Plant-derived virulence arresting drugs as novel antimicrobial agents: Discovery, perspective, and challenges in clinical use.

Antimicrobial resistance (AMR) emerges as a severe crisis to public health and requires global action. The occurrence of bacterial pathogens with multi-drug resistance appeals to exploring alternative therapeutic strategies. Antivirulence treatment has been a positive substitute in seeking to circumvent AMR, which aims to target virulence factors directly to combat bacterial infections. Accumulated evidence suggests that plant-derived natural products, which have been utilized to treat infectious diseases for centuries, can be abundant sources for screening potential virulence-arresting drugs (VADs) to develop advanced therapeutics for infectious diseases. This review sums up some virulence factors and their actions in various species of bacteria, as well as recent advances pertaining to plant-derived natural products as VAD candidates. Furthermore, we also discuss natural VAD-related clinical trials and patents, the perspective of VAD-based advanced therapeutics for infectious diseases and critical challenges hampering clinical use of VADs, and genomics-guided identification for VAD therapeutic. These newly discovered natural VADs will be encouraging and optimistic candidates that may sustainably combat AMR.

Screening of Potential α-Glucosidase Inhibitors from the Roots and Rhizomes of Panax Ginseng by Affinity Ultrafiltration Screening Coupled with UPLC-ESI-Orbitrap-MS Method.

Panax ginseng was a traditional Chinese medicine with various pharmacological activities and one of its important activities was hypoglycemic activity; therefore, panax ginseng has been used in China as an adjuvant in the treatment of diabetes mellitus. In vivo and in vitro tests have revealed that ginsenosides, which are derived from the roots and rhizomes of panax ginseng have anti-diabetic effects and produce different hypoglycemic mechanisms by acting on some specific molecular targets, such as SGLT1, GLP-1, GLUTs, AMPK, and FOXO1. α-Glucosidase is another important hypoglycemic molecular target, and its inhibitors can inhibit the activity of α-Glucosidase so as to delay the absorption of dietary carbohydrates and finally reduce postprandial blood sugar. However, whether ginsenosides have the hypoglycemic mechanism of inhibiting α-Glucosidase activity, and which ginsenosides exactly attribute to the inhibitory effect as well as the inhibition degree are not clear, which needs to be addressed and systematically studied. To solve this problem, affinity ultrafiltration screening coupled with UPLC-ESI-Orbitrap-MS technology was used to systematically select α-Glucosidase inhibitors from panax ginseng. The ligands were selected through our established effective data process workflow based on systematically analyzing all compounds in the sample and control specimens. As a result, a total of 24 α-Glucosidase inhibitors were selected from panax ginseng, and it was the first time that ginsenosides were systematically studied for the inhibition of α-Glucosidase. Meanwhile, our study revealed that inhibiting α-Glucosidase activity probably was another important mechanism for ginsenosides treating diabetes mellitus. In addition, our established data process workflow can be used to select the active ligands from other natural products using affinity ultrafiltration screening.

Comprehensive Identification of Ginsenosides in the Roots and Rhizomes of Panax ginseng Based on Their Molecular Features-Oriented Precursor Ions Selection and Targeted MS/MS Analysis.

Panax ginseng is widely used in Asian countries and its active constituents-ginsenosides-need to be systematically studied. However, only a small part of ginsenosides have been characterized in the roots and rhizomes of panax ginseng (RRPG) up to date, mainly because of a lack of the fragmentation ions of many more ginsenosides. In order to comprehensively identify ginsenosides in RRPG, molecular features of ginsenosides orienting precursor ions selection and targeted tandem mass spectrometry (MS/MS) analysis strategy were proposed in our study, in which the precursor ions were selected according to the molecular features of ginsenosides irrespective of their peak abundances, and targeted MS/MS analysis was then performed to obtain their fragmentation ions for substance characterization. Using this strategy, a total of 620 ginsenosides were successfully characterized in RRPG, including 309 protopanaxadiol-type ginsenosides, 258 protopanaxatriol-type ginsenosides and 53 oleanane-type ginsenosides. It is worth noting that, except for the known aglycones mass-to-charge ratio (m/z) 459, 475 and 455, twelve other aglycones, including m/z 509, 507, 493, 491, 489, 487, 477, 473, 461, 457, 443 and 441, were first reported in our experiment and they were probably the derivatizations of the protopanaxatriol and protopanaxadiol. Our study will not only help people to improve the cognition of ginsenosides in RRPG, but will also play a guiding and reference role for the isolation and characterization of potentially new ginsenosides from RRPG.

