In vitro antimicrobial activity of extracts and essential oils of Cinnamomum, Salvia, and Mentha spp. against foodborne pathogens: a meta-analysis study
Essential oils (EOs) are a class of natural products that exhibit potent antimicrobial
properties against a broad spectrum of bacteria. Inhibition diameters
(IDs) and minimum inhibitory concentrations (MICs) are the typical measures of
antimicrobial activity for extracts and EOs obtained from Cinnamomum, Salvia,
and Mentha species. This study used a meta-analytical regression analysis to
investigate the correlation between ID and MIC measurements and the variability
in antimicrobial susceptibility tests. By utilizing pooled ID models, this
study revealed significant differences in foodborne pathogens’ susceptibility to
extracts, which were dependent on both the plant species and the methodology
employed (p < .05). Cassia showed the highest efficacy against Salmonella spp.,
exhibiting a pooled ID of 26.24 mm, while cinnamon demonstrated the highest
efficacy against Bacillus cereus, with a pooled ID of 23.35 mm. Mint extract
showed the greatest efficacy against Escherichia coli and Staphylococcus aureus.
Interestingly, cinnamon extract demonstrated the lowest effect against Shiga
toxin-producing E. coli, with a pooled ID of only 8.07 mm, whereas its EOs were
the most effective against this bacterial strain. The study found that plant species
influenced the MIC, while the methodology did not affect MIC measurements
(p > .05). An inverse correlation between ID and MIC measurements was identified
(p < .0001). These findings suggest that extracts and EOs obtained from
Cinnamomum, Salvia, and Mentha spp. have the potential to inhibit bacterial
growth. The study highlights the importance of considering various factors that may influence ID and MIC measurements when assessing the effectiveness of
antimicrobial agents.
Genetic analysis of the honey bee spermathecal content can be particularly useful to provide
an estimate of the genetic diversity and purity of the surrounding populations. Here we
compared the concentration and quality of DNA extracted from queen spermatheca using
four commercial kits to determine the best method to obtain DNA suitable for single nucleotide
polymorphism genotyping by next-generation sequencing. The four kits were tested
with different adjustments in the lysis incubation time, use of RNA-carrier, elution conditions
and number of re-elutions. Only the use of QIAamp DNA Microkit with 3 h of lysis incubation,
the addition of RNA-carrier and multiple re-elutions produced a DNA concentration
over the required threshold.
