# Minutellins E-I and daldinone L, new secondary metabolites from different species of the Hypoxylaceae (Xylariales, Ascomycota)

## TL;DR

This study identifies new secondary metabolites from fungi in the Hypoxylaceae family and corrects a previous chemical structure misassignment.

## Contribution

Discovery of a new daldinone derivative and five new minutellin-type azaphilones, along with a structural correction of daldinone A.

## Key findings

- A new daldinone derivative and five new minutellin-type azaphilones were identified from Hypoxylaceae fungi.
- Daldinone A was found to have been misassigned and is actually daldinone C.
- The distribution of minutellin-type azaphilones across the Hypoxylaceae family was discussed.

## Abstract

Fungi of the family Hypoxylaceae (Xylariales, Ascomycota) are ubiquitously distributed and fulfil important ecological roles as saprobes, pathogens, and endophytes. Members of this family tend to store large amounts of secondary metabolites in their carbonaceous stromatal tissue commonly formed on colonised wood. This feature is of both taxonomic and chemical value by serving as chemotaxonomic markers and sources of potential new and bioactive compounds. Despite tremendous progress in the characterisation of Hypoxylaceae both in terms of genomics and secondary metabolomics, many unknown metabolites remain to be identified or elucidated. Here, we report on the polyphasic, i.e. morphological, chemical, and genetical analysis of Hypoxylon and Annulohypoxylon spp. collected from the Iranian shore of the Caspian Sea and a chemotaxonomic study of the constituents of a concurrently studied specimen of A. michelianum. A new daldinone derivative and five new minutellin-type azaphilones from stromatal tissues of A. substygium and H. lateripigmentum, respectively, were identified in the course of this study by high-performance liquid chromatography/mass spectrometry coupling (HPLC-MS) and structurally elucidated by nuclear magnetic resonance (NMR) spectroscopy. We realised that the structure of daldinone A was misassigned and in fact equals daldinone C. Finally yet importantly, the distribution of minutellin-type azaphilones throughout the Hypoxylaceae is discussed.