Improving natural products identification through molecular features-oriented precursor ion selection and targeted MS/MS analysis: a case study of Zhi-Ke-Yang-Yin capsule.

Chemical substance identification is an indispensable step in research on therapeutic materials based on traditional Chinese medicine and its formulas. The successful characterization of chemical substances mainly relies on high-quality MS/MS spectra. However, to date, relatively few studies have specifically addressed the issues of improving the acquisition of MS/MS spectra of compounds for characterization. The current auto-MS/MS mode, where the precursor ions are selected depending on their signal intensity, encounters a drawback when the sample contains many overlapping signals, leading to compounds with a lower or much lower abundance missing identification. To solve this problem, a strategy in which molecular features oriented precursor ion selection was followed by targeted MS/MS analysis for structure elucidation was proposed. The precursor ions were selected according to their first and second molecular features, namely m/z and retention time, irrespective of their intensities. By performing targeted MS/MS analysis, the MS/MS spectra of many more compounds of interest can be obtained, leading to an improvement in natural product identification. As an example, the chemical substances in the Zhi-Ke-Yang-Yin extract were analyzed using this strategy, and as a result, 431 ingredients were tentatively characterized, including both known and unknown or new compounds.

[Effect of Scutellariae Radix on expression of inflammatory cytokine protein and gene in lung of mice with viral pneumonia caused by influenza virus FM1 infection].

Mice models of viral pneumonia were induced by pulmonary adaptive strain FM1 of influenza A virus in Asian mice.RT-PCR and immunohistochemistry were used to dynamically observe the effect of Scutellariae Radix on the protein and gene expression of inflammatory cytokine in the lungs of the model mice infected by influenza virus FM1 at different phases. The partial mechanism of Scutellariae Radix in repairing the immune inflammatory damage of target organs of pneumonia caused by influenza virus was further explored. The results showed that Scutellariae Radix reduced protein and gene expression of proinflammatory cytokines tumor necrosis factor( TNF-α),interleukin IL-1,IL-6 in lung tissues from 3 rd to 5 th day after infection,and increased protein and gene expression of IL-10 and IFN-γ in lung tissues on the 5 th day after infection. Scutellariae Radix may inhibit excessive release of pro-inflammatory cytokines and promote the expression of anti-inflammatory cytokines,thereby inhibiting the systemic inflammatory response syndrome,reducing the immunoinflammatory pathological damage of lung caused by influenza virus FM1 infection,and promoting lung repair of tissue inflammatory lesions.

Screening Specific Biomarkers of Herbs Using a Metabolomics Approach: A Case Study of Panax ginseng.

Medicinal herbs belonging to the same genus are always easily confused due to their extremely similar morphology and metabolites. Previously, to differentiate them, inherently specific biomarkers were screened out via intuitive comparison of their metabolite profiles. Unfortunately, the selected biomarkers have worked only partially. Most significant specific biomarkers have been neglected. Herein, a novel method for screening specific biomarkers of medicinal herbs using a metabolomics technique was developed. Firstly, the profiles of a group of easily confused herbs belonging to the same genus were analyzed by ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry to detect all components, including low-response metabolites. Then, all components were compared between the different samples, and specific biomarkers were extracted by the metabolomics techniques of alignment, normalization, defining the sample sets, filtering by frequency and Venn diagram analysis with Mass Profiler Professional (MPP) software. Thirdly, the correlations of these biomarkers were investigated via partial correlational analysis to obtain the most representative specific biomarkers. As an example, selection of specific biomarkers for ginseng (Panax ginseng) was performed, and three specific biomarkers including chikusetsusaponin IVa, ginsenoside Rf and ginsenoside Rc were finally selected and verified as the most representative specific biomarkers of Panax ginseng.

Metabolism of 20(S)-Ginsenoside Rg2 by Rat Liver Microsomes: Bioactivation to SIRT1-Activating Metabolites.

