Table 6.
MIC values of isolated compounds from S. hillii methanol extract.
| Bacterial Strain | Antibiotic Standard | Compounds (µg/mL) | ||
|---|---|---|---|---|
| Name | MIC (µg/mL) | Quercetin | Shikimic Acid | |
| Gram-positive bacteria | ||||
| Bacillus cereus (ATCC 14579) | Erythromycin | 5.0 | >200.0 | >200.0 |
| MRSA (ATCC 33591) | SXT | 5.0 * | >200.0 | >200.0 |
| Enterococcus faecalis (QUT 1105) | Teicoplanin | 30.0 * | 0.78 | 200.0 |
| Gram-negative bacteria | ||||
| Proteus vulgaris (ATCC 6380) | SXT | 5.0 | 200.0 | >200.0 |
| Acinetobacter baumannii (ATCC 19606) | Gentamicin | 10.0 * | >200.0 | >200.0 |
| Enterobacter cloacae (ATCC 13047) | Gentamicin | 20.0 * | 200.0 | 200.0 |
| Klebsiella pneumoniae (ATCC 27736) | Gentamicin | 2.0 * | >200.0 | >200.0 |
| Pseudomonas aeruginosa (ATCC 27853) | Gentamicin | 10.0 * | 200.0 | 200.0 |
Quercetin-3-O-β-D-glucuronide inhibited E. faecalis at 0.78 µg/mL, P. vulgaris at 200 µg/mL, P. aeruginosa at 200 µg/mL, and E. cloacae at 200 µg/mL. Shikimic acid inhibited the growth of E. faecalis, E. cloacae, and P. aeruginosa at 200 µg/mL. MIC values were determined by the lack of INT reduction to INT formazan measured at 550 nm and expressed as the mean of triplicates. Test performed in three replicates (n = 3). SXT: trimethoprim + sulfamethoxazole. MSSA: methicillin-sensitive Staphylococcus aureus. MRSA: methicillin-resistant Staphylococcus aureus. *: MIC values obtained from EUCAST (The European Committee on Anti-microbial Susceptibility Testing).