Secondary Metabolites and Antifungal Activity of the Endophytic Fungus Streptomyces humidus SCB0232 from Water Chestnut

Chemistry of Natural Compounds - A new macrolide, named concanamycin H (1), together with 12 known compounds (2–13), was isolated from the endophytic Streptomyces humidus SCB0232 for the...     

Two New 23‐Membered Macrolactones from a Terrestrial Bacterium,Streptomyces sp. IMBJ01

Two new unusual 23‐membered macrolactones, named griseoviridins B ( 1 ) and C ( 2 ), along with the known analogue griseoviridin ( 3 ) were isolated from the culture of Streptomyces sp. IMBJ01, a terrestrial bacterium isolated from Wolong, Sichuan Province, China. The structures of 1 and 2 were elucidated on the basis of extensive spectroscopic data and their absolute configurations were determined by comparison of their CD spectra with those of compound 3 .     

Secondary metabolites from marine-derived Streptomyces antibioticus strain H74-21

A new secondary metabolite, (2S,3R)-l-threonine, N-[3-(formylamino)-2-hydroxybenzoyl]-ethyl ester (streptomyceamide C, 1), together with four known compounds 1, 4-dimethyl-3-isopropyl-2,5-piperidinedione (2), cyclo-((S)-Pro-8- hydroxy-(R)-Ile (3), cyclo-((S)-Pro-(R)-Leu (4), and seco-((S)-Pro-(R)-Val) (5), were isolated from the EtOH extract of the fermented mycelium of the marine-derived streptomycete strain H74-21, which was isolated from sea sediment in a mangrove site. The structure of the new compound was established on the basis of its spectroscopic data, including 1D and 2D NMR, HR-TOF-MS. Their antifungal activities against Candida albicans and cytotoxicities against human breast adenocarcinoma cell line MCF-7, human glioblastoma cell line SF-268 and human lung cancer cell line NCI-H460 were tested. Compounds 1 only displayed cytotoxicity against human breast adenocarcinoma cell line MCF-7 with the IC₅₀ value of 27.0 μg/mL. However, compounds 1–5 do not show antifungal activities at the test concentration of 1 mg/mL, and 2–5 have no cytotoxicities at the test concentration of 50 μg/mL.     

New Kendomycin Derivative Isolated from Streptomyces sp. Cl 58-27

In the course of screening new streptomycete strains, the strain Streptomyces sp. Cl 58-27 caught our attention due to its interesting secondary metabolite production profile. Here, we report the isolation and characterization of an ansamycin natural product that belongs structurally to the already known kendomycins. The structure of the new kendomycin E was elucidated using NMR spectroscopy, and the corresponding biosynthetic gene cluster was identified by sequencing the genome of Streptomyces sp. Cl 58-27 and conducting a detailed analysis of secondary metabolism gene clusters using bioinformatic tools.     

Antifungal metabolites from Blumea balsamifera

The leaves of Blumea balsamifera afforded icthyothereol acetate, cryptomeridiol, lutein, and beta-carotene. The structures of icthyothereol acetate (1) and cryptomeridiol (2) were elucidated by extensive 1D and 2D NMR spectroscopy, while those of lutein and beta-carotene were identified by comparison with literature data. Antimicrobial tests indicated that 1 has moderate activity against the fungi Aspergillus niger, Trichophyton mentagrophytes, and Candida albicans, while 2 has low activity against A. niger, T. mentagrophytes, and C. albicans. Both compounds have no antimicrobial activity against Psuedomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, and Escherichia coli.     

Antifungal cyclopentenediones from Piper coruscans

Coruscanones A and B, two new antifungal cyclopentenedione derivatives, have been isolated from Piper coruscans and their structures elucidated by spectroscopic and chemical methods. Coruscanone A exhibits significant antifungal activity against Candida albicans and its azole-resistant strains and may serve as a template for a new class of antifungal agents.     

Biogenic Synthesis of Silver Nanoparticles Using Streptomyces spp. and their Antifungal Activity Against Fusarium verticillioides

The present study reports the synthesis of silver nanoparticles (AgNPs) using haloalkaliphilic Streptomyces spp. characterization, and antifungal activity thereof. The UV visible spectra of synthesized AgNPs showed a characteristic absorption peak at 430 nm, due to the excitation of Surface Plasmon Resonance. Scanning electron microscopy and transmission electron microscopy images showed spherical shape NPs with an average particle size of 16.4?±?2.2 nm. The crystalline structure of the AgNPs was confirmed by X-ray diffraction (XRD). Zeta potential analyses revealed that NPs were negatively charged (??8.12?±?3.87 mV). The synthesized AgNPs are significantly active against phytopathogenic fungi, Fusarium verticillioides and Ustilago maydis. Microscopic, histo- and bio-chemical investigation of AgNPs against F. verticillioides revealed that AgNPs at 100 μg concentration inhibits the hyphal growth and conidia germination, and?~?42.85% reduction of ergosterol biosynthesis. The results of propidium iodide staining and high relative cell membrane conductivity confirmed AgNPs mediated damage to the membrane. Moreover, the AgNPs synthesized by Streptomyces spp. inhibit the growth of F. verticillioides could be due to the inhibition of ergosterol biosynthesis and membrane damage. In our knowledge, this is the first report demonstrating the anti F. verticillioides activity of AgNPs synthesized by Streptomyces spp.

