Antimicrobial, Multidrug Resistance Reversal and Biofilm Formation Inhibitory Effect of Origanum majorana Extracts, Essential Oil and Monoterpenes

Abstract

Origanum majorana L. is a widely used medicinal plant; its distilled oil and preparations are extensively utilised in the phytotherapy and food industries. The objective of this study is to evaluate the extracts and the essential oil (EO) of Origanum majorana L, and its monoterpenes for antimicrobial, bacterial multidrug resistance reversing, and biofilm formation inhibitory potency. The composition of EO and n-hexane extract was characterized by GC-MS. In the essential oil terpinen-4-ol (24.92%), trans-sabinene hydrate (25.18%), γ-terpinene (6.48%), cis-sabinene hydrate (5.44%), p-cymene (4.72%), sabinene (4.53%), α-terpineol (4.43%), and α-terpinene (3.00%) were found as the main constituents while trans-sabinene hydrate (1.43%), and terpinen-4-ol (0,19%) were detected in the n-hexane extract besides a series of hydrocarbons. The antibacterial activity of EO and terpinen-4-ol, α-terpinene, and linalool was also assessed against sensitive and drug-resistant S. aureus, and E. coli strains with MIC values of 0.125–0.250% and 30–61 µM, respectively. In the efflux pump (EP) inhibitory assay, made by the ethidium bromide accumulation method in E. coli ATCC 25922, and AG100 and S. aureus ATCC 25923, and MRSA ATCC 43300 strains, EO exhibited substantial activity, especially in the E. coli ATCC 25922 strain. Among the EO constituents, only sabinene was an EP inhibitor in sensitive Escherichia strain. In the case of S. aureus strains, EO and sabinene hydrate exhibited moderate potency on the drug-resistant phenotype. The antibiofilm effects of the samples were tested by crystal violet staining at sub-MIC concentration. γ-Terpinene, terpinen-4-ol, sabinene, sabinene hydrate and linalool were found to be effective inhibitors of biofilm formation (inhibition 36–86%) on E. coli ATCC 25922 and S. aureus MRSA ATCC 43300, while EO was ineffective on these strains. In contrast to this, biofilms formed by E. coli AG100 and S. aureus ATCC 25923 were significantly inhibited by the EO; however, it was not affected by any of the monoterpenes. This observation suggests that the antibiofilm effect might be altered by the synergism between the components of the essential oil.

Furanonaphthoquinones, Diterpenes, and Flavonoids from Sweet Marjoram and Investigation of Antimicrobial, Bacterial Efflux, and Biofilm Formation Inhibitory Activities

“…majorana, the MeOH extract was prepared, which was subjected to solvent–solvent partition, yielding n -hexane and chloroform extracts. The antimicrobial effect of the MeOH and n -hexane extracts, together with the EO obtained via hydrodistillation were previously reported . The present paper deals with the antimicrobial activity of the chloroform extract and its constituents.…”

“…Contrary to majoranaquinone (1), the formation of S. aureus MRSA ATCC 43300 biofilm was inhibited by terpinene-4-ol, sabinene, sabinene hydrate, and linalool (inhibition, 28.87−86.26%), but on the sensitive S. aureus ATCC 25923, they were ineffective. 12 Several research groups have investigated the role of EPs in bacterial biofilm formation. EPs play different roles in biofilm formation; therefore, inhibition of their function could also inhibit biofilm formation.…”

“…11 In our previous study, the antibacterial activities of EO of O. majorana and its constituents were investigated in detail. 12 The present study was designed to examine the antimicrobial activity of non-volatile compounds because in the literature only a few references can be found regarding the antibacterial and antifungal effects of the compounds of O. majorana outside EO and its constituents. This study aimed to isolate the compounds of the chloroform extract, examine the effect of the extracts and compounds against bacteria and fungi and for their ability to reverse bacterial resistance and inhibit biofilm formation.…”

“…In our previous study, the antibacterial activities of EO of O. majorana and its constituents were investigated in detail . The present study was designed to examine the antimicrobial activity of non-volatile compounds because in the literature only a few references can be found regarding the antibacterial and antifungal effects of the compounds of O.…”

Endophytic Streptomyces rochei BpR-2 GER (ON142045) from Bryophyllum pinnatum (Lam.) Oken with Antimicrobial and Antibiofilm Potential

“…Continuous amplification of antimicrobial resistance (AMR) in pathogens has escalated a health threat worldwide. As a result, difficulty in the treatment of AMR -associated infections has become an alarming problem, accelerating the rate of morbidity and mortality (1) . Multidrug-resistant pathogens (MDR) possess extensive genetic and phenotypic mechanisms to withstand antibiotic treatment.…”