxicity in rats with kidney-yin deficiency, which served as a foundation for the theory of "syndrome differentiation and treatment" in traditional Chinese medicine and a guide for further investigation into the subsequent mechanism.

A practical method for rapid discrimination of constituents in Psoraleae Fructus by UPLC-Q-Orbitrap MS

Psoraleae Fructus (PF) is one of the most frequently used traditional Chinese medicine, which has good efficacy in warming kidney to activate yang, promoting inspiration to relieve asthma and warming spleen to stop diarrhea. However, the chemical composition of PF is complex, which makes it difficult to determine its active and toxic components. In order to rapidly classify and identify the chemical components of the extracts from PF, this research was processed with CNKI, PubMed, and PubChem databases and data post-processing technique basing on ultrahigh performance liquid chromatography quadrupole orbitrap mass spectrometry (UPLC-Q-Orbitrap MS) technique. Finally, 73 chemical components were discriminated, including 44 flavonoids, 18 coumarins, and 11 terpenoids, with the cleavage rules of each chemical component summarized. This study established a UPLC-Q-Orbitrap MS method for the separation and discrimination of the chemical constituents of PF, which can lay a foundation for the further study of its medicinal substances and quality control.

Unveiling hepatotoxicity distinction of coumarin-related compounds from glycosides to aglycones in Fructus Psoraleae by integrating UPLC-Q-TOF-MS and high content analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Fructus Psoraleae (FP), the dried and ripe fruit of Cullen corylifolium (L.) Medik., is widely used due to its various clinical pharmacological effects, but its hepatotoxicity restricts its clinical application. So far, its hepatotoxic components and their underlying mechanism have not been systematically elucidated.

AIM OF THE STUDY

This study was undertaken to reveal the hepatotoxicity distinction of coumarin-related compounds from glycosides to aglycones in FP and elucidate their potential mechanism.

METHODS

Rats were administrated with the aqueous extract of Fructus Psoraleae (AEFP), in which eight coumarin-related compounds were focused. Subsequently, compounds exposed in rats' livers were detected by UPLC-Q-TOF-MS, and the identified hepatotoxic compounds were evaluated to elaborate their possible mechanism by the aid of high content analysis (HCA).

RESULTS

Eight coumarin-related compounds were identified, among which psoralenoside (PO), isopsoralenoside (IPO), psoralen (P), and isopsoralen (IP) were the principally exposed compounds in rats' livers. Furocoumarinic acid glucoside (FAG), (E)-3-(4-(((2S, 3R, 4S, 5S, 6R)-3,4,5-trihydroxy-6-(hydroxymethyl) tetrahydro-2H-pyran-2-yl) oxy) benzofuran-5-yl) acrylic acid (isofurocoumarinic acid glucoside, IFAG), furocoumarinic acid (FA), and (E)-3-(4-hydroxybenzofuran-5-yl) acrylic acid (isofurocoumarinic acid, IFA) were also detected in low abundance. P, IP, FA, and IFA were identified as the hepatotoxic compounds, while their glycosides were almost non-hepatotoxic. The HCA's results showed that hepatotoxic compounds disrupted the balance in reactive oxygen species (ROS), nuclear area, and mitochondrial membrane potential of HepG2 cells, leading to the occurrence of hepatotoxicity.

CONCLUSIONS

P, IP, FA, and IFA were identified as hepatotoxic compounds, from which P and IP were proposed as the important risk components for hepatotoxicity. The conversion from glycosides to aglycones played an essential role in FP-induced hepatotoxicity.

A new approach to overcoming antibiotic-resistant bacteria: Traditional Chinese medicine therapy based on the gut microbiota

With the irrational use of antibiotics and the increasing abuse of oral antibiotics, the drug resistance of gastrointestinal pathogens has become a prominent problem in clinical practice. Gut microbiota plays an important role in maintaining human health, and the change of microbiota also affects the activity of pathogenic bacteria. Interfering with antibiotic resistant bacteria by affecting gut microbiota has also become an important regulatory signal. In clinical application, due to the unique advantages of traditional Chinese medicine in sterilization and drug resistance, it is possible for traditional Chinese medicine to improve the gut microbial microenvironment. This review discusses the strategies of traditional Chinese medicine for the treatment of drug-resistant bacterial infections by changing the gut microenvironment, unlocking the interaction between microbiota and drug resistance of pathogenic bacteria.

