ABSTRACT
Aloysia triphylla essential oil (EO) has antimicrobial activity on Staphylococcus aureus which is a pathogen responsible for severe infections and food contamination. The target of EO is mainly in the cytoplasmic membrane. In this work the mechanisms of action of the EO of A. triphylla on S. aureus were investigated. A. triphylla was collected from La Paz. The oil was analyzed by GC-MS. The antimicrobial effects were evaluated by MIC, MBC, killing time and TEM. MIC values were 23 μg/mL for 6.3 x 104 CFU/mL, 92 μg/mL for 5.71 x 105 CFU/mL and 180 μg/mL for 9 x 106 CFU/mL. The MBC was 5920 μg/mL for all cellular concentrations and it was necessary more time to kill bigger cell populations. Multilamellar and mesosome-like structures on the membrane were seen by TEM. A. triphylla oil is an antibacterial compound against S. aureus which main mechanism of action seems to be the cytoplasmic membrane disruption.
El aceite esencial (AE) de Aloysia triphylla posee actividad antimicrobiana contra Staphylococcus aureus, patógeno responsable de infecciones nosocomiales e alimenticias. El blanco de acción de los AE es la membrana citoplasmática. El mecanismo de acción del AE de A. triphylla sobre S. aureus fue investigado. El AE de A. triphylla (La Paz, Argentina) fue analizado por CG-EM. Se evaluó́ el efecto antimicrobiano por CIM, CBM, tiempo de muerte y MET. Los valores de CIM fueron 23 μg/mL para 6.3 x 104 UFC/mL, 92 μg/mL para 5.71 x 105 UFC/mL y 180 μg/mL para 9 x 106 UFC/mL. La CBM fue 5920 μg mL para todas las concentraciones celulares estudiadas. El tiempo de muerte fue determinado; necesitando mayor tiempo para matar una población celular elevada. Fueron observados por MET estructuras multilamerales y semejantes a mesosomas. El AE de A. triphylla es un potencial compuesto antibacteriano contra S. aureus donde su principal mecanismo de acción es por disrupción de la membrana citoplasmática.
Subject(s)
Anti-Bacterial Agents/pharmacology , Oils, Volatile/pharmacology , Plant Extracts/pharmacology , Staphylococcus aureus , Verbenaceae/chemistry , Gas Chromatography-Mass Spectrometry , Microbial Sensitivity Tests , Microscopy, Electron, Transmission , Oils, Volatile/chemistryABSTRACT
In the present investigation, anti-Candida activity of four essential oils i.e. Black cumin (Nigella sativa), Curry leaf (Murraya koienigii), Ajwain (Trachiyspirum ammi), and Betel leaf (Piper betel) were screened against four human pathogenic species of Candida viz. Candida albicans, Candida tropicalis, Candida glabrata, and Candida parapsilosis. The minimum inhibitory concentration (MIC) values of the oils ranged between 15.62 and 250 l/ml while studied through tube dilution method. The oils retained their anti-Candida activities even after heat treatment (at 45ºC, 60ºC, 100ºC for 1 hour) and also on autoclaving. Both Ajwain and Black Cumin leaf oils showed better anti-Candida activity against Candida albicans, resulting in an irreversible damage to the cells. The anti-Candida activity of these essential oils could be attributable to the membrane inhibition mechanism. The activity of the oils is reported to be microbicidal (Candida-cidal).