PhD Scientific Days 2023

Pharmaceutical Sciences - Posters F

Antimicrobial Potential of Two Diterpenes Isolated from Rough Goldenrod (Solidago rugosa Mill.) against Plant Pathogens

Text of the abstract

Introduction: Plants are considered an inexhaustible source of secondary metabolites possessing diverse structures and valuable biological activity. Rough goldenrod (Solidago rugosa Mill.) is a plant being indigenous in America and naturalized as an alien in certain regions of Europe. Nevertheless, its bioactive natural products have been poorly studied.
Aims: This work aimed to detect, isolate, and identify the antimicrobial constituents of the ethanolic extract of S. rugosa roots and leaves. Their in vitro antimicrobial effects were also investigated against various Gram-positive (Bacillus spizizenii, Clavibacter michiganensis subsp. michiganensis, Curtobacterium flaccumfaciens pv. flaccumfaciens) and Gram-negative (Xanthomonas arboricola pv. pruni) bacterial as well as fungal (Bipolaris sorokiniana, Fusarium avenaceum) strains including phytopathogenic organisms.
Methods: Non-targeted, effect-directed screening for antimicrobial components were carried out by high-performance thin-layer chromatography coupled with direct bioautography (HPTLC–DB). Fractionation and isolation were performed by preparative flash column chromatography. The structures of the isolates were elucidated by one- and two-dimensional nuclear magnetic resonance spectroscopy (NMR), high-resolution tandem mass spectrometry (HRMS/MS) and polarimetry. Half-maximal inhibitory concentration (IC50) values were obtained from in vitro microdilution assays.
Results: Two compounds were detected and isolated from S. rugosa identified as (–)-hardwickiic acid (1) and (–)-abietic acid (2). This is the first report about the presence and abundance of 2 in S. rugosa. 1 and 2 exhibited strong inhibitory activity (IC50 = 1.0–5.1 µg/ml) against all studied Gram-positive bacteria. However, only weak antibacterial effect (IC50 = 201.2 and 166.6 µg/ml) was observed against the Gram-negative X. arboricola pv. pruni for 1 and 2, respectively. 1 significantly inhibited the growth of B. sorokiniana with an IC50 of 3.8 µg/ml, and demonstrated moderate antifungal activity (IC50 = 73.5 µg/ml) against F. avenaceum. 2 appeared less potent against the examined fungal strains (IC50 = 165.5 and 120.6 µg/ml, respectively).
Conclusions: After the antimicrobial activity enhancement of 1 and 2 by suitable synthetic modifications and formulations they can become more potent biopesticides.
Funding: This study was supported by the National Research, Development and Innovation Office of Hungary (K128921 and SNN139496).
-----------------------------------------------------------------------------------------------------------
E-mail: baglyas.marton@phd.semmelweis.hu
Doctoral School and University: Doctoral School of Pharmaceutical Sciences, Semmelweis University
Supervisor: Ágnes M. Móricz (correspondence: moricz.agnes@atk.hu)
The study is preferred to be presented as a poster.