Evaluation of the Antibacterial Effect of Cymbopogon citratus and Pelargonium graveolens Essential Oils on the Growth of the Pathogenic Bacteria Pectobacterium carotovorum and Pantoea stewartii

Mirzaei Najafgholi, Hosein; Hasanvand, Ehsan; Poshtdar, Adel; Rohani, Neda

doi:10.22059/ijhst.2025.380662.905

Evaluation of the Antibacterial Effect of Cymbopogon citratus and Pelargonium graveolens Essential Oils on the Growth of the Pathogenic Bacteria Pectobacterium carotovorum and Pantoea stewartii

Document Type : Research paper

Authors

Hosein Mirzaei Najafgholi ¹

Ehsan Hasanvand ¹

Adel Poshtdar ²

Neda Rohani ¹

¹ Plant Protection Department, Faculty of Agriculture, Lorestan University, Khoramabad, Iran

² Department of Plant Production and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Khuzestan, Iran

10.22059/ijhst.2025.380662.905

Abstract

Pectobacterium carotovorum and Pantoea stewartii are bacterial pathogens. Essential oils derived from medicinal plants have shown potential in inhibiting the growth of these plant bacteria, offering a natural alternative to agrochemicals. This approach not only helps reduce environmental pollution but also lowers toxin consumption and production costs. This study aimed to evaluate the effects of Cymbopogon and Pelargonium essential oils on the pathogenic bacteria P. carotovorum and P. stewartii. The essential oils were extracted and analyzed using gas chromatography-mass spectrometry (GC-MS) to identify their chemical constituents. Their antibacterial activity was assessed through the disk diffusion method, while the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Additionally, the combined effects of the two essential oils were studied using transmission electron microscopy (TEM). GC-MS analysis identified 75.64% of Cymbopogon’s essential compounds and 81.12% of Pelargonium’s. The largest inhibitory zone was observed with Cymbopogon essential oil against P. carotovorum (28 ± 2.54 mm), while the smallest was seen with Pelargonium essential oil against P. stewartii (9 ± 0.81 mm). The MIC and MBC values of the essential oils against the pathogens ranged from 2-3 mg ml–1. A synergistic antibacterial effect was also noted when the Cymbopogon and Pelargonium oils were combined. TEM analysis revealed that Cymbopogon essential oil caused significant structural damage to P. carotovorum bacterial cells, including complete cell destruction, damage to the cell wall, swelling of the nuclear area, and changes in cytoplasmic density.

Keywords

Antibacterial

Essential oils

MIC

MBC and GC‒MS