20(S)-Ginsenoside Rg2 (1) has recently become a hot research topic due to its potent bioactivities and abundance in natural sources such as the roots, rhizomes and stems-leaves of Panax ginseng. However, due to the lack of studies on systematic metabolic profiles, the prospects for new drug development of 1 are still difficult to predict, which has become a huge obstacle for its safe clinical use. To solve this problem, investigation of the metabolic profiles of 1 in rat liver microsomes was first carried out. To identify metabolites, a strategy of combined analyses based on prepared metabolites by column chromatography and ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was performed. As a result, four metabolites M1-M4, including a rare new compound named ginsenotransmetin A (M1), were isolated and the structures were confirmed by spectroscopic analyses. A series of metabolites of 1, MA-MG, were also tentatively identified by UPLC-Q-TOF/MS in rat liver microsomal incubate of 1. Partial metabolic pathways were proposed. Among them, 1 and its metabolites M1, M3 and M4 were discovered for the first time to be activators of SIRT1. The SIRT1 activating effects of the metabolite M1 was comparable to those of 1, while the most interesting SIRT1 activatory effects of M3 and M4 were higher than that of 1 and comparable with that of resveratrol, a positive SIRT1 activator. These results indicate that microsome-dependent metabolism may represent a bioactivation pathway for 1. This study is the first to report the metabolic profiles of 1 in vitro, and the results provide an experimental foundation to better understand the in vivo metabolic fate of 1.

High-Performance Liquid Chromatography with Diode Array Detector and Electrospray Ionization Ion Trap Time-of-Flight Tandem Mass Spectrometry to Evaluate Ginseng Roots and Rhizomes from Different Regions.

Ginseng, Panax ginseng C. A. Meyer, is an industrial crop in China and Korea. The functional components in ginseng roots and rhizomes are characteristic ginsenosides. This work developed a new high-performance liquid chromatography coupled with electrospray ionization ion trap time-of-flight multistage mass spectrometry (LC-ESI-IT-TOF-MS(n)) method to identify the triterpenoids. Sixty compounds (1-60) including 58 triterpenoids were identified from the ginseng cultivated in China. Substances 1, 2, 7, 15-20, 35, 39, 45-47, 49, 55-57, 59, and 60 were identified for the first time. To evaluate the quality of ginseng cultivated in Northeast China, this paper developed a practical liquid chromatography-diode array detection (LC-DAD) method to simultaneously quantify 14 interesting ginsenosides in ginseng collected from 66 different producing areas for the first time. The results showed the quality of ginseng roots and rhizomes from different sources was different due to growing environment, cultivation technology, and so on. The developed LC-ESI-IT-TOF-MS(n) method can be used to identify many more ginsenosides and the LC-DAD method can be used not only to assess the quality of ginseng, but also to optimize the cultivation conditions for the production of ginsenosides.

Metabolomics study on the effects of Buchang Naoxintong capsules for treating cerebral ischemia in rats using UPLC-Q/TOF-MS.

ETHNOPHARMACOLOGICAL RELEVANCE: Buchang Naoxintong Capsules (BNC) are widely prescribed in Chinese medicine for the treatment of cerebrovascular and cardiovascular diseases. However, the therapeutic effects and mechanisms are not yet well understood. MATERIALS AND METHODS: In this study, a UPLC/TOF-MS-based metabolomic study was conducted to explore potential biomarkers that will increase our understanding of cerebral ischemia and to assess the integral efficacy of BNC in a middle cerebral artery occlusion (MCAO) rat model. Plasma metabolic profiles were analyzed and metabolic biomarkers were identified through multivariate data analysis. RESULTS: Clear separations were observed between the sham, MCAO and BNC-treated groups. We identified 28 biomarkers in the MCAO rats using variable importance for the projections (VIP) values (VIP>1) and a t-test (P<0.05). The identified biomarkers were mainly related to disturbances in monoamine neurotransmitter metabolism, amino acid metabolism, energy metabolism and lipid metabolism. Moreover, a correlation network diagram of the plasma biomarkers perturbed by MCAO was constructed. Some biomarkers, such as glutamine, PE (17:0), LysoPE (20:1), LysoPE (24:0), and the ratios of LysoPE (24:1) to LysoPE (24:0), LysoPE (24:2) to LysoPE (24:0), showed obvious changes and a tendency for returning to baseline values in BNC-treated MCAO rats. In addition, MCAO rats receiving BNC treatment had improved neurological deficits and reduced cerebral infarct size demonstrating the therapeutic potential of BNC for treating cerebral ischemia. CONCLUSION: This study provides a useful approach for exploring the mechanism of MCAO-induced cerebral ischemia and evaluating the efficacy of BNC.

Study on active ingredient and mechanism in preventing vascular dementia of Tianzhusan coming from Tujia medicine.

