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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

From: Putative metabolic pathway for the bioproduction of bikaverin and intermediates thereof in the wild Fusarium oxysporum LCP531 strain

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

  1. Underlined data highlighted the best extraction solvent for each considered secondary metabolite
  2. ni not identified, nd not determined
  3. 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