Search

In our continuous work on the isolation of endophytes, the endophytic fungal strain YIMF00209 was obtained from the roots of Gmelina arborea , which is an ethnic medicinal plant mainly distributed in Southeast Asia. The fermentation extracts of the strain exhibited significant antimicrobial activities against Staphylococcus aureus , Fusarium solani , and Escherichia coli. Based on morphological characteristics and phylogenetic analysis, it was identified as Talaromyces muroii. Four new polyketides, talaromurolides A-D (1 – 4), along with 26 known compounds (5 – 30), were isolated from the culture broth of the strain in two different media. Their structures were identified based on HRESIMS, NMR, and CD spectral data. Among them, compounds 2 , 4 – 6 , 19 , 22 , 24 , 27 , 28 , and 30 were isolated from the fermentation broth in CYM medium; compounds 1 , 3 , 7 – 18 , 20 , 21 , 23 , 25 , 26 , and 29 were obtained from the fermentation broth in PDB medium; and compounds 2 , 5 , and 30 were existed in both two media. Compounds 6 – 9 , 12 , 16 , 20 , 21 , 23 , 25 , and 29 were obtained from the genus Talaromyces for the first time. The antimicrobial activities of several compounds were assayed against six pathogens. Compound 1 exhibited inhibitory activities against S. aureus , E. coli , Candida albicans , Salmonella typhimurium , and Botrytis cinerea with MIC value of 64 μg/mL. Compound 25 exhibited antibacterial activity against E. coli with MIC value of 32 μg/mL. [Display omitted] [ABSTRACT FROM AUTHOR]

Four previously unreported diterpenoids including three ent -atisanes (1–3) and one ent -abietane (4), along with one known linear triterpenoid (5) and five known diterpenoids including four myrsinanes (6–9), and one abietane (10) have been isolated from the roots of Euphorbia spinidens Bornm. ex Prokh. The structures were determined on the basis of extensive spectroscopic analyses including HR-ESI-MS, 1D and 2D NMR and comparison of the data with those reported in the literature. Antimicrobial potential of isolated compounds were also evaluated. Guionianol B (10) showed good antibacterial activity against Staphylococcus aureus and Bacillus subtilis with MIC value of 6.25 μg/mL. [Display omitted] [ABSTRACT FROM AUTHOR]

Two novel fungal polyketides, phometides A (1) and B (2), together with four known compounds (3–6), were isolated from the endophytic fungus Phoma sp. YUD17001 obtained from Gastrodia elata Blume. The structures were elucidated based on spectroscopic analyses, X-ray crystal diffraction, and time-dependent density functional theory/electronic circular dichroism (TDDFT/ECD) calculations. Structurally, phometide A (1) represented the first example of C 12 polyketide characterized by an unusual tetrahydrobenzofuran-3(2 H)-one core with an α , β -unsaturated ketone functionality, while phometide B (2) was an unprecedented molecule containing a 2-pentylcycloheptan-1-one scaffold. In an antimicrobial activity assay, phometide A (1) exhibited significant inhibitory activity against Staphylococcus aureus with MIC value of 4 μg/mL. Phometide B (2) showed moderate antifungal activity against Candida albicans with an MIC value of 16 μg/mL. Furthermore, compounds 1 and 2 were evaluated for their acetylcholinesterase inhibitory and cytotoxic activities. [Display omitted] • Two novel fungal polyketides were identified from the endophytic fungus Phoma sp. YUD17001. • Phometide A possess an unusual tetrahydrobenzofuran-3(2 H)-one functionality. • Phometide B is a novel polyketone containing a 2-pentylcycloheptan-1-one scaffold. • Phometides A and B demonstrated antimicrobial activity against S. aureus and C. albicans , respectively. [ABSTRACT FROM AUTHOR]

