Table 2.
Intracellular (IC) secondary metabolites including naphthoquinone pigments (expressed in volumetric production in meqv L−1 of culture broth) extracted by pressured liquid extraction from the mycelia of the Fusarium oxysporum LCP531 strain grown either in DMD or PDB broth, according to the polarity index of the extraction solvent
| Compound no | Colour | λmax in visible (in nm) | m/z [M+H]+ (in g mol−1) | Extraction solvent (amount of the metabolites in each extract) | Total amount extracted (in meqv L−1 of culture broth) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| H2O | 50% MeOH | 50% EtOH | MeOH | MeOH/EtOH | EtOH | |||||
| Solvent polarity index: | 10.0 | 7.5 | 7.0 | 5.0 | 4.5 | 4.0 | ||||
| Mycelium grown in DMD | ||||||||||
| Bikaverin 1 | Red | 507 | 383 | 0.5 ± 0.1 | 3.7 ± 0.2 | 4.8 ± 0.4 | 7.1 ± 0.4 | 10.3 ± 0.8a | 4.8 ± 0.3 | 31.2 ± 2.2 |
| Norbikaverin 2 | Red | 509 | 369 | < 0.1 | 11.2 ± 0.8 | 20.4 ± 1.2b | 13.0 ± 0.9 | 12.1 ± 0.6 | 4.8 ± 0.2 | 61.5 ± 3.7 |
| Oxo-pre-bikaverin 3 | Yellow | 382, 441 | 339 | < 0.1 | 2.7 ± 0.2c | 2.1 ± 0.2 | 1.6 ± 0.2 | 1.1 ± 0.1 | 0.2 ± 0.1 | 7.7 ± 0.8 |
| Me-oxo-pre-bikaverin 4 | Yellow | 376, 440 | 353 | < 0.1 | 3.8 ± 0.3d | 3.6 ± 0.2 | 2.7 ± 0.3 | 1.7 ± 0.2 | 0.9 ± 0.2 | 12.6 ± 1.2 |
| Dinor-bikaverin 5 | Yellow | 457 | 357 | < 0.1 | 0.7 ± 0.2 | < 0.1 | < 0.1 | < 0.1 | < 0.1 | 0.7 ± 0.2 |
| Pre-bikaverin 6 | Yellow | 438 | 323 | < 0.1 | < 0.1 | 0.2 ± 0.1 | < 0.1 | < 0.1 | < 0.1 | 0.2 ± 0.1 |
| Pigment ni 7a | Yellow | 376, 437 | nd | nd | nd | nd | nd | nd | nd | nd |
| Pigment ni 7b | Purple | 496, 523 | nd | < 0.1 | 0.4 ± 0.1 | 0.5 ± 0.1 | < 0.1 | < 0.1 | < 0.1 | 1.0 ± 0.2 |
| Pigment ni 7c | Purple | 491, 530 | nd | < 0.1 | < 0.1 | < 0.1 | 0.7 ± 0.2 | 0.5 ± 0.1 | 0.3 ± 0.1 | 1.5 ± 0.4 |
| Pigment ni 8 | Yellow | 430 | nd | < 0.1 | 0.4 ± 0.1 | 0.7 ± 0.2 | 0.8 ± 0.1 | 0.7 ± 0.1 | 0.7 ± 0.2 | 3.3 ± 0.7 |
| Pigment ni 9 | Purple | 516, 549 | nd | < 0.1 | 1.9 ± 0.2 | 1.3 ± 0.3 | 0.2 ± 0.1 | < 0.1 | < 0.1 | 3.4 ± 0.5 |
| Total pigments extracted (in meqv L−1 culture broth) | 0.5 ± 0.3 | 24.8e ± 2.1 | 33.6f ± 2.7 | 26.2g ± 2.2 | 26.4h ± 1.9 | 11.6 ± 1.1 | 123.1 ± 10.3 | |||
| > Other metabolites extracted | ||||||||||
| Beauvericin | – | 784 | nd | nd | nd | nd | nd | nd | nd | |
| Ergosterol derivate | – | 393 | < 0.1 | < 0.1 | 0.9 ± 0.1 | 12.8 ± 1.2 | 7.3 ± 0.4 | 0.5 ± 0.1 | 21.6 ± 1.8 | |
| Others (ni) | – | nd | 5.8 ± 0.4 | 12.8 ± 0.8 | 0.3 ± 0.1 | 0.5 ± 0.1 | 0.6 ± 0.2 | 1.3 ± 0.3 | 21.3 ± 1.9 | |
