# Eight new α-pyrone and γ-butenolide derivatives from the plant endophytic fungus Diaporthe sp. CCY4

## TL;DR

Researchers discovered eight new chemical compounds from a plant fungus and found some inhibit a key enzyme involved in protein regulation.

## Contribution

The paper reports the isolation and characterization of eight new α-pyrone and γ-butenolide derivatives from an endophytic fungus.

## Key findings

- Eight new compounds were isolated and structurally identified using advanced spectroscopic methods.
- Four compounds showed significant anti-ubiquitination activity against USP4, with one being particularly potent.
- The study highlights the potential of fungal metabolites as sources of bioactive compounds.

## Abstract

Five new α-pyrones, diaporpyrones G-K (1–5) and three new γ-butenolide derivatives, porbutenolides A-C (6–8), along with seven known compounds (9–15), were isolated from the culture extract of the endophytic fungus Diaporthe sp. CCY4. Their structures were elucidated by comprehensive spectroscopic analysis, including 1D/2D NMR and HRESIMS data. The absolute configurations of 7 and 8 were assigned using electronic circular dichroism (ECD) calculations. All compounds were evaluated for inhibitory activity against ubiquitin-specific peptidase 4 (USP4). Compounds 2, 5, 9, and 13 exhibited significant anti-ubiquitination effects at 40 μM, with 13 showing the most potent inhibition (IC50 = 20.85 μM).

The online version contains supplementary material available at 10.1007/s13659-025-00580-1.