Cytotoxic, antimicrobial and antiviral secondary metabolites produced by the plant pathogenic fungus Cytospora sp. CCTU A309

Abstract

Chemical analysis of extracts from cultures of the plant pathogenic fungus Cytospora sp. strain CCTU A309 collected in Iran led to the isolation of two previously unreported heptanedioic acid derivatives namely (2R,3S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (1) and (2S,3S) 2-hydroxy-3-phenyl-4-oxoheptanedioic acid (2) as diastereomers, four previously undescribed prenylated p-terphenyl quinones 3-6 in addition to five known metabolites. Their structures were elucidated on the basis of extensive spectroscopic analysis and highresolution mass spectrometry. While the relative configurations of 1 and 2 were reasoned by a J-based analysis and confirmed by comparison of 13 C chemical shifts to literature data, their absolute configurations were deduced from comparison of the 1 H NMR difference of their (S)-and (R)-phenylglycine methyl ester derivatives. The isolated compounds were tested for their cytotoxic, antimicrobial, biofilm inhibition, antiviral, and nematicidal activities. While only moderate antimicrobial effects were observed, the terphenyl quinone derivatives 3-6 and leucomelone (10) exhibited significant cytotoxicity against the mouse fibroblast L929 and cervix carcinoma KB-3-1 cell lines with IC 50 values ranging from 2.4 to 26 µg/mL. Furthermore, metabolites 4-6 showed interesting antiviral activity against hepatitis C virus (HCV).

Cytotoxic Compounds from the Stem Bark of Two subsp. of Bersama abyssinica

“…Compound 6 showed MIC values of 158.0 μM against both B. subtilis and S. aureus . In previous work, a quinone-like compound showed weak antibacterial activities against B. subtilis with MIC values ranging from 157 to 170 μM . This MIC range is similar to that exhibited by 6 in this study.…”

“…In previous work, a quinone-like compound showed weak antibacterial activities against B. subtilis with MIC values ranging from 157 to 170 μM. 21 This MIC range is similar to that exhibited by 6 in this study. Furthermore, 6 showed weak antibacterial activity against Gram-negative S. aureus.…”

p-Terphenyl alcohols from a marine sponge-derived fungus, Aspergillus candidus OUCMDZ-1051

“…The structural diversity of the natural p-terphenyls mainly resulted from the variation of the ring B, the number and the position of hydroxy groups, and the changes of the phenol to quinone functions. Approximately 230 natural p-terphenyls have been identified from the year 1877 to 2018 (Li et al 2018;Liu 2006), and this number is growing every year (Kalansuriya et al 2019;Kalvo et al 2018;Lin et al 2019;Lu et al 2019;Narmani et al 2019;Ren et al 2018;Sangsopha et al 2019;Song et al 2019;Wang et al 2019b;Xu et al 2018). Our present work isolated and identified a new p-terphenyl alcohol with a dibenzofuran moiety from the marine sponge-derived fungus A. candidus OUCMDZ-1051, as well as nine known p-terphenyl alcohols.…”

Five Tetramic Acid Derivatives Isolated from the Iranian Fungus Colpoma quercinum CCTU A372

“…During our routine screening program for novel anti-infective from endophytic fungi, in August 2016, apparently healthy and symptomless 2–3 year old shoots were collected from willow ( Salix sp.) in Kaleybar region in northwestern Iran, and fungal endophytes were obtained according to previously described protocols [ 11 ]. In brief, 10–20 cm length shoots were surface-sterilized for 45–60 s in 70% ethanol, then 10 min in 3% sodium hypochloride (NaClO), and 30 s in 70% ethanol.…”