Table 1.
Description and MICs of active compounds of Maslinic acid library against E. faecium NR-31909.
Table 2.
MIC values (μg/mL) of the Maslinic acid and control antibiotics against clinical isolates of enterococci.
Table 3.
MBC (μg/mL) of Maslinic acid against enterococci strains.
Fig 1.
Time kill assay of maslinic acid at 5 × and 10 × MIC and linezolid at 10 × MIC, against E. faecium NR-31909.
Samples treated with DMSO were used as negative control. The results are given as means ± SD (n = 3; data without error bars indicate that the SD is too small to be seen).
Fig 2.
Cytotoxicity assay showing the percent mean absorbance at 490 nm after incubating Caco-2 cells with maslinic acid at different concentrations for 24 hr.
Cell viability was measured by MTS assay. Results are expressed as means from three measurements ± standard deviations. All experiments were done in triplicate. Statistical analyses were determined by one-way ANOVA with post hoc testing (*p < 0.05). ns, non-significant.
Fig 3.
Hemolysis assay of maslinic acid on human RBCs.
The release of hemoglobin in the supernatant of human erythrocytes after treatment with increasing amounts of the two compounds was measured at 405 nm. Data collected after 1 h of incubation are presented. 0.1% of Triton X-100 served as positive control. All experiments were done in triplicate. Statistical analyses were determined by one-way ANOVA with post hoc testing. ns, non-significant.
Fig 4.
The effect of maslinic acid and linezolid on the biofilms of E. faecalis NR-31887.
The adherent biofilm was stained by crystal violet, then the dye was extracted with ethanol, measured at 595 nm absorbance and presented as percentage of biofilm reduction compared to untreated wells. All experiments were done in triplicate. Statistical analyses were determined by one-way ANOVA with post hoc testing (**p < 0.01). ns, non-significant.
Fig 5.
In vivo efficacy of maslinic acid in a Caenorhabditis elegans model of bacterial infection.
C. elegans were infected with VRE, E. faecium NR-31909. After infection, worms were treated with maslinic acid or linezolid at 10 × MIC. After 24 hours, worms were lysed, and bacteria were plated and CFU were counted after 24 hr. Results are expressed as means from three biological replicates ± standard deviation. Statistical analyses were determined by one-way ANOVA with post hoc testing (***p < 0.005), (****p < 0.0001).