Antifungal and Phytotoxic activities of isolated compounds from Helietta parvifolia stems

Authors: RIBEIRO, VICTOR - Oak Ridge Institute For Science And Education (ORISE); Bajsa-Hirschel, Joanna; Tamang, Prabin; Meepagala, Kumudini; DUKE, STEPHEN - University Of Mississippi

Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2023
Publication Date: 12/4/2023
Citation: Ribeiro, V., Bajsa Hirschel, J.N., Tamang, P., Meepagala, K.M., Duke, S. 2023. Antifungal and phytotoxic activities of isolated compounds from Helietta parvifolia stems. Molecules. 28(23):7930. https://doi.org/10.3390/molecules28237930.
DOI: https://doi.org/10.3390/molecules28237930

Interpretive Summary: Helietta parvifolia, commonly known as Baretta, is a perennial flowering tree belonging to the Rutaceae family. Members of the Rutaceae family are renowned for producing a wide range of compounds, many of which exhibit diverse biological activities, including antifungal and herbicidal. H. parvifolia is native to the Lower Rio Grande Valley of Texas and northeastern Mexico. In our efforts to search for environmentally friendly agrochemicals, we investigated the extracts of this plant. We were able to identify and isolate herbicidal and fungitoxic constituents from the extracts of the stems of Helietta parvifolia and we identified eight compounds, consisting of two coumarins and six alkaloids. A new alkaloid is reported here for the first time. Our findings indicate that the Rutaceae family of plants produces compounds that are useful in searching for novel pesticides.

Technical Abstract: The identification of natural and environmentally friendly pesticides is a key area of interest for the agrochemical industry, with many potentially active compounds being sourced from numerous plant species. In this study, we report the bioassay-guided isolation and identification of phytotoxic and antifungal compounds from the ethyl acetate extract of Helietta parvifolia stems. We identified eight compounds, consisting of two coumarins and six alkaloids. Among these, a new alkaloid, 2-hydroxy-3,6,7-trimethoxyquinoline-4-carbaldehyde (6), was elucidated, along with seven known compounds. The phytotoxicity of purified compounds was evaluated, and chalepin (4) was active against Agrostis stolonifera at 1 mM and reduced Lemna pausicotata (duckweed) by 50% (IC50) at 168 µM. Additionally, we evaluated the antifungal activity against the fungal plant pathogen Colletotrichum fragariae using a thin-layer chromatography bioautography assay, which revealed that three isolated furoquinoline alkaloids had strong inhibitory effects on the growth of C. fragariae at all tested concentrations.