To make clear of the absorbed components of Tianzhusan (TZS) and its possible mechanism in preventing vascular dementia (VD), the rats' models of VD were prepared by a permanent ligation of the bilateral common carotid arteries. After 60 days, rats were administrated with TZS for 0.1 g x kg(-1), and the volume is 0.02 mL x g(-1). After 3 days, the medicated serum was prepared and detected by UPLC, and then we predicted the possible chemical structure of the absorbed components of TZS. According to the absorbed components, the potential targets of TZS were found by ligand profiling of Discovery Studio 3.5. All of these target genes were submitted to DAVID onine for gene set enrichment analysis (GSEA). The 5 absorbed components of TZS have been predicted, and four of them have been identified as parishin B, parishin C, parishin, pennogenin-3-O-alpha-L-rhamnopyranosy-(1-->2)-beta-D-glucoside. Through reverse finding targets, we got 861 pharmacophore models and 9 pathways from KEGG, BIOCARTA after document verification. These results showed that the efficacy mechanism of TZS on VD perhaps were be related with these absorbed components and pathways. If the traditional herbs could be proved effective by efficacy tests, the serum pharmacochemistry, computer-aided drug design, system biology and other technologies can be used in the next experiments, which will be beneficial to fast discovery of material basis and mechanisms of traditional medicine coming form ethnic minorities.

Identification of the chemical constituents of Chinese medicine Yi-Xin-Shu capsule by molecular feature orientated precursor ion selection and tandem mass spectrometry structure elucidation.

The incomplete identification of the chemical components of traditional Chinese medicinal formula has been one of the bottlenecks in the modernization of traditional Chinese medicine. Tandem mass spectrometry has been widely used for the identification of chemical substances. Current automatic tandem mass spectrometry acquisition, where precursor ions were selected according to their signal intensity, encounters a drawback in chemical substances identification when samples contain many overlapping signals. Compounds in minor or trace amounts could not be identified because most tandem mass spectrometry information was lost. Herein, a molecular feature orientated precursor ion selection and tandem mass spectrometry structure elucidation method for complex Chinese medicine chemical constituent analysis was developed. The precursor ions were selected according to their two-dimensional characteristics of retention times and mass-to-charge ratio ranges from herbal compounds, so that all precursor ions from herbal compounds were included and more minor chemical constituents in Chinese medicine were identified. Compared to the conventional automatic tandem mass spectrometry setups, the approach is novel and can overcome the drawback for chemical substances identification. As an example, 276 compounds from the Chinese Medicine of Yi-Xin-Shu capsule were identified.

Ginsenjilinol, a new protopanaxatriol-type saponin with inhibitory activity on LPS-activated NO production in macrophage RAW 264.7 cells from the roots and rhizomes of Panax ginseng.

One new dammarane triterpene saponin named ginsenjilinol (1) was isolated from the roots and rhizomes of Panax ginseng C.A. Mey., together with two known saponins ginsenoside Rf (2) and ginsenoside Re5 ( = panajaponol A, 3). Based on IR, HR-ESI-MS, and 1D as well as 2D NMR ((1)H-(1)H COSY, NOESY, HSQC, and HMBC) spectral data, the chemical structure of the new saponin was elucidated as 3ß,12ß,20S,26-tetrahydroxydammar-24E-en-6α-O-ß-d-glucopyranosyl-(1 â†’ 2)-O-ß-d-glucopyranoside. The ability of the isolated saponins to inhibit nitric oxide production by lipopolysaccharide-activated RAW 264.7 cells was also assayed. All of the isolated saponins exhibited the significant activity in a concentration-dependent manner at concentrations of 60-200 µM with the half maximal inhibitory concentration (IC50) values of 70.96 ± 2.05 µM for 1, 74.14 ± 2.65 µM for 2, and 79.83 ± 1.78 µM for 3, respectively, whereas indomethacin had an IC50 of 63.75 ± 3.33 µM as a positive control drug.

[Chemical constituents from roots and rhizomes of Panax ginseng cultivated in Jilin province].

