Table 3.
Fractional inhibitory concentration index (FICI) of essential oils plus itraconazole
| Antifungal agents | C. neoformans ADS 37 (azole susceptible strain) | C. neoformans ADS 006 (azole not-susceptible strain) | |
|---|---|---|---|
| ITC | MIC (μg/ml) alone | 0.5 | 2 |
| Origanum vulgare | MIC (mg/ml) alone | 0.3 | 0.3 |
| FIC of oregano oil | 0.125 | 0.5 | |
| FIC of ITC | 0.25 | 0.125 | |
| FICI | 0.375 | 0.625 | |
| Interpretation | SYN | ADD | |
| Pinus sylvestris | MIC (mg/ml) alone | 0.14 | 0.54 |
| FIC of pine oil | 0.25 | 1 | |
| FIC of ITC | 0.125 | 0.125 | |
| FICI | 0.375 | 1.125 | |
| Interpretation | SYN | IND | |
| Thymus vulgaris | MIC (mg/ml) alone | 0.56 | 1.12 |
| FIC of thyme red oil | 0.125 | 0.25 | |
| FIC of ITC | 0.25 | 0.125 | |
| FICI | 0.375 | 0.375 | |
| Interpretation | SYN | SYN | |
| (+)-α-pinene | MIC (mg/ml) alone | 0.54 | 1.07 |
| FIC of α-pinene | 0.125 | 0.5 | |
| FIC of ITC | 0.5 | 0.125 | |
| FICI | 0.625 | 0.625 | |
| Interpretation | ADD | ADD | |
| Carvacrol | MIC (mg/ml) alone | 0.6 | 0.6 |
| FIC of carvacrol | 0.125 | 0.25 | |
| FIC of ITC | 0.125 | 0.125 | |
| FICI | 0.25 | 0.375 | |
| Interpretation | SYN | SYN | |
| Thymol | MIC (mg/ml) alone | 0.04 | 0.08 |
| FIC of thymol | 1 | 1 | |
| FIC of ITC | 1 | 0.125 | |
| FICI | 2 | 1.125 | |
| Interpretation | IND | IND | |
FIC of ITC = MIC of ITC in combination with EO/MIC of ITC alone. FIC of EO = MIC of EO in combination with ITC/MIC of EO alone
FICI (FIC Index) = FIC of ITC + FIC of EO. IND: indifferent; ADD: additive; SYN: synergy