Simultaneously characterization of multiple constituents in Valeriana jatamansi Jones using an online supercritical fluid extraction-high-performance liquid chromatography/supercritical fluid chromatography-mass spectrometry system.

Valeriana jatamansi Jones is a commonly used traditional Chinese medicine, boasting rich effective compositions with versatile chemical structures and wide polarity, including iridoids, chlorogenic acid, and flavonoids. Previous reports indicate that conventional high-performance liquid chromatography (HPLC) analytical methods have proven inefficient performance in comprehensively characterizing components in Valeriana jatamansi. In the present study, a hybrid online analytical platform combining supercritical fluid extraction with both conventional HPLC separation (reverse phase) and supercritical fluid chromatography (normal phase) has been established and validated. This system can provide online extraction with two different chromatographic separation modes to increase separation ability and has been connected to a mass spectrometer to acquire high-resolution mass spectrometry data. Then, the online platform was applied to screening components in Valeriana jatamansi. A total of 117 compounds were identified, including five lignans, 18 organic acids, six flavonoids, and 88 iridoids. Thirty-three compounds were reported from Valeriana jatamansi for the first time. These results enrich our understanding of the components of Valeriana jatamansi and prove that the developed online platform in this study is a robust approach for accelerating working efficiency in comprehensively analyzing complicated samples.

Natural products from traditional medicine as promising agents targeting at different stages of oral biofilm development.

Oral cavity is an ideal habitat for more than 1,000 species of microorganisms. The diverse oral microbes form biofilms over the hard and soft tissues in the oral cavity, affecting the oral ecological balance and the development of oral diseases, such as caries, apical periodontitis, and periodontitis. Currently, antibiotics are the primary agents against infectious diseases; however, the emergence of drug resistance and the disruption of oral microecology have challenged their applications. The discovery of new antibiotic-independent agents is a promising strategy against biofilm-induced infections. Natural products from traditional medicine have shown potential antibiofilm activities in the oral cavity with high safety, cost-effectiveness, and minimal adverse drug reactions. Aiming to highlight the importance and functions of natural products from traditional medicine against oral biofilms, here we summarized and discussed the antibiofilm effects of natural products targeting at different stages of the biofilm formation process, including adhesion, proliferation, maturation, and dispersion, and their effects on multi-species biofilms. The perspective of antibiofilm agents for oral infectious diseases to restore the balance of oral microecology is also discussed.

Research progress on curcumin-mediated photodynamic therapy for oral infectious diseases / 口腔疾病防治

@#Curcumin is a natural medicine with a wide range of sources and low toxicity. It has antibacterial, antifungal, anti-inflammatory and other pharmacological effects. In recent years, curcumin has attracted much attention in the field of prevention and treatment of oral infectious diseases. Single curcumin is easily degraded during application and has poor water solubility and low bioavailability, but it can be used as a natural photosensitizer to mediate photodynamic treatment of oral infections. Photodynamic therapy has high antibacterial efficiency and can better protect the appearance and function of the affected area. This article reviews the research on curcumin-mediated photodynamic therapy for oral infectious diseases. As a natural photosensitizer, curcumin mediates photodynamic therapy and has shown good therapeutic effects against dental caries, endodontics, periodontitis, oral candidiasis and other oral infectious diseases by enhancing antibacterial ability, increasing the production of reactive oxygen species, and inhibiting the formation of biofilms. In-depth exploration of the mechanism of action of curcumin-mediated photodynamic therapy in different oral infectious diseases can provide new strategies for the prevention and treatment of oral infectious diseases.

Artemisinin elevates ergosterol levels of Candida albicans to synergise with amphotericin B against oral candidiasis.

Oral candidiasis, especially caused by Candida albicans, is the most common fungal infection of the oral cavity. The increase in drug resistance and lack of new antifungal agents call for new strategies of antifungal treatment. This study repurposed artemisinin (Art) as a potentiator to the polyene amphotericin B (AmB) and characterised their synergistic mechanism against C. albicans and oral candidiasis. The synergistic antifungal activity between Art and AmB was identified by the checkerboard and recovery plate assays according to the fractional inhibitory concentration index (FICI). Art showed no antifungal activity even at >200 mg/L. However, it significantly reduced AmB dosages against the wild-type strain and 75 clinical isolates of C. albicans (FICI ≤ 0.5). Art significantly upregulated expression of genes from the ergosterol biosynthesis pathway (ERG1, ERG3, ERG9 and ERG11), as shown by RT-qPCR, and elevated the ergosterol content of Candida cells. Increased ergosterol content significantly enhanced binding between fungal cells and the polyene agent, resulting in sensitisation of C. albicans to AmB. Drug combinations of Art and AmB showed synergistic activity against oral mucosal infection in vivo by reducing the epithelial infection area, fungal burden and inflammatory infiltrates in murine oropharyngeal candidiasis. These findings indicate a novel synergistic antifungal drug combination and a new Art mechanism of action, suggesting that drug repurposing is a clinically practical means of antifungal drug development and treatment of oral candidiasis.

