Phytotoxic activity of umbelliferone derivatives produced by microbial transformation

Authors: RIBEIRO, VICTOR - ARS Postdoctoral Research Associate; Meepagala, Kumudini; Bajsa Hirschel, Joanna

Submitted to: ACS Agricultural Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2026
Publication Date: 2/4/2026
Citation: Ribeiro, V.P., Meepagala, K.M., Bajsa Hirschel, J.N. 2026. Phytotoxic activity of umbelliferone derivatives produced by microbial transformation. ACS Agricultural Science and Technology. Article ASAP. https://doi.org/10.1021/acsagscitech.5c00812.
DOI: https://doi.org/10.1021/acsagscitech.5c00812

Interpretive Summary: This study looked for new natural alternatives to chemical herbicides, which can harm the environment and are losing effectiveness due to resistant weeds. Researchers used two types of fungi to transform umbelliferone, a plant compound found in many herbs, into new versions. They tested all the compounds on two types of plants—one grass and one broadleaf—to see if they could stop seed growth. One of the new compounds stood out by completely stopping the seeds from sprouting. This shows that fungi can help create natural substances with strong weed-killing potential.

Technical Abstract: The search for natural herbicide alternatives is increasingly relevant in the context of environmental concerns and herbicide-resistant weeds. In this study, umbelliferone, a 7-hydroxycoumarin widely found in plants, particularly in Rutaceae and Apiaceae was subjected to microbial biotransformation using Cunninghamella elegans and Aspergillus brasiliensis under two different culture conditions. Five structurally distinct derivatives were produced during fermentation. The structures were elucidated by 1D and 2D NMR spectroscopy and confirmed by high-resolution mass spectrometry. All compounds, including the precursor, were evaluated for phytotoxic activity against Lactuca sativa (dicot) and Agrostis stolonifera (monocot). Compound 6 exhibited the strongest inhibition, completely preventing seed germination in both species. In silico prediction of physicochemical properties using SwissADME indicated that lipophilicity, hydrogen bonding potential, and polar surface area may contribute to the observed biological effects. These findings show the potential of microbial systems to diversify natural scaffolds and support their application in the development of novel plant-derived bioherbicides.