Chemical Profile of Essential oil of Ocimum gratissimum L. and Evaluation of Antibacterial and Drug Resistance-modifying Activity by Gaseous Contact Method

Abstract

Introduction: Plant products with antimicrobial potential and ability to modulate the action of drugs have become the target of several studies. Many studies of the species Ocimum gratissimum Lamiaceae have reportedbiological activities in the essential oil and extracts of various parts of the plant. Objective: Evaluate the antibacterial and resistance-modifying activity of the essential oil of O. gratissimum (OEOg) and its major compound, Eugenol. Materials and Methods: OEOg was extracted by hydrodistillation and Eugenol was obtained commercially. Multiresistant strains of Escherichia coli and Staphylococos aureus were used to test for drug activity. Antibacterial and resistance-modifying activity of OEOg and Eugenol was evaluated by gaseous contact. Results: Chemical analysis of OEOg demonstrated the presence of Eugenol and other compounds such as 1, 8-cineole and β-selinene as well. In the evaluation of the antibacterial activity, both OEOg and Eugenol were unable to form a bacterial growth inhibition zone at any of the concentrations tested. However, the modulation tests with amikacin and erythromycin identified synergism with OEOg and eugenol against E. coli and S. aureus. Gentamicin combined with OEOg showed antagonism against S. aureus but synergism against E.coli. When gentamicin was combined with Eugenol, there was also synergism against S. aureus, whereas no effect was seen against E. coli. Conclusion: Given the results obtained in this study, it is concluded that OEOg and Eugenol may eventually represent a new therapeutic tool against antibiotic-resistant bacteria.

Evaluation of antibiotic efficacy of Ocimum gratissimum L. essential oil against Staphylococcus aureus and Pseudomonas aeruginosa

“…Our results showed a higher eugenol content (74.2%) in EOGT when compared with the studies published by Ribeiro et al (2016) and Chimnoi et al (2018). This compound is essential for EOGT chemotype and is a basis for its antibacterial activity (Silva et al, 2015b;Melo et al, 2019;Rodrigues et al, 2020). Like eugenol, other compounds, such as terpineol-4, γ-muurolene, (Z, E)-αfarnesene, α-trans-bergamotene, 1,8-cineole, β-selinene, γ-terpinene, p-cymene, thymol, and myrcene, have also been identified in the essential oil of O. gratissimum (Matasyoh et al, 2007;Chimnoi et al, 2018;Rodrigues Belo et al 59 et al, 2020;Yayi et al, 1999).…”

In vitro Acaricidal Activity of Ocimum gratissimum Essential Oil on Rhipicephalus sanguineus, Amblyomma sculptum and Rhipicephalus microplus Larvae

“…Ocimum gratissimum presents three important chemotypes (CT): CT eugenol, CT thymol and CT geraniol (Lima et al, 2018;Hue et al, 2015;Silva et al, 2015). 25, In our work, we identified eugenol as the major compound (74.5 %), followed by eucalyptol (1,8-cineol…”

“…17 O. gratissimum occurs spontaneously throughout Brazil, 18 and three chemotypes are known: thymol, geraniol and eugenol (the most common), which has an essential oil rich in two compound (eugenol and eucalyptol. 19 To ensure the efficacy and safety of using EOs to control ticks, it is first necessary to determine effective concentrations. In vitro activity evaluation and LC 50 establishment are important tools at this stage.…”