Selection and validation of reference genes for quantitative real-time PCR normalization in Psoralea corylifolia (Babchi) under various abiotic stress

Psoralea corylifolia L. is a popular herb and has long been used in traditional Ayurvedic and Chinese medicine owing to its extensive pharmacological activities, especially in the treatment of various shin diseases. To date, the systematic evaluation and selection of the optimum reference genes for gene expression analysis of P. corylifolia were not reported. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is a method for gene expression quantification. Selecting appropriate reference genes is the prerequisite for accurate normalization of RT-qPCR results. This study assessed the expression stability of 10 candidate reference genes under different abiotic stresses. First, amplification primers for RT-qPCR were designed and received testing and optimization. Then, expression data from each candidate gene were evaluated based on three statistical algorithms, and their results were further integrated into a comprehensive ranking based on the geometric mean. Additionally, one target gene, i.e., 1-aminocyclopropane-1-carboxylate oxidase (ACO), was used to validate the effectiveness of the selected reference. Our analysis suggested that thioredoxin-like protein YLS8 (YLS8), TIP41-like family protein (TIP41), and cyclophilin 2 (CYP2) genes provided superior expression normalization under different abiotic stresses. Overall, this work constitutes the first effort to select optimal endogenous controls for RT-qPCR studies of gene expression in P. corylifolia. It also provides a reasonable normalization standard and basis for further analysis of the gene expression of bioactive components in P. corylifolia.

In Vitro Antibacterial Experiments of Qixingjian Decoction and Its Synergistic Interaction with Oxacillin against Clinical Isolates of Methicillin-Resistant Staphylococcus aureus

Background

With the widespread use and abuse of antimicrobial drugs, the problem of bacterial resistance is becoming increasingly prominent. The clinical detection rate of drug-resistant bacteria is increasing year by year, so there is an urgent need to develop new antimicrobial drugs. Qixingjian Decoction (QXJT) is a formula commonly used in Chinese medicine for the treatment of sepsis caused by acute purulent infections of the face, hands, and feet. There are many compounds with antimicrobial effects that are available, but little is known about their mode of action. In this study, we mainly evaluated the antimicrobial activity of QXJT and explored its synergistic interaction with oxacillin (OX) and the mechanism of its antimicrobial activity.

Methods

The antimicrobial activity of QXJT against methicillin-resistant Staphylococcus aureus (MRSA) was determined by the microdilution method, the broth macrodilution method, and the time-kill curve method. The main compounds in QXJT were analyzed by ultra-performance liquid chromatography. The synergistic interaction of QXJT and oxacillin (OX) was determined by checkerboard assay, and the antimicrobial mechanism of QXJT, OX, and QXJT + OX was evaluated by transmission electron microscopy (TEM) technique. The expression of MRSA superantigen virulence factors (sea, seb, and tst), and drug resistance gene (mecA) was detected to provide a new strategy for new antibiotic drugs.

Results

QXJT exhibited antimicrobial activity against both clinical isolates of MRSA, MICs ranging from 18.75 to 37.5 mg/mL. Active substances such as Scutellarein, Scutellarin, Apigenin, and Wogonin 7-O-glucuronide were detected in the phytochemical analysis that may be associated with the antimicrobial activity of QXJT. The synergistic effect of QXJT and OX was determined by checkerboard assay (FICI = 0.5), and TEM images showed that QXJT could cause the disruption of MRSA cell wall, and QXJT + OX could produce greater disruption of MRSA cell wall, elucidating the synergistic effect of the two together on cell wall disruption by microscopic mechanisms. Our study shows that the combination of QXJT and OX can inhibit the expression of MRSA virulence factor, reduce the virulence of MRSA, and have no significant effect on the expression of MRSA resistance gene mecA.

Conclusion

The results of this study provide scientific experimental data for the traditional application of QXJT and initially explore the mechanism of action of QXJT combined with OX.

Synergistic evaluation of Moringa oleifera extract and ß-lactam antibiotic to restore the susceptibility of methicillin-resistant Staphylococcus aureus

INTRODUCTION

The antibiotic resistance has become a major threat to global health. The combinatorial use of two or more compounds to develop a new formulation may overcome the emerging cases of drug resistance. Moringa oleifera has been utilized as a strong nutritional, immunomodulator and therapeutic agent for decades. In this study, different parts of Moringa oleifera were screened for bioactive compounds that can act as a resistance modifying agent for multi-drug resistant organisms (MDROs).