     

A New Carotane Sesquiterpenoid Derivative with Antifungal Activity from Gymnopus sp. 0612-9

Chemistry of Natural Compounds - A new carotane sesquiterpenoid, methyl gymnabloate (1), was isolated from the fermentation broth of the wild macrofungus Gymnopus sp. 0612-9. Its structure was...     

Lactoquinomycin C and D,two new medermycin derivatives from the marine-derived Streptomyces sp. SS17A

Abstract

Lactoquinomycin C (1) and Lactoquinomycin D (2), two new medermycin derivatives together with six known compounds (3–8) were isolated from the rice solid fermentation of the marine-derived Streptomyces sp. SS17A. The intriguing structural features of the Lactoquinomycin D (2) which contains 5,14-epoxidation is relatively rare in medermycin derivatives. Compounds 1 and 2 exhibited no cytotoxicity against PC-3 and HCT-116 cancer cell lines, whereas compound 3 showed stronger cytotoxicity with IC₅₀ values of 0.02 and 0.04?μM, respectively. A structure-activity relationship was observed for the cytotoxicity of the medermycin derivatives with a γ-lactone unit is required for significant cytotoxicity based on compounds 1–3.     

Antifungal activity from 14-helical beta-peptides

We have discovered that short beta-peptides (9 or 10 residues) designed to adopt globally amphiphilic helical conformations display significant antifungal activity. The most promising beta-peptides cause little lysis of human red blood cells at concentrations that kill Candida albicans, a common human fungal pathogen. Since fungi are eukaryotes, discrimination between fungal and human cells is a significant finding. Our beta-peptides are active under assay conditions that mimic physiological ionic strength; in contrast, alpha-helix-forming host-defense alpha-peptides are inactive against C. albicans under these conditions.     

New carbasugars from Streptomyces lincolnensis

Two new carbasugars (9 and 10) were isolated from Streptomyces lincolnensis DSM 40355 along with streptol (valienol, 8), gabosine I (valienone, 14), and glucosylglycerate. The reported ¹H and ¹³C assignments are based on 1D (¹H, ¹³C, 1D‐TOCSY, homodecoupling) and 2D (gCOSY, J‐resolved, TOCSY, ROESY, gHSQC, gHMBC) NMR techniques and electrospray ionization FT mass spectrometry (ESI FTMS). Copyright © 2009 John Wiley & Sons, Ltd.     

从细脚拟青霉分离的新环二肽与新十元环内酯

利用反相色谱、 凝胶色谱和硅胶色谱从细脚拟青霉发酵液中分离得到4个活性化合物. 通过核磁共振波谱、 质谱、 X射线晶体衍射分析和理化数据鉴定化合物1为新环二肽[(3S)-6-苯乙基-3-异丙基-1-甲基-2,5-二酮哌嗪], 化合物2为新十元环内酯[(4S,10R)-4-羟基-8-氧代-10-甲基癸内酯], 化合物3为Cepharosporolide C, 化合物4为Cepharosporolide E. 细胞毒性实验结果表明, 5 μmol/L的化合物1对前列腺癌细胞22RV1和DU-145的抑制率分别为37.8%和38.6%, 5 μmol/L的化合物2对前列腺癌细胞22RV1和DU-145的抑制率分别为32.5%和40.6%, 具有一定抗肿瘤活性.     

Cyclic Peptide Secondary Metabolites with Antifungal Activity Against Root-Rot Pathogens of Panax notoginseng Produced by Streptomyces yatensis

Chemistry of Natural Compounds -     

Purification and structure elucidation of three naturally bioactive molecules from the new terrestrial Streptomyces sp. TN17 strain

Thirty litres of fermentation broth was extracted from the newly isolated Streptomyces sp. strain TN17 and various separation and purification steps led to the isolation of three pure bioactive compounds (1-3). Compound 1: cyclo (L-Leu-L-Arg), a diketopiperazine 'DKP' derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; and 3: cyclo 1-[2-(cyclopentanecarbonyl-3-phenyl-propionyl]-pyrrolidine-2-carboxylic acid (1-carbamoyl-propyl)-amide, a cyclic tetrapeptide derivative. The chemical structure of these three active compounds was established on the basis of spectroscopic studies (MS and NMR) and by comparison with data from the literature. According to our biological studies, the pure compounds (1-3) possess antibacterial and antifungal activities.