[Effects of Artemisinin and Its Derivatives on Oral Microbes].

The oral environment provides suitable conditions for the colonization of various microorganisms. However, the oral microbials could be the initial factors of some kinds of oral infectious diseases, therefore the treatment against oral microbial pathogens has become an effective strategy. Artemisinin, a kind of sesquiterpene lactone extracted from Traditional Chinese Medicine Artemisia annua L., is the first-line therapy to treat tertian malaria, subtertian malaria and anti-chloroquine malaria for its high efficiency and low toxicity. In recent years, artemisinin and its derivatives have also been proven to be effective against bacteria, fungi, viruses, parasites, and tumors, some of which are closely related to oral diseases. In this review, we summarize the potential effects of artemisinin and its derivatives on oral microorganism by analyzing previous research and latest progress to provide the evidence for further improvement, and look forward to the new research directions. Further studies are needed to improve existing technologies and standards to clarify the effects of artemisinin and its derivatives on microorganisms with controversial effects, to expand the detection of microorganisms associated with oral infectious diseases, and to clarify the interaction with existing antifungal agents in the field of antifungal diseases. In addition, in the study of anti-oral infectious diseases, artemisinin and its derivatives' administration scheme, potential drug interactions, toxic and side effects and other aspects are necessary conditions for further research, which is also a new direction of research. With the maturity of the production process, the improvement of relevant research and the potential demand for the treatment of oral infectious diseases, artemisinin and its derivatives have a broad prospect in the field of oral microorganisms, and provide a new opportunity for the research and development of oral drugs.

Generation of Fluorinated Amychelin Siderophores against Pseudomonas aeruginosa Infections by a Combination of Genome Mining and Mutasynthesis.

Pioneering microbial genomic surveys have revealed numerous untapped biosynthetic gene clusters, unveiling the great potential of new natural products. Here, using a combination of genome mining, mutasynthesis, and activity screening in an infection model comprising Caenorhabditis elegans and Pseudomonas aeruginosa, we identified candidate virulence-blocking amychelin siderophore compounds from actinomycetes. Subsequently, we developed unreported analogs of these virulence-blocking siderophores with improved potency by exploiting an Amycolatopsis methanolica strain 239T chorismate to salicylate a biosynthetic subpathway for mutasynthesis. This allowed us to generate the fluorinated amychelin, fluoroamychelin I, which rescued C. elegans from P. aeruginosa-mediated killing with an EC50 value of 1.4 µM, outperforming traditional antibiotics including ceftazidime and meropenem. In general, this paper describes an efficient platform for the identification and production of classes of anti-microbial compounds with potential unique modes of action.

[Research progress on the regulation of phenolic compounds of traditional Chinese herbs on oral microbes].

Phenolic compounds are widely found in natural Chinese medicinal plants and have excellent pharmacological properties, such as antioxidation and anti-inflammation. They are the main pharmacological components of many medicinal Chinese herbs. Oral microbiota, especially its composition and metabolism, is highly related to the balance of oral microecology and plays a key role in the occurrence and development of oral diseases. Recent studies have shown that phenolic compounds of traditional Chinese herbs can prevent and treat oral diseases, such as caries, periodontal disease, and oral mucosal infection, by regulating the composition, metabolites, and virulence of oral microorganisms. This review will summarize and discuss the regulation of phenolic compounds on oral microbes.

Dimethylaminododecyl methacrylate inhibits Candida albicans and oropharyngeal candidiasis in a pH-dependent manner.