METHODOLOGY

Initially, the combined effect of stem bark extracts and ampicillin was calculated by checkerboard assay. Active compounds of effective extract were assessed by High Performance Liquid Chromatography (HPLC). Minimal Inhibitory Concentration (MIC) and Fractional Inhibitory Concentration Index (FICI) were calculated to evaluate the synergistic behavior of stem bark extract with ampicillin. To study the blocking of resistance pathways of Methicillin-Resistant Staphylococcus aureus (MRSA) western blot was performed.

RESULTS

The results revealed that stem bark has significant anti-MRSA activity. The methanolic extract of stem bark in combination with ampicillin showed the highest synergistic effect (FICI value ≤ 0.237) against MRSA. Killing kinetics and membrane potential of ampicillin alone and in combination revealed an increase in the inhibitory potential of ampicillin against MRSA. Decolourization in iodometric assay confirmed the inhibition of β-lactamase, western blot results confirmed the blocking of penicillin-binding protein (PBP2a) expression with the restoration of MRSA sensitivity against β-lactams.

CONCLUSION

It can be concluded that methanolic extract of Moringa oleifera stem bark has bioactive compounds and can be used as an adjuvant with antibiotics to modify the resistance of MDROs.

Eleutheroside K Isolated from Acanthopanax henryi (Oliv.) Harms Inhibits the Expression of Virulence-Related Exoproteins in Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus (S.) aureus (MRSA) is a representative pathogen that produces numerous virulence factors involving manifold cytotoxins and exotoxins. The present study was designed to investigate the influence of Eleutheroside K (ETSK), a single compound isolated from the leaves of Acanthopanax (A.) henryi (Oliv.) Harms, on the exotoxins secreted by MRSA. The transcription and translation of the exotoxins (α-hemolysin and staphylococcal enterotoxins) related to virulence in S. aureus were determined via quantitative RT-PCR and western blot analysis. The effect of ETSK on the production of tumor necrosis factor (TNF)-α was evaluated using enzyme-linked immunosorbent assay. As a result, ETSK at sub-MIC concentrations could reduce the protein expression of α-hemolysin and enterotoxin, and the expression of genes that regulate virulence factors was also inhibited. In addition, the TNF-inducing activity of S. aureus was attenuated by ETSK in a dose-dependent manner. These results revealed that ETSK not only reduced the protein and gene expression levels of related exotoxins but also suppressed the ability of S. aureus to induce macrophages to release cytokines. This study indicated that the inhibition of MRSA infection by ETSK may be achieved by reducing the virulence of S. aureus and highlighted the potential of ETSK as an innovative strategy for the prevention and treatment of MRSA infections.

Hurdle Effects of Ethanolic Plant Extracts with Antimicrobials Commonly Used in Food against Foodborne Pathogenic Escherichia coli

Escherichia coli (E. coli) O157:H7 is a major foodborne pathogen that causes severe human infections. Plant extracts, glycine, and sodium acetate (NaOAc) exert antimicrobial effects that can be used to control pathogenic E. coli. However, their combinations have not been investigated. Thus, this study investigates the combination of ethanolic plant extracts with glycine and NaOAc against E. coli at various pH and temperature levels. Clove and rosemary extracts exhibited significant (p ≤ 0.05) antimicrobial activity against E. coli. At neutral pH, the combination of plant extracts with 1.0% glycine or 0.1% NaOAc reduced the minimum inhibitory concentration of clove from 0.4% to 0.2%; at pH 5.5, clove (0.1%) and rosemary (0.2%) extracts supplemented with NaOAc (0.1%) showed an additive effect. The population of E. coli O157:H7 in phosphate-buffered saline with 0.2% clove extract, 2% glycine, and 2% NaOAc showed a more than 5 log reduction after incubation at 15 °C for 96 h, while the combination of 0.1% clove extract with 2% NaOAc at pH 5.5 completely inhibited E. coli within 24 h at 35 °C. Thus, the combination of plant extracts with glycine and NaOAc could serve as a promising hurdle technology in controlling the growth of E. coli.

Novel Opportunity to Reverse Antibiotic Resistance: To Explore Traditional Chinese Medicine With Potential Activity Against Antibiotics-Resistance Bacteria

Antibiotic resistance is becoming significantly prominent and urgent in clinical practice with the increasing and wide application of antibacterial drugs. However, developing and synthesizing new antimicrobial drugs is costly and time-consuming. Recently, researchers shifted their sights to traditional Chinese medicine (TCM). Here, we summarized the inhibitory mechanism of TCM herbs and their active ingredients on bacteria, discussed the regulatory mechanism of TCM on antibiotic-resistant bacteria, and revealed preclinical results of TCM herbs and their active components against antibiotic-resistant bacteria in mouse models. Those data suggest that TCM herbs and their effective constituents exhibit potential blockage ability on antibiotic-resistant bacteria, providing novel therapeutic ideas for reversing antibiotic resistance.

