Isolation and characterization of cyclo-(tryptophanyl-prolyl) and chloramphenicol from Streptomyces sp. SUK 25 with antimethicillin-resistant Staphylococcus aureus activity

Figures & data

Table 1 Isolation and purification details of secondary metabolite compounds, diameter of inhibition zone, MIC values (µg/mL), and MBC values (µg/mL) of active fractions against MRSA ATCC 43300

Fraction number	Weight (mg)	IZ (mm)	MIC (µg/mL)	MBC (µg/mL)
FI	30	14	16	128
FII	51	15	8	32
FIII	45	–	–	–
FIV	43	–	–	–
FV	59	–	–	–
FVI	32	–	–	–
FVII	29	22	8	64
FVII-F2	11	15	16	32
FVII-F3	13	16	8	64
FVIII	77	–	–	–
FIX	26	13	16	128
FX	24	14	16	128
FXI	51	–	–	–
FXII	65	–	–	–
FXIII	64	–	–	–
Vanco	–	18	2	4

Abbreviations: MIC, minimum inhibitory concentration; MBC, minimum bactericidal concentration; MRSA, methicillin-resistant Staphylococcus aureus; ATCC, American Type Culture Collection; –, no activity; IZ, inhibition zone; Vanco, vancomycin (30 µg/mL).

Figure 1 Neighbor-joining tree showing the relationship of strain SUK 25 based on a 16S rRNA gene sequences (1,450 nucleotides with closely related members of the genus Streptomyces omiyaensis NBRC 13449T and Kitasatospora setae KM-6054 as the outgroup).

Abbreviations: SUK 25, strain Universiti Kebangsaan 25; rRNA, ribosomal RNA.

Figure 2 TLC analysis of whole-cell hydrolysate of SUK 25.

Notes: All triplicate test strains of SUK 25 contain ll-DAP isomers (2, 3, and 4) similar in chromatographic behavior to that produced by the standard marker (1). The amino acid spots appeared purple or red and migrated up to DAP.
Abbreviations: TLC, thin-layer chromatography; SUK 25, strain Universiti Kebangsaan 25; DAP, diaminopimelic acid.

Table 2 1D-¹H NMR and ¹³C NMR spectrum data of FVII-F2 cyclo-(l-tryptophanyl-l-prolyl)

Number	δ H (J in Hz)	δ ^13C
1	–	–
2	3.76 Ha, 2.97 Hb	28.19 (CH2-2)
3	2.36–1.90	22.48 (CH2-3)
3a	–	–
4	2.36–1.90	26.76 (CH2-4)
5	4.08	59.18 (CH-5)
6	–	165.68 (Cq-6)
7	5.75 NH	–
7a	–	–
8	4.39	54.60 (CH-8)
9	–	169.48 (Cq-9)
10	3.64	45.33 (CH2-10)
11	–	111.61 (Cq-11)
12	7.61–7.14	123.39 (CH-12)
13	8.20 NH	–
14	–	136.81 (Cq-14)
15	–	126.85 (Cq-15)
16	7.61–7.14	122.81 (CH-16)
17	7.61–7.14	120.04 (CH-17)
18	7.61–7.14	118.55 (CH-18)
19	7.61–7.14	109.99 (CH-19)

Note: “–” indicates no hydrogen or carbon attached.

Abbreviations: 1D, one-dimensional; NMR, nuclear magnetic resonance; delta, δ, chemical shift scales in NMR; J, coupling constants in hertz.

Figure 3 The chemical structure elucidation of cyclo-(l-tryptophanyl-l-prolyl).

Table 3 1D-¹H NMR and ¹³C NMR spectrum data of FVII-F3 chloramphenicol

Position	δ H (J in Hz)	δ C	HMBC (H-C)
1	–	148.6	–
2, 6	8.3 (2H) m	126.9	H6 (C-1, 4)
3, 5	7.67 (2H) m	126	H3 (C-1, 2, 7)
4	–	150.2	–
7	5.18	69.9	H7 (C4, 5, 8, 9)
8	4.16	57.10	H8 (C-10)
9	3.62–3.8, 2H, dd, J=6.0 Hz; 12.0 Hz	60.80	–
10	–	165.2	–
11	6.3	66.0 (d, CH-Cl2)	H11 (C-10)

Note: “–” indicates no hydrogen or carbon attached.

Abbreviations: 1D, one-dimensional; NMR, nuclear magnetic resonance; delta, δ, chemical shift scales in NMR; J, coupling constants in hertz; HMBC, heteronuclear multiple-bond correlation.

Figure 4 The chemical structure elucidation of chloramphenicol using 2D-NMR HMBC and COSY correlations of FVII-F3 compound.

Note: ¹H–¹³C HMBC correlation → ¹H –¹H COSY correlation.
Abbreviations: 2D-NMR, two-dimensional nuclear magnetic resonance; HMBC, heteronuclear multiple-bond correlation; COSY, correlations spectroscopy.