| Mycelium grown in PDB | ||||||||||
| Bikaverin 1 | Red | 507 | 383 | 1.0 ± 0.3 | 1.2 ± 0.2 | 2.3 ± 0.2 | 2.8 ± 0.5 | 7.8 ± 0.7a | 2.3 ± 0.3 | 17.6 ± 2.1 |
| Norbikaverin 2 | Red | 509 | 369 | 0.5 ± 0.1 | 2.3 ± 0.3 | 5.6 ± 0.4b | 3.4 ± 0.3 | 2.7 ± 0.2 | 0.6 ± 0.1 | 15.1 ± 1.4 |
| Oxo-pre-bikaverin 3 | Yellow | 382, 441 | 339 | < 0.1 | 7.1 ± 0.4c | 3.6 ± 0.3 | 1.7 ± 0.4 | 0.6 ± 0.2 | < 0.1 | 13.0 ± 1.3 |
| Me-oxo-pre-bikaverin 4 | Yellow | 376, 440 | 353 | < 0.1 | 8.3 ± 0.4d | 3.7 ± 0.2 | 2.2 ± 0.2 | 1.0 ± 0.3 | < 0.1 | 15.3 ± 1.1 |
| Dinor-bikaverin 5 | Yellow | 457 | 357 | < 0.1 | 0.6 ± 0.1 | 0.3 ± 0.1 | 0.1 ± 0.1 | < 0.1 | < 0.1 | 1.1 ± 0.3 |
| Pre-bikaverin 6 | Yellow | 438 | 323 | < 0.1 | < 0.1 | 0.2 ± 0.2 | < 0.1 | < 0.1 | < 0.1 | 0.3 ± 0.2 |
| Pigment ni 7a | Yellow | 376, 437 | nd | < 0.1 | 0.3 ± 0.1 | 0.2 ± 0.1 | 0.5 ± 0.2 | 0.5 ± 0.2 | < 0.1 | 1.5 ± 0.6 |
| Pigment ni 7b | Purple | 496, 523 | nd | nd | nd | nd | nd | nd | nd | nd |
| Pigment ni 7c | Purple | 491, 530 | nd | nd | nd | nd | nd | nd | nd | nd |
| Pigment ni 8 | Yellow | 430 | nd | < 0.1 | 0.2 ± 0.1 | 0.2 ± 0.1 | 0.3 ± 0.1 | 0.4 ± 0.1 | < 0.1 | 1.1 ± 0.4 |
| Pigment ni 9 | Purple | 516, 549 | nd | nd | nd | nd | nd | nd | nd | nd |
| Total pigments extracted (in meqv L−1 culture broth) | 1.5 ± 0.3 | 20.1i ± 1.6 | 16.0j ± 1.6 | 11.2k ± 1.8 | 13.2l ± 1.7 | 3.0 ± 0.4 | 65.0 ± 7.4 | |||
| > Other metabolites extracted | ||||||||||
| Beauvericin | – | 784 | nd | nd | nd | nd | nd | nd | nd | |
| Ergosterol derivate | – | 393 | < 0.1 | < 0.1 | 0.4 ± 0.2 | 5.0 ± 0.4 | 4.1 ± 0.3 | 0.7 ± 0.2 | 10.3 ± 1.1 | |
| Others (ni) | – | nd | 48.2 ± 2.9 | 5.6 ± 0.3 | 2.1 ± 0.3 | 0.3 ± 0.2 | 0.4 ± 0.2 | 0.9 ± 0.3 | 57.5 ± 4.2 | |
Underlined data highlighted the best extraction solvent for each considered secondary metabolite
ni not identified, nd not determined
aBikaverin is preferentially extracted by solvent with polarity index (p.i.) of 4.5; b Norbikaverin by solvent p.i. of 7.0; c,d Oxo-pre-bikaverin and Me-oxo-pre-bikaverin by solvent p.i. of 7.5; e corresponding to the extract IC2 shown in Fig. 1e and HPLC-DAD chromatogram shown in Fig. 2a; f extract IC3 in Fig. 1e and chromatogram in Fig. 2b; g extract IC4 in Fig. 1e and chromatogram in Fig. 2c; h extract IC5 in Fig. 1e and chromatogram in Fig. 2d; i extract IC8 shown in Fig. 1e and chromatogram in Fig. 3a; j extract IC9 in Fig. 1e and chromatogram in Fig. 3b; k extract IC10 in Fig. 1e and chromatogram in Fig. 3c; l extract IC11 shown in Fig. 1e and chromatogram in Fig. 3d