Antimalarial 20-membered macrolides from Streptomyces sp. BCC33756

Two new natural products, samroiyotmycins A (1) and B (2), along with two naturally new novclobiocin 101 (3) and 4-hydroxy-3-(3-methylbut-2-enyl)benzamide (5), and five known substances including neoantimycin, clorobiocin (4), 29-O-methylabierixin, daidzein, and 1-(3-indolyl)-2,3-dihydroxypropan-1-one have been isolated from Streptomyces sp. BCC33756. Their chemical structures were determined based on NMR spectral information and the relative stereochemistry of compound 1 was determined by X-ray crystallographic data. Both samroiyotmycins A and B exhibited antimalarial activity against Plasmodium falciparum K1—multi-drug resistant strain, with IC₅₀ values of 3.65 and 3.16 μg/mL, respectively. Compound 1 was inactive against both cancerous (MCF-7, KB) and non-cancerous (Vero) cells, while compound 2 displayed cytotoxicity against Vero cell with IC₅₀ value of 29.57 μg/mL.     

Salicylaldehyde and dihydroisobenzofuran derivatives from the marine fungus Zopfiella marina

Two salicylaldehyde derivatives (1 and 2), a hydroxymethylphenol (3), five dihydroisobenzofuran (4–8) derivatives, and a 5-chloro-3-deoxyisoochracinic acid (9), together with a known 3-deoxyisoochracinic acid (10) were isolated from the marine fungus Zopfiella marina BCC 18240 (or NBRC 30420). The structures of these compounds were elucidated by extensive spectroscopic analysis. Compound 1 showed weak antituberculous activity against Mycobacterium tuberculosis H37Ra, and antibacterial activity against Bacillus cereus with MIC values of 25 and 12.5 μg/mL, respectively.     

Highly Conjugated Ergostane‐Type Steroids and Aranotin‐Type Diketopiperazines from the Fungus Aspergillus terreus BCC 4651

Two new ergostane derivatives, 12β,15α,25,26‐tetrahydroxyergosta‐4,6,8(14),22‐tetraen‐3‐one ( 1 ) and 12β,15α,25,28‐tetrahydroxyergosta‐4,6,8(14),22‐tetraen‐3‐one ( 2 ), and a new aranotin‐type diketopiperazine, bisdethiobis(methylsulfanyl)apoaranotin ( 3 ), were isolated from the fungus Aspergillus terreus BCC 4651. The structures of the new compounds were elucidated by means of NMR spectroscopic and MS analyses.     

Antimicrobial activity of cyathane derivatives from Cyathus subglobisporus BCC44381

Six unknown cyathane diterpenes, named cyathinins A – E, and 10-hydroxyerinacine S, were isolated from Cyathus subglobisporus BCC44381 along with six known compounds, striatoid C, striatin C, striatals A, C, D, and glochidone. The chemical structures were determined by means of high resolution mass spectrometry (HRESI-MS) and nuclear magnetic resonance (NMR) spectroscopy. The absolute configurations were confirmed by X-ray diffraction analysis. The isolated active compounds exhibited antimalarial against Plasmodium falciparum (IC₅₀ 0.88–7.51?μM), antibacterial activities against Mycobacterium tuberculosis (MIC 25–50?μg/mL), Gram-positive bacteria of Bacillus cereus and Enterococcus faecium (MIC 0.78–50?μg/mL) and Gram-negative bacteria of Escherichia coli, Acinetobacter baumannii and Klebsiella pneumoniae in a presence of phenylalanine-arginine β-naphthylamide (MIC 3.13–50?μg/mL), antifungal activity against Candida albicans (IC₅₀ 8.6–80.3?μM) activities, and cytotoxic activity against both cancerous (MCF-7, KB, NCI-H187, IC₅₀ 0.36–28.32?μM) and non-cancerous (Vero, IC₅₀ 0.13–91.50?μM) cells.