Three undescribed compounds (1 – 3), including two butenolides and one indol alkaloids. Together with twenty-one known compounds (4 – 24) were isolated and identified from Lepidium obtusum Basin. Their structures were elucidated by spectroscopic analysis and ECD calculations. The isolated compounds were tested for their antimicrobial, antioxidant, and anti-inflammatory activities. Among them, compounds 11 , 12 , 14 , 21 and 23 showed moderated antimicrobial activities against (Candida albicans , E. coli , Staphylococcus aureus). Compounds 11 , 12 , 14 , 15 , 17 and 18 exhibited potent antioxidant activities against ABTS and DPPH. Compound 1 exhibited moderated anti-inflammatory activities. Compounds 4 – 24 were isolated from this plant for the first time. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract A total of 180 fungal isolates, belonging to 20 genera and 47 species, were obtained from the roots, stems and leaves of Panax notoginseng. One isolate, the endophytic fungus Penicillium janthinellum SYPF 7899, displayed the strongest antibacterial activity and was studied for its production of secondary metabolites. In total, three new compounds, including rotational isomers 1a, 1b and 2 were isolated from the solid cultures of P. janthinellum , as well as eight known compounds (3 − 10). These structures were determined on the basis of 1D, 2D NMR and electronic circular dichroism (ECD) spectroscopic analyses as well as theoretical calculations. Compound 1 exhibited significant inhibitory activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 15 and 18 μg/ml, respectively. The other compounds showed moderate or weak activities. In addition, morphological observation showed the rod-shaped cells of B. subtilis growing into long filaments, which reached 1.5- to 2-fold of the length of the original cells after treatment with compound 1. The coccoid cells of S. aureus exhibited a similar response and swelled to a 2-fold volume after treatment with compound 1. In silico molecular docking was explored to study the binding interactions between the compounds and the active sites of filamentous temperature-sensitive protein Z (FtsZ) from B. subtilis and S. aureus. Compound 1a, 1b and 2 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ. Based on the antimicrobial activities, cellular phenotype observation and docking studies, compound 1 is considered to be a promising antimicrobial inhibitor of FtsZ. Graphical Abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Croton kongensis Gagnepain. belongs to the genus Croton , the Euphorbiaceae family, mainly distributed in Hainan and southern Yunnan, China. The aim of present study was to acquire secondary metabolites of the ethanol extract obtained from the leaves and twigs of C. kongensis. Three new abietane-type diterpenoids, crokongenolides A-C (1 – 3), together with seven known diterpenoids (4 – 10), were isolated from the leaves and twigs of C. kongensis. The structures of the new compounds were determined by extensive spectroscopic methods (1D and 2D NMR, IR, and HRESIMS), and their absolute configurations were confirmed by single-crystal X-ray diffraction analysis or electronic circular dichroism (ECD) calculations. The absolute configuration of 4 was determined for the first time by single-crystal X-ray diffraction analysis with Cu-Kα irradiation. Some compounds were evaluated for their antimicrobial properties by assessing their inhibitory effects on Staphylococcus aureus , Candida albicans , and Escherichia coli. Compound 10 showed significant antimicrobial activity against S. aureus with MIC value of 1.56 μg/ml. [Display omitted] • Three new abietane-type diterpenoids were isolated from the leaves and twigs of Croton kongensis. • The structures of three new compounds were elucidated by extensive analysis of spectroscopic data. • Some compounds showed significant antimicrobial activity against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Abstract: Propolis of Australian stingless bees (Tetragonula carbonaria, Meliponini) originating from Corymbia torelliana (Myrtaceae) fruit resins was tested for its antimicrobial activities as well as its flavonoid contents. This study aimed at the isolation, structural elucidation and antibacterial testing of flavanones of C. torelliana fruit resins that are incorporated into stingless bee propolis. Flavanones of this study were elucidated by spectroscopic and spectrometric methods including UV, 1D and 2D NMR, EI-MS, ESI-MS and HR-MS. The results indicated known C-methylated flavanones namely, 1 (2S)-cryptostrobin, its regioisomer 2 (2S)- stroboponin, 3 (2S)- cryptostrobin 7-methyl ether, and 6 (2S)- desmethoxymatteucinol, and known flavanones 4 (2S)- pinostrobin and 5 (2S)- pinocembrin as markers for C. torelliana fruit resins and one propolis type. Ethanolic preparations of propolis were shown to be active against Staphylococcus aureus (ATCC 25923) and to a lesser extent against Pseudomonas aeruginosa (ATCC 27853). C. torelliana flavanones inhibited the growth of S. aureus therefore contributing to the antibacterial effects observed for Australian stingless bee propolis extracts. [Copyright &y& Elsevier]