The chemical constituents of the roots and rhizomes of Panax ginseng were systematically investigated by various column chromatographic methods including Amberlite XAD-4 macroporous adsorptive resins and silica gel as well as high-performance liquid chromatography, and their chemical structures were identified by physico-chemical properties and spectral analyses. Twenty-eight compounds were isolated from the 70% ethanolic-aqueous extract and identified as koryoginsenoside R1 (1), ginsenoside Rg1 (2), ginsenoside Rf (3), notoginsenoside R2 (4), ginsenoside Rg2 (5), notoginsenoside Fe (6), ginsenjilinol (7), ginsenoside Re5 (8), noto-ginsenoside N (9), notoginsenoside R1 (10), ginsenoside Re2 (11), ginsenoside Re1 (12), ginsenoside Re (13), ginsenoside Rs2 (14), ginsenoside Ro methyl ester (15), ginsenoside Rd (16), ginsenoside Re3 (17), ginsenoside Re4 (18), 20-gluco-ginsenoside Rf (19), ginsenoside Ro (20), ginsenoside Rc (21), quinquenoside-R1 (22), ginsenoside Ra2 (23), ginsenoside Rb1 (24), ginsenoside Ra1 (25), ginsenoside Ra3 (26), ginsenoside Rb2 (27), and notoginsenoside R4 (28). All isolated compounds are 20 (S) -protopanaxadiol or protopanaxatriol type triterpenoid saponins. Compound 1 was isolated from the roots and rhizomes of P. ginseng cultivated in Jilin province for the first time and compound 6 was isolated from the roots and rhizomes of P. ginseng for the first time. The 1H-NMR data of compounds 6, 14 and 19 were assigned for the first time.

Immunoregulatory and anti-tumor effects of polysaccharopeptide and Astragalus polysaccharides on tumor-bearing mice.

The aim of this study was to determine whether polysaccharopeptide (PSP) and Astragalus polysaccharides (APS) can be combined together as a new complex prescription (PSP + APS) for aiding adriamycin (AMD) chemotherapy. Ehrlich's ascites carcinoma (EAC) was used to establish a solid tumor model in Kunming mice. Immunocytochemical and immunohistochemical analysis were employed to detect the immunoregulatory and anti-tumor effects of EAC bearing mice after 30 days of administration with PSP and APS. PSP and PSP + APS could significantly increase the percentage of CD3(+) and CD4(+) T-lymphocytes, the ratio of CD4(+)/CD8(+), and the expression of IL-2/IL-2R in spleen and Bax in tumor tissue, but led to a diminution of Bcl-2 and CDK4 in tumor tissue compared with those of control group. In addition, PSP +APS could restore the immunological effects against AMD-induced immunosuppression, such as the subset of leukomonocyte, the expression of IL-2/IL-2R in the spleen, and the thymus index. These findings suggest that the immunomodulatory and anti-cancer effects of this new formula (PSP+APS) were better than those of PSP alone, and also could resist immunosuppression induced by AMD.

[Immunoregulatory activity of polysaccharopeptide and Astragalus polysaccharides on EAC tumor-bearing mice].

OBJECTIVE: To investigate the immunoregulatory activities of polysaccharopeptide and astragalus polysaccharides on EAC tumor-bearing mice. METHOD: Ehrlich's ascites carcinoma (EAC) Kunming (KM) mice were used to establish the animal model for solid tumor. Mice were randomly divided into six groups (n = 10): NS group (NS, 10 mL x kg(-1) x d(-1)), AMD group (AMD, 4 mg x kg(-1) x d(-1), 0.2 mL, only for the first 3 days), PSP group (PSP, 250 mg x kg(-1) x d(-1), 0.2 mL), APS group (APS, 250 mg x kg(-1) x d(-1), 0.2 mL), complex prescription group (PSP + APS, 250 mg x kg(-1) x d(-1), 0.1 mL) and combined treat group (AMD + PSP + APS, same dosage as above). After thirty days of treatment, immunocytochemical method was employed to detect the changes of T-lymphocyte subsets in the PBMC of tumor-bearing mice. Subsequently, the organ indexes and tumor inhibition rate were calculated and compared with those of control group. RESULT: Percentage of CD3+, CD4+ T-cell and the ratio of CD4+/CD8+ were obviously prominence in the PSP and PSP + APS groups compared with those of NS group (0.05), percentage of CD8+ T-cell was significantly decreased compared with that of AMD group; percentage of CD3+, CD4+ T-cell were obviously increased in AMD + PSP + APS group relative to that of AMD group; the thymus index of AMD group was significantly decreased compared with that of NS group, but the thymus index of AMD + PSP + APS group was obviously increased compared with that of AMD group; the weight of tumor in each administration group was significantly decreased compared with that of NS group. CONCLUSION: PSP and PSP + APS complex prescription showed the remarkable immunoregulation on EAC mice with chemotherapy or not.