The prevalence of stomatitis, especially that caused by Candida albicans, has highlighted the need for new antifungal agents. We previously found that a type of quaternary ammonium salts, dimethylaminododecyl methacrylate (DMADDM), incorporated in dental materials inhibited the growth and hyphal development of C. albicans. However, how the quaternary ammonium salts inhibited the fungal pathogens and whether the oral condition, such as salivary pH variation under different diseases, can affect the antimicrobial capacity of quaternary ammonium salts is unknown. This study evaluated the antifungal effects of DMADDM at different pH in vitro and in vivo. A pH-dependent antifungal effect of DMADDM was observed in planktonic and biofilm growth. DMADDM enhanced antifungal activity at alkaline pH. Two pH-regulated genes (PHR1/PHR2) of C. albicans were correlated with the pH-dependent antifungal effects of DMADDM. The PHR1/PHR2 genes and pH values regulated the zeta potential of C. albicans, which then influenced the binding between C. albicans cells and DMADDM. The pH-dependent antifungal activity of DMADDM was then substantiated in a murine oropharyngeal candidiasis model. We directly demonstrated that the antifungal abilities of quaternary ammonium salts relied on the cell zeta potential which affected the binding between fungal cells and quaternary ammonium salts. These findings suggest a new antifungal mechanism of quaternary ammonium under different pH and that DMADDM can be a potential antifungal agent applied in dental materials and stomatitis therapy.Key Points • DMADDM has stronger antifungal activity in alkaline than in acidic pH conditions. • The pH values and pH-regulated genes can affect the zeta potential of fungal cells. • Zeta potential of fungal cells directly affect the binding between DMADDM and cells. Graphical abstract Schematic diagram of the antifungal activities of DMADDM at different pH values.

An analysis method for simultaneous screening of deoxyribonucleic acid-binding active compounds and investigating their mechanisms by ultra-fast liquid chromatography tandem mass spectrometry coupled with fluorescence detection technology.

DNA has been known as the cellular target for many cytotoxic anticancer agents over the years. Discovering DNA-binding compounds has become an active research area, while various DNA-binding mechanisms make the drug discovery even more difficult. In this article, we present a novel analysis method to rapidly identify specific DNA-binding compounds from Pyrrosia lingua (Thunb.) using DNA-dual-fluorescent probes, ethidium bromide and Hoechst 33258, with the technology of ultra-fast liquid chromatography-diode array detector-tandem mass spectrometry and dual-wavelength fluorescence detector (UFLC-DAD-MS(n)-DFLD). Sixty-two compounds were identified, of which 22 were found to be active in DNA-binding. After investigation of their dose-response behaviors and structure-activity relationships, chlorogenic acids and flavonoid glycosides were found to be DNA-binders via both minor groove-binding and intercalation modes. The precision, reproducibility and stability of this method were validated by vitexin. The established system was sensitive, precise, and reliable to be used for both screening of DNA-binding compounds and investigating of their mechanisms.

Arthrobacter liuii sp. nov., resuscitated from Xinjiang desert soil.

A Gram-stain positive, aerobic, non-motile actinobacterium, designated DSXY973(T), was isolated from soil samples collected from Xinjiang desert using medium supplemented with resuscitation-promoting factor, and subjected to a polyphasic taxonomic investigation. Phylogenetic analysis based on 16S rRNA gene sequences revealed that DSXY973(T) belonged to the genus Arthrobacter and was most closely related to Arthrobacter oryzae JCM 15922(T) with 97.1 % similarity. The DNA G+C content was 67.6 %. Cells of strain DSXY973(T) mainly contained MK-9(H2), and the cell wall contained l-lysine as the primary diamino acid. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C15 : 0. Strain DSXY973(T) was positive for catalase and negative for oxidase activity. On the basis of its phylogenetic position and phenotypic properties, strain DSXY973(T) represents a novel species of the genus Arthrobacter, for which the name Arthrobacter liuii sp. nov. is proposed. The type strain is DSXY973(T) ( = CGMCC1.12778(T) = JCM 19864(T)).

Endophytic Streptomyces sp. Y3111 from traditional Chinese medicine produced antitubercular pluramycins.

As part of a search for antitubercular substances from natural sources, we screened a library of endophytic microbes (50 strains and 300 crude extracts in total) isolated from traditional Chinese medicines (TCMs) for growth inhibitory activity against Bacillus Calmette-Guérin (BCG). The crude extract of Streptomyces sp. strain Y3111, which was associated with the stems of Heracleum souliei, showed good anti-BCG activity with an MIC value of 12.5 µg/mL. Bioassay-guided isolation led to four new pluramycin-type compounds, heraclemycins A-D (1-4). Their structures were determined by different spectroscopic techniques including HRMSESI, 1D NMR, and 2D NMR. This is the first report of pluramycin analogues produced by TCM endophytic microbes as well as the first example of BCG-selective pluramycins. Heraclemycin C (3) showed selective antitubercular activity against BCG with a MIC value of 6.25 µg/mL and a potential new mode of action.