Abstract: Four new terpenoids, nemoralisins D–G (1–4), were isolated from the leaves and stems of Aphanamixis grandifolia, along with two known diterpenoids, nemoralisin C and nemoralisin. Among them, compound 1 is the first example of norsesquiterpenoid with δ-lactone moiety, and nemoralisins E–G (2–4), are a class of acyclic diterpenoids, which are structurally related nemoralisin C and nemoralisin. These structures were established on the basis of spectroscopic methods and the absolute configuration of 1 was determined by comparison of quantum chemical TDDFT calculated and experimental ECD spectra. Nemoralisins D–G (1–4) were tested for their cytotoxicities on HL-60, SMMC-7721, A-549, MCF-7, and SW480 human tumor cell lines (IC50 >40 μM), as well as the antimicrobial activities on Staphylococcus aureus, Pseudomonas aeruginosa, MRSA92# and MRSA98# (MIC>50 μg/mL). [Copyright &y& Elsevier]

Tabernaemontana corymbosa is a traditional folk medicine. In our research, six monoterpene indole N -oxide alkaloids and their parent alkaloids were obtained from the stem bark of T. corymbosa , including seven new alkaloids (1 – 7) and five known alkaloids (8 – 12). Their structures and absolute configurations were elucidated by extensive spectroscopy, quantum chemical calculations, and DP4+ probability analyses. The antimicrobial activity of the obtained compounds was evaluated, among which alkaloids 4 , 8 , 12 showed significant antimicrobial activity against Staphylococcus aureus with an MIC value of 6.25 μ g/mL, while alkaloids 11 , 12 showed moderate antimicrobial activity against Bacillus subtilis with an MIC value of 25 μ g/mL. [Display omitted] • Six N -oxide MIAs and their parent alkaloids were isolated from T. corymbosa. • Compounds 1 – 7 were identified to be new MIAs. • Alkaloid 1 was determined by quantum chemical calculations, and DP4+ analysis. • The antimicrobial activity of all MIAs was evaluated and discussed their differences. [ABSTRACT FROM AUTHOR]

Abstract: Telavancin was approved in the United States and Canada for the treatment of adult patients with complicated skin and skin-structure infections (cSSSI) caused by susceptible Gram-positive isolates. In this study, telavancin and comparator antimicrobial activities were determined against a total of 24 017 clinical isolates, including Staphylococcus aureus, coagulase-negative Staphylococcus spp. (CoNS), Enterococcus spp., and various Streptococcus spp. Overall, telavancin was highly active across all geographic regions for S. aureus (MIC50/90, 0.12/0.25 μg/mL; 100.0% susceptible), CoNS (MIC50/90, 0.12/0.25 μg/mL), vancomycin-susceptible Enterococcus faecalis (MIC50/90, 0.25/0.5 μg/mL; 100.0% susceptible), Enterococcus faecium (MIC50/90, 0.06/0.12 μg/mL), Streptococcus pneumoniae (MIC50/90, ≤0.015/0.03 μg/mL), viridans group Streptococcus spp. (MIC50/90, 0.03/0.06 μg/mL; 100.0% susceptible), and β-hemolytic Streptococcus spp. (MIC50/90, 0.03/0.12 μg/mL; 99.8% susceptible). Telavancin had potent activity against vancomycin-nonsusceptible, teicoplanin-susceptible (VanB) E. faecalis (MIC50/90, 0.25/0.5 μg/mL) and E. faecium (MIC50/90, 0.06/0.25 μg/mL). These in vitro results show continued activity for telavancin, which represents an important alternative available for treating cSSSI. [Copyright &y& Elsevier]

Abstract: HKABF, Hippocampus kuda antibacterial factor, is a putative antimicrobial peptide identified from the cDNA library of the brooding pouch of H. kuda Bleeker. The putative mature peptide, fused with a 6His-tag, an anionic peptide (SAPLNPDNID) and to an enterokinase cleavage site was expressed in Pichia pastoris. The mature HKABF peptide, released by enterokinase cleavage, showed antimicrobial activity against Staphylococcus aureus and Staphylococcus saprophyticus at low concentrations (0.5–2.5μg/ml). The recombinant mature peptide was heat-stable and had low hemolytic activity. Circular dichroism (CD) spectroscopy data indicates its classification as a CSαβ-type antimicrobial peptide. This study serves as an impetus for the production and further research of this antimicrobial peptide. [Copyright &y& Elsevier]

Abstract: Two new chamigrane-type metabolites named steperoxides C (1) and D (2) were isolated from the basidiomycetes Steccherinum ochraceum. The structures of 1 and 2 were established on the basis of spectral methods (MS, IR, ID and 2D NMR experiments). Compounds 2 showed significant antimicrobial activity against Staphylococcus aureus at 10 and 5μg/disk. [Copyright &y& Elsevier]