Antimicrobial activity of the bioactive components of essential oils from Pakistani spices against Salmonella and other multi-drug resistant bacteria

Abstract

BackgroundThe main objective of this study was the phytochemical characterization of four indigenous essential oils obtained from spices and their antibacterial activities against the multidrug resistant clinical and soil isolates prevalent in Pakistan, and ATCC reference strains.MethodsChemical composition of essential oils from four Pakistani spices cumin (Cuminum cyminum), cinnamon (Cinnamomum verum), cardamom (Amomum subulatum) and clove (Syzygium aromaticum) were analyzed on GC/MS. Their antibacterial activities were investigated by minimum inhibitory concentration (MIC) and Thin-Layer Chromatography-Bioautographic (TLC-Bioautographic) assays against pathogenic strains Salmonella typhi (D1 Vi-positive), Salmonella typhi (G7 Vi-negative), Salmonella paratyphi A, Escherichia coli (SS1), Staphylococcus aureus, Pseudomonas fluorescens and Bacillus licheniformis (ATCC 14580). The data were statistically analyzed by using Analysis of Variance (ANOVA) and Least Significant Difference (LSD) method to find out significant relationship of essential oils biological activities at p <0.05.ResultsAmong all the tested essential oils, oil from the bark of C. verum showed best antibacterial activities against all selected bacterial strains in the MIC assay, especially with 2.9 mg/ml concentration against S. typhi G7 Vi-negative and P. fluorescens strains. TLC-bioautography confirmed the presence of biologically active anti-microbial components in all tested essential oils. P. fluorescens was found susceptible to C. verum essential oil while E. coli SS1 and S. aureus were resistant to C. verum and A. subulatum essential oils, respectively, as determined in bioautography assay. The GC/MS analysis revealed that essential oils of C. cyminum, C. verum, A. subulatum, and S. aromaticum contain 17.2% cuminaldehyde, 4.3% t-cinnamaldehyde, 5.2% eucalyptol and 0.73% eugenol, respectively.ConclusionsMost of the essential oils included in this study possessed good antibacterial activities against selected multi drug resistant clinical and soil bacterial strains. Cinnamaldehyde was identified as the most active antimicrobial component present in the cinnamon essential oil which acted as a strong inhibitory agent in MIC assay against the tested bacteria. The results indicate that essential oils from Pakistani spices can be pursued against multidrug resistant bacteria.

Chemical Constituents and Antimicrobial Activities of Essential Oils Of syzygiumpolyanthum and Syzygiumaromaticum

“…The MIC of essential oil of buds of S. aromaticum against tested bacteria was 3260-8600 µg/mL. It relatively inactive against Listeria monocytogenes, with MIC of 12500-50000 µg/mL 17,34 .In our study, MICs of essential oil of S. aromaticum against E. coli, S. aureus, S. typhimurium and V. cholera were in agreement with those reports. The MIC of essential oil of S. aromaticum against B. subtilis was considerably lower than those previously reported data.…”

“…aromaticum had been known widely as a potent antimicrobial against various bacteria and fungi, with eugenol as the active ingredient. [15][16][17][18] In this study, we compared chemical constituents of essential oils of S. polyanthum and S. aromaticum and evaluated their minimal inhibitory concentration (MIC) against the common foodborne microorganisms in Indonesia.…”

Antimicrobial Activities of Unconventional Compounds against Some Bacteria Associated with Skin Infections in Humans, Sheep and Goats

“…The Gramnegative E. coli was comparatively resistant to Grampositive bacteria, this may be due to the structure differences in cell membrane and cell wall structure, Gram-negative has outer membrane as well which further block the penetration of antibiotics including the extracts of spices making them resistant. The garlic extract is effective against different serotype of E. coli and also S. aureus (Naveed et al, 2013). Fresh garlic concentration 0.5-5.0% was sufficient to inhibit the growth of E. coli O157: H7 (Tessema et al, 2006).…”

Phytochemical Characterization of the Essential Oils Obtained from Mediterranean Thymus spp. (Lamiacea) Harvested at Different Stages of Growth

“…diffuse across cell membrane to induce biological reactions [23]. The most represented chemical groups in the four species selected in the present study are oxygenated monoterpenes (phenolics compounds) with 76.96%~82.11%; the monoterpene hydrocarbons were present with approximately 26% in the four species.…”