Antimicrobial and antibiofilm activity of the essential oil from dried leaves of Eucalyptus staigeriana

Abstract

In recent years, compounds with biological properties produced by plants have received attention as an alternative to control microorganisms. Essential oils extracted from green leaves of Eucalyptus sp. have been demonstrated to have antimicrobial activities, but so far there are no reports of antimicrobial activity of essential oils extracted from dried leaves of Eucalyptus staigeriana. So, the objectives of this study were to determine the chemical composition of the essential oils obtained from dried leaves of E. staigeriana (EOdlES) and to evaluate in vitro antimicrobial and antibiofilm activities of EOdlES against gram-positive and gram-negative, resistance and multiresistant Enterococcus faecalis isolated from food and clinical samples. The characterization of EOdlES was performed by gas chromatography-mass spectrometry (GC/MS). For this study, 26 bacterial strains were used, which included 11 reference strains and 15 antibiotic resistant and multiresistant E. faecalis strains. Antimicrobial activities of EOdlES against gram-positive and gram-negative were determined using the disc diffusion method. The minimum inhibitory concentration (MIC) value was evaluated by a microbroth dilution technique. The antibiofilm effects were assessed by microtiter plate method. As a result, 21 compounds were identified, being oxygenated monoterpenes (69.58%) the major chemical family. EOdlES showed only antimicrobial activity against gram-positive strains. E. faecalis resistant and multiresistant strains show the lowest MIC (3.12 to 6.25%), when compared with reference E. faecalis strain. EOdlES has the ability to inhibit the biofilm formation, but little or none ability to inhibit the preformed biofilm. This study demonstrates that EOdlES is a promising alternative to control important foodborne and clinic gram-positive resistant bacteria.

Repellent, Insecticidal and Antimicrobial Activities of Leaf Essential Oils from Three Eucalyptus Species

“…Essential oils are complex mixtures of volatile organic substances, consisting of oxygenated compounds and hydrocarbons, such as sesquiterpenes and monoterpenes, were widely applied in food, perfumes, toiletries, chemical additives, medicine and pharmaceutical science . Many plant essential oils and their major constituents exhibit a wide range of biological properties, such as insecticidal, antibacterial, antifungal, spasmolytic, and so on . Due to the great value, the development of essential oils from plants and evaluation on their activities is still highly desirable.…”

Materialization of novel composite bio‐based active edible film functionalized with essential oils on antimicrobial and antioxidative aspect of chicken nuggets during extended storage

“…In general, relatively higher inhibition for Gram‐positive bacteria was observed as compared to the Gram‐negative test bacteria. Arya, Mendiratta, Agarwal, Bharti, and Umarao (2019); Correa, Schwambach, Mann, Frazzon, and Frazzon (2019) also reported the higher sensitivity of Eucalyptus staigeriana and Oregano EO over Gram‐positive pathogenic bacteria than Gram‐negative bacteria. This phenomenon could be attributed to the intrinsic tolerance of bacteria as well as the nature of phytochemical compounds present in the EO.…”

Review: Essential Oils A Viable Pest Control Alternative

“…Antimicrobial and antifungal activities displayed by essential oils have been extensively documented in the literature [56][57][58]. Nevertheless, there are some limitations associated with their sensitivity to light and temperature, as well as their volatility and poor water solubility [59].…”