Eleutheroside K isolated from Acanthopanax henryi (Oliv.) Harms suppresses methicillin resistance of Staphylococcus aureus

Acanthopanax (A.) henryi (Oliv.) Harms contain many bioactive compounds commonly used in traditional Chinese medicine. The objective of the present study was to investigate the antibacterial activity of the single constituent, Eleutheroside K (ETSK) isolated from the leaves of A. henryi (Oliv.) Harms, against methicillin-resistant Staphylococcus (S.) aureus (MRSA). Broth microdilution assay was used to measure the minimal inhibitory concentration (MIC) and the MIC values of ETSK against eight clinical S. aureus strains were all 50 µg ml^-1 . At sub-inhibitory concentrations, a synergistic effect between oxacillin (OXA) and ETSK was confirmed using checkerboard dilution assay and time-kill curve analysis. The bacteriostatic effect became more pronounced when ETSK was used in combination with detergent (Triton X-100) or ATPase inhibitor (N, N'-dicyclohexylcarbodiimide). According to western blot analysis, the down-regulated expression of Penicillin-binding protein 2a (PBP2a) further validated that the bacterial activity was inhibited when treated with ETSK in a dose-dependent manner. Results based on our study verified that ETSK significantly suppressed MRSA infections and emphasized the potential application of ETSK as a novel anti-MRSA natural drug.

Anti-inflammatory Effect of Astragalin and Chlorogenic Acid on Escherichia coli-Induced Inflammation of Sheep Endometrial Epithelium Cells

Endometritis is one of the main diseases which harm sheep husbandry. Astragalin and chlorogenic acid (CGA) are common active ingredients of traditional Chinese medicine (TCM) with immunoprotective, antioxidant, and anti-inflammatory properties. In the present study, sheep endometrial epithelium cells (SEECs) were successfully purified and identified, and the in vitro inflammation model of SEECs induced by Escherichia coli (E. coli) was successfully established. To explore the effect of astragalin and CGA on the inflammation induced by E. coli and its potential mechanism, six groups were set up, namely, group C, M, astragalin, CGA, BAY, and STR. Cells in group C were incubated with DMEM/F12 for 6 h, while cells in group M, astragalin, CGA, BAY, and STR were incubated with DMEM/F12, astragalin, CGA, BAY, and STR for 3 h, respectively, followed by E. coli infection at a multiplicity of infection (MOI) of 1 E. coli per cell for 3 h. Subsequently, the cells and the supernatant were collected to detect the expression of genes in the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) pathway by ELISA, qPCR, and western blot. The results showed that E. coli could induce inflammation of SEECs in vitro, while astragalin and CGA could alleviate the inflammatory response induced by E. coli via inhibiting the activation of the TLR4/NF-κB signaling pathway, which provides a theoretical and experimental foundation for preventing sheep endometritis clinically.

The Accumulation of Psoralen Contributes to Its Hepatotoxicity Revealed by Pharmacokinetic and Toxicokinetic Study after Repeated Administration

Psoralen is a furanocoumarin compound found in many herb medicines and is claimed to contribute to the hepatotoxicity caused by lots of traditional Chinese medicine. So far, there has been no research on the differences in pharmacokinetics of single and repeated dosing of psoralen. Moreover, the research on the cumulative toxicity of low concentration and long-term administration on cells has not been reported. Therefore, this study investigated the pharmacokinetic differences and the accumulated cytotoxicity of psoralen from repeated administration. The study found that after single or repeated administration of psoralen for 3 months at various dosages (14, 28, and 56 mg/kg), the pharmacokinetic parameters of female rats between single dose and repeated dose administration are totally different. Compared with a single administration, multiple administrations increased psoralen's in vivo exposure, prolonged the peak time, prolonged the half-life of the drug, reduced the drug clearance rate, and prolonged the drug's stay in the body. HepG2 cells were exposed to low doses (5, 10, 20, or 40 μM) of psoralen for 1, 2, 3, or 4 days. A 20 and 40 μM dose of psoralen did not induced cell death in the 1st day but significantly decreased the cell viability at the 3rd and 4th day of repeated administration, respectively. In addition, multiple administrations of psoralen decreased cell viability due to G2 arrest.