3 years ago

Decalin-Containing Tetramic Acids and 4-Hydroxy-2-pyridones with Antimicrobial and Cytotoxic Activity from the Fungus Coniochaeta cephalothecoides Collected in Tibetan Plateau (Medog)

Decalin-Containing Tetramic Acids and 4-Hydroxy-2-pyridones with Antimicrobial and Cytotoxic Activity from the Fungus Coniochaeta cephalothecoides Collected in Tibetan Plateau (Medog)
Hongwei Liu, Yanfen Xue, Qian Chen, Hui Zhou, Junjie Han, Congcong Liu, Cheng Jin, Fuhang Song, Yunfei Pei, Li Li, Lixin Zhang, Li Liu, Yanhe Ma, Wenbing Yin, Erwei Li, Ling Liu, Li Bao
New tetramic acid derivatives, (±)-conipyridoins A–D (14), conipyridoins E (5) and F (6), and new 4-hydroxy-2-pyridone alkaloids (±)-didymellamide E (7), (+)-didymellamide B (8), (+)-N-hydroxyapiosporamide (9), and didymellamides F–H (1012) were isolated and identified from the solid culture of the fungus Coniochaeta cephalothecoides. Chiral resolution of 1, 2, 3, 4, and 7 gave five pairs of enantiomers: 1a/1b, 2a/2b, 3a/3b, 4a/4b, and 7a/7b, respectively. Stereochemistry of 1a and 1b, and 2a and 2b was established and confirmed by the single-crystal X-ray diffraction and electronic circular dichroism (ECD) methods. Absolute configuration in 3a, 3b, 4a, 4b, 7a, and 7b was assigned by ECD calculations. Compounds 16 possess an unprecedented chemical skeleton featuring a decalin ring and a tetramic acid moiety. Compound 11 significantly inhibited the growth of Candida albicans and Aspergillus fumigatus with minimum inhibitory concentration (MIC) of 3.13 and 1.56 μM, respectively, and was further confirmed to be a new chitin synthesis inhibitor. Compound 5 exhibited the strongest activity against the growth of both Staphylococcus aureus and MRSA with MIC value of 0.97 μM. In the light of a co-occurrence of 3-acyl tetramic acids and biogenetically related pyridine alkaloids, the biosynthetic pathway for 112 was postulated.

Publisher URL: http://dx.doi.org/10.1021/acs.joc.7b02010

DOI: 10.1021/acs.joc.7b02010

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.