Pinus koraiensis Essential Oil Attenuates the Pathogenicity of Superbacteria by Suppressing Virulence Gene Expression

Abstract

In the quest to combat infections attributable to antibiotic-resistant superbacteria, an essential oil derived from the needles of Pinus koraiensis Sieb. et Zucc. (PKEO) has emerged as a promising solution. In this study, we demonstrate that PKEO can be used to inhibit the growth, glucose metabolite acidogenicity, and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA). Quantitative PCR analysis provided direct evidence that PKEO reduces the mRNA expression of the accessory gene regulator A (agrA) and staphylococcal accessory regulator A (sarA), thereby indicating its inhibitory effect on pathogenic regulatory genes. Chromatographic analyses of PKEO identified terpene hydrocarbons as prominent essential oil constituents. These compounds, notably α-pinene, limonene, and β-caryophyllene, have been established to have antimicrobial properties. Our findings indicate that an oil derived from P. koraiensis can effectively combat antibiotic-resistant strains by disrupting the pathogenicity regulatory system, thereby establishing PKEO as a promising candidate for the treatment of MRSA infections.

Antioxidant Activity of Essential Oils from Pinaceae Species

“…EOs from various parts of many other Pinaceae species have also been evaluated for their antimicrobial effects, for instance, P. banksiana [ 44 ], P. brutia [ 145 , 146 ], P. cembra [ 39 , 79 ], P. densiflora [ 76 , 94 , 147 , 148 , 149 , 150 ], P. eldarica [ 127 , 151 ], P. halepensis [ 83 , 95 , 136 , 152 , 153 , 154 ], P. heldreichii [ 92 ], Pinus kesiya Royle ex Gordon (syn. P. insularis ) [ 155 ], P. koraiensis [ 148 , 156 , 157 , 158 ], P. merkusii Jungh. & de Vriese [ 155 ], P. monticola [ 159 ], P. mugo [ 39 , 92 , 160 ], P. nigra [ 74 , 92 , 160 , 161 , 162 ], P. nigra subsp.…”

“…In other cases, though, it is difficult to establish whether a connection exists between the observed pharmacological effects and the antioxidant properties of an EO or its ingredients, or mechanisms independent of the antioxidant effects are proposed. For instance, based on molecular dockings (with its known limitations), it was suggested that germacrene D-4-ol (from P. nigra EOs) would act by inhibiting FtsZ, a tubulin homolog in bacteria [ 74 ], a leaf EO of P. koraiensis would act on S. aureus by inhibiting specific bacterial regulatory genes involved in pathogenicity [ 158 ], while a P. sylvestris EO would inhibit beta-lactamase, as suggested by molecular ligand docking [ 177 ].…”