# A double agent? Unveiling the chemical profile of the pathogenic fungus Pyrrhoderma noxium as an endophyte in true mangroves

## TL;DR

A fungus known for causing root rot was found in mangrove leaves and produces bioactive compounds with potential medical uses.

## Contribution

This is the first report of Pyrrhoderma noxium as an endophyte and its chemical profiling for bioactive compounds.

## Key findings

- Three P. noxium isolates were identified and chemically profiled using LC-MS/MS.
- The isolates produced compounds with potential pharmaceutical applications like anticancer and antioxidant properties.
- AA2AA and SA2AA isolates showed greater similarity compared to BG3BA based on chemical profiles.

## Abstract

Pyrrhoderma noxium, commonly referred to as the brown root rot pathogen, has previously been recognized as a pathogenic species. However, it has been largely overlooked for its capability to produce useful bioactive compounds. In this study, we report for the first time that the fungus has been isolated as an endophytic fungus (EF) from the leaves of true mangrove plant species, and chemically profiled the fungal isolates to identify potential bioactive compounds. Three P. noxium isolates (AA2AA, BG3BA and SA2AA) were successfully identified via DNA barcoding and were subjected to methanolic extraction prior to chemical profiling via liquid chromatography-tandem mass spectrometry (LC-MS/MS). Despite proximity of the host plants, our results, comprising morphological characteristics, phylogenetic analysis, and the Jaccard Similarity Index based on the detected compounds showed that AA2AA and SA2AA possess greater similarity compared to any of them with BG3BA. Compounds produced by the P. noxium isolates were classified into six main classes (i.e., amino acids and peptides, aromatics, terpenoids, phenolics, other lipids, and other alkaloids) and these compounds are believed to facilitate the equilibrium in endophyte-host interactions. According to literature, the identified compounds from the P. noxium isolates have previously been reported to possess anticancer, antioxidant, anti-inflammatory, antibacterial, antifungal, and antiviral activities, indicating significant potential for pharmaceutical applications. Besides, the chemical profiles of the P. noxium isolates determined in this study may serve as a reference for subsequent research on the biological control of P. noxium infection.