Table 2.
Determination on agar plates of the minimum inhibitory concentration (MIC) values of the ten methanol bark extracts against 22 microbial species. Tested concentrations ranged from 0.3 mg/mL to 10 mg/mL.
| Micro-Organism | MIC (mg/mL) | Positive Controls | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| E2-1 | E2-2 | E2-3 | E2-4 | E2-5 | E2-6 | E2-7 | E2-8 | E2-9 | E2-10 | G | V | A | |||
| Gram positive bacteria | Bacillus subtilis | 5 | ≤0.3 | ≤0.3 | ≤0.3 | 5 | 1.2 | 2.5 | 1.2 | 1.2 | 2.5 | S | S | NT | |
| Enterococcus faecalis ATCC 1034 | 10 | ≤0.3 | ≤0.3 | ≤0.3 | NA | 5 | 5 | 1.2 | 2.5 | 5 | R | R | NT | ||
| Staphylococcus aureus NCTC 8325 | 0.6 | ≤0.3 | ≤0.3 | ≤0.3 | NA | 2.5 | 2.5 | ≤0.3 | 1.2 | 5 | S | S | NT | ||
| Staphylococcus aureus CIP 53.154 | ≤0.3 | ≤0.3 | ≤0.3 | ≤0.3 | NA | 1.2 | 2.5 | 1.2 | 2.5 | 2.5 | S | S | NT | ||
| Staphylococcus epidermidis | 0.6 | ≤0.3 | ≤0.3 | ≤0.3 | 10 | 1.2 | 2.5 | ≤0.3 | ≤0.3 | 1.2 | S | S | NT | ||
| Listeria innocua | 5 | ≤0.3 | ≤0.3 | ≤0.3 | 5 | 2.5 | 5 | 1.2 | 1.2 | 2.5 | S | S | NT | ||
| Streptococcus pyogenes | 5 | ≤0.3 | ≤0.3 | ≤0.3 | ≤0.3 | ≤0.3 | 2.5 | ≤0.3 | ≤0.3 | ≤0.3 | S | S | NT | ||
| Micrococcus luteus | 1.2 | ≤0.3 | ≤0.3 | ≤0.3 | 5 | 2.5 | 2.5 | ≤0.3 | ≤0.3 | 2.5 | S | S | NT | ||
| Gram negative bacteria | Escherichia coli CIP 54.127 | NA | 2.5 | 0.6 | 10 | NA | NA | NA | NA | NA | NA | S | R | NT | |
| Enterobacter cloacae | NA | 2.5 | 0.6 | 10 | NA | NA | NA | NA | NA | NA | S | R | NT | ||
| Salmonella enterica | NA | 1.2 | 0.6 | 10 | NA | NA | NA | NA | NA | NA | S | R | NT | ||
| Serratia marcescens | NA | 1.2 | ≤0.3 | NA | NA | NA | NA | NA | NA | NA | S | R | NT | ||
| Proteus vulgaris | NA | ≤0.3 | ≤0.3 | 2.5 | NA | NA | NA | NA | NA | NA | S | R | NT | ||
| Klebsiella pneumoniae | NA | 2.5 | 0.6 | NA | NA | NA | NA | NA | NA | NA | R | R | NT | ||
| Providencia stuartii | NA | ≤0.3 | ≤0.3 | 2.5 | NA | NA | NA | NA | NA | NA | S | R | NT | ||
| Pseudomonas aeruginosa ATCC 9027 | NA | ≤0.3 | ≤0.3 | 10 | NA | NA | NA | NA | NA | NA | S | R | NT | ||
| Shigella sonnei | 0.6 | ≤0.3 | ≤0.3 | ≤0.3 | 10 | 1.2 | 2.5 | ≤0.3 | 0.6 | 1.2 | S | I | NT | ||
| Yeast | Candida glabrata | NA | ≤0.3 | ≤0.3 | ≤0.3 | NA | NA | NA | 10 | NA | NA | R | R | S | |
| Candida tropicalis | NA | ≤0.3 | 0.6 | ≤0.3 | NA | NA | NA | ≤0.3 | NA | NA | R | R | S | ||
| Candida kefyr | NA | ≤0.3 | ≤0.3 | ≤0.3 | NA | NA | NA | NA | NA | NA | R | R | S | ||
| Candida albicans | NA | ≤0.3 | 0.6 | ≤0.3 | NA | NA | NA | ≤0.3 | NA | NA | R | R | S | ||
| Cryptococcus neoformans | 2.5 | ≤0.3 | ≤0.3 | ≤0.3 | 2.5 | NA | NA | NA | NA | NA | R | R | S | ||
NT: Non tested; NA: No activity; S: Sensitive; I: Intermediate; R: Resistant. MIC (µg/mL) of positive controls: Gentamicin (G), S: ≤4, R: >8; Vancomycin (V), S: ≤4, R: >16; Amphotericin B (A), S: ≤1, R: >4. Green boxes: MIC <0.3 mg/mL; Yellow boxes: 0.3 mg/mL< MIC <10 mg/mL; Red boxes: 10 mg/mL< MIC.