On-line study of flavonoids of Trollius chinensis Bunge binding to DNA with ethidium bromide using a novel combination of chromatographic, mass spectrometric and fluorescence techniques.

The study of the interaction between drugs and DNA is an important way to understand the role of drug molecules. A novel online analytical method for this purpose combining high-performance liquid chromatography-diode array detector-electrospray ionization-ion-trap time-of-flight mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS(n)) and DNA-ethidium bromide detection with a fluorescence detector (DNA-EB-FLD) was firstly developed, which could rapidly identify the chemical constituents and obtain the profile related to DNA binding activity. This method has been applied for a precise or probable identification of the chemical constituents by ultraviolet (UV) absorption and MS(n) data analysis, while the DNA binding profile has been characterized by directly measuring the fluorescence intensity of compound-DNA-EB. Using this method, Trollius chinensis Bunge was studied and 18 constituents were identified by MS(n) data; six of them (4'-methoxy-2″-O-(2‴-methylbutyryl)vitexin,2″-O-(3‴-methoxycaffeoyl)vitexin) and 4'-methoxy-2″-O-(2‴-methylbutyryl)orientin,acacetin-7-O-rutinoside,quercetin-3-O-xylosylglucoside,quercetin-3-O-arabinosylglucoside) were identified for the first time in T. chinensis Bunge, and 16 constituents accounted for its activity of binding to DNA. The established (HPLC-DAD-ESI-IT-TOF-MS(n) DNA-EB-FLD) system has proved to offer a useful strategy for correlating the chemical profile with the binding to DNA activities of the components without their isolation and purification, and may be used for multicomponent analysis of active substances in other herbs.

Tricycloalternarenes F-H: three new mixed terpenoids produced by an endolichenic fungus Ulocladium sp. using OSMAC method.

Three new mixed terpenoids, tricycloalternarenes (TCAs) F-H (1-3), together with ten known tricycloalternarenes (4-13), were isolated from the Czapek's culture of an endophytic fungus Ulocladium sp. Their structures were identified by extensive spectroscopic experiments (NMR and MS) and comparison with literature data. TCA 1b (5) showed weak activity against the Bacille Calmette-Guerin strain with the MIC of 125µg/mL. TCA 9b (10) exhibited strong cytotoxic activity against Hela cell line with IC50 of 8.58µM.

Polyketides with antimicrobial activity from the solid culture of an endolichenic fungus Ulocladium sp.

Two new polyketides, 7-hydroxy-3, 5-dimethyl-isochromen-1-one (1) and 6-hydroxy-8-methoxy-3a-methyl-3a,9b-dihydro-3H-furo[3,2-c]isochromene-2,5-dione (2), along with eleven known compounds, 5'-methoxy-6-methyl-biphenyl-3,4,3'-triol (3), 7-hydroxy-3-(2-hydroxy-propyl)-5-methyl-isochromen-1-one (4), rubralactone (5), isoaltenuene (6), altenuene (7), dihydroaltenuenes A (8), altenusin (9), alterlactone (10), 6-O-methylnorlichexanthone (11), norlichexanthone (12), and griseoxanthone C (13) were isolated from the culture of the endolichenic fungus Ulocladium sp. Compound 2 was obtained as a racemate with an unprecedented chemical skeleton. The NMR data assignments for 3 and 4 were achieved for the first time. Compounds 1-13 were screened for their antimicrobial and radical scavenging activities. Compound 1 showed some antifungal activity against Candida albicans SC 5314 with IC(50) of 97.93 ± 1.12 µM. Compounds 11-13 showed strong activity against Bacillus subtilis with IC(50) in the range of 1-5 µM. Compound 12 significantly inhibited the growth of methicillin-resistant Staphylococcus aureus with IC(50) of 20.95 ± 1.56 µM. Compounds 9 and 10 showed strong radical scavenging activity in comparison with vitamin C. The plausible biosynthetic pathways for compounds 1, 2, and 4-8 were discussed.