Ghazal Tasneem Sultan Abu, Schelz Zsuzsanna, Vidács Lívia, Szemerédi Nikoletta, Veres Katalin, Spengler Gabriella, Hohmann Judit
Department of Pharmacognosy, University of Szeged, H-6720 Szeged, Hungary.
Department of Pharmacodynamics and Biopharmacy, University of Szeged, H-6720 Szeged, Hungary.
Plants (Basel). 2022 May 27;11(11):1432. doi: 10.3390/plants11111432.
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 L, and its monoterpenes for antimicrobial, bacterial multidrug resistance reversing, and biofilm formation inhibitory potency. The composition of EO and -hexane extract was characterized by GC-MS. In the essential oil terpinen-4-ol (24.92%), -sabinene hydrate (25.18%), γ-terpinene (6.48%), -sabinene hydrate (5.44%), -cymene (4.72%), sabinene (4.53%), α-terpineol (4.43%), and α-terpinene (3.00%) were found as the main constituents while -sabinene hydrate (1.43%), and terpinen-4-ol (0.19%) were detected in the -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 , and 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 ATCC 25922, and AG100 and ATCC 25923, and MRSA ATCC 43300 strains, EO exhibited substantial activity, especially in the ATCC 25922 strain. Among the EO constituents, only sabinene was an EP inhibitor in sensitive strain. In the case of 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 ATCC 25922 and MRSA ATCC 43300, while EO was ineffective on these strains. In contrast to this, biofilms formed by AG100 and 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.
L. 是一种广泛使用的药用植物；其蒸馏油和制剂在植物疗法和食品工业中被广泛应用。本研究的目的是评估L. 的提取物、精油（EO）及其单萜类化合物的抗菌、逆转细菌多药耐药性和抑制生物膜形成的效力。通过气相色谱 - 质谱联用（GC - MS）对EO和正己烷提取物的成分进行了表征。在精油中，发现萜品 - 4 - 醇（24.92%）、水合桧烯（25.18%）、γ - 萜品烯（6.48%）、水合桧烯（5.44%）、对异丙基甲苯（4.72%）、桧烯（4.53%）、α - 萜品醇（4.43%）和α - 萜品烯（3.00%）为主要成分，而在正己烷提取物中除了一系列烃类外，还检测到水合桧烯（1.43%）和萜品 - 4 - 醇（0.19%）。还评估了EO以及萜品 - 4 - 醇、α - 萜品烯和芳樟醇对敏感和耐药的 、 菌株的抗菌活性，其最低抑菌浓度（MIC）值分别为0.125 - 0.250%和30 - 61 μM。在通过溴化乙锭积累法对大肠埃希菌ATCC 25922、AG100和肺炎克雷伯菌ATCC 25923以及耐甲氧西林金黄色葡萄球菌ATCC 43300菌株进行的外排泵（EP）抑制试验中，EO表现出显著活性，尤其是在大肠埃希菌ATCC 25922菌株中。在EO成分中，只有桧烯是敏感 菌株中的EP抑制剂。对于 菌株，EO和水合桧烯在耐药表型上表现出中等效力。通过在亚最低抑菌浓度下的结晶紫染色测试了样品的抗生物膜作用。发现γ - 萜品烯、萜品 - 4 - 醇、桧烯、水合桧烯和芳樟醇是大肠埃希菌ATCC 25922和耐甲氧西林金黄色葡萄球菌ATCC 43300生物膜形成的有效抑制剂（抑制率36 - 86%），而EO对这些菌株无效。与此相反，EO显著抑制了AG100和肺炎克雷伯菌ATCC 25923形成的生物膜；然而，它不受任何单萜类化合物的影响。这一观察结果表明，精油成分之间的协同作用可能会改变抗生物膜效果。
