Diazaquinomycin

1. Discovery, producing organism and structures1,2)
Diazaquinomycins were isolated from Streptomyces fungal strain OM-704 while screening for
antifolate substances in microorganisms. Diazaquinomycin A inhibited the growth of Gram-positive bacteria. 11,18-Diacetoxydiazaquinomycin A exhibited antitumor activity against Meth-A
fibrosarcoma. The total synthesis of diazaquinomycin A has been reported by two groups (SeeAppendix-I). The first total synthesis was achieved by Kelly et al.3)

H3C

CH3

H3C

CH3O
H3C
OOH
CH3 H3CNHNOHODiazaquinomycin AOCH3NHNO
HOH
Diazaquinomycin B

Streptomyces sp. OM-704

2. Physical data (Diazaquinomycin A)
Red crystals. C20H22N2O4; mol wt 354.41. Slightly sol. in DMSO, MeOH, acetone, CHCl3. Insol.
in H2O, hexane.

=

3. Screening method4)
Most general microorganisms cannot incorporate folate-related compounds, but some special microorganisms such as Streptococcus sp. and Lactobacillus sp. require folate-related compounds
and thus can incorporate them. AnDihydropteroate
Pteroate
tifolates are used clinically as anticancer and antibacterial drugs. ToFolate
Dihydrofolate (DHF)
screen the antifolate compounds,
we selected a culture broth of soil
DHF reductase
isolates showing inhibitory activity
Leucovorin
Tetrahydrofolate (THF)
against a Streptococcus sp. grown(5-CHO-THF)
in a medium containing a limited
amount of pteroate, enough ami- 5,10-Methenyl-THF
5,10-Methylene-THF
no acids, bases, and nucleosides,
Thymidylate(except thymine and thymidinesynthase(TdR)), but lacking inhibitory ac▲tivity against organisms grown indUMPdTMPTdR
the same medium supplemented
with a sufficient amount of TdR.
DNA
Diazaquinomycin

5-FdUMP

5-FU4. Biological activity1,5,6)
1) Antimicrobial activities
Diazaquinomycin A inhibited the growth of Gram-positive bacteria (MIC: 3.13–50 µg/ml) withthe exception of Bacillus spp.
Test organism

MIC (µg/ml)

Staphylococcus aureus FDA 209P
6.25
Staphylococcus aureus ATCC 6538P
6.25
Staphylococcus aureus KB 199
6.25(erythromycin resistant)		
Staphylococcus aureus FS 1277
50(penicillin resistant)		
Streptococcus faecium IFO 3181
6.25
Streptococcus pyogenes C 203
100
Micrococcus luteus ATCC 9341
3.13

Test organism

MIC (µg/ml)

Bacillus subtilis ATCC 6633
Bacillus cereus IFO 3001
Mycobacterium smegmatis ATCC 607
Escherichia coli NIHJ JC-2
Klebsiella pneumoniae ATCC 10031
Proteus vulgaris IFO 3167
Serratia marcescens ATCC 8100
Pseudomonas aeruginosa IFO 3080

>100>100>100>100>100>100>100>100

Minimal inhibitory concentrations (MIC) were determined by the agar dilution method using heart infusion
agar (pH 7.0, 37°C, 20 hrs).

2) Cytotoxicity
IC50 = 0.86 µg/ml (Vero cells), 0.23 µg/ml (Raji cells)

CH3

H3C3) Acute toxicity (mice i.p.)
LD50 = 100 mg/kgO4) Antitumor activity
11,18-Diacetoxydiazaquinomycin A exhibited antitumor activity
against Meth-A fibrosarcoma (10 mg/kg/day, day 1–4, T/C 141%; 100
mg/kg/day, days 1–4, T/C 175%).

AcO

OAcONHNHOO
11,18-Diacetoxydiazaquinomycin A

Ki values of diazaquinomycin A against
5. Mode of action5)
thymidylate synthases
The inhibitory site of diazaquinomycin A was confirmed toKi
be thymidylate synthase. It competitively inhibited bacterial Origin
Enterococcus faecium
36 µM
and mammalian thymidylate synthases.
Ehrlich ascites carcinoma
14 µM
CONHCHCOOH

O

CH2CH2COOH
NO
N

HN
N

H2N

N
H

5,10-Methylene-THF

HNO
HO P O
HOO
O

NdUMP

OH

H3C
O
H3C

Thymidylate synthase

OOO
HN
H2N

N

CHONHCHCHOOH
HN
N
H

CH3

CH2CH2COOH

NH

DHF

CH3HN
O
HO P O
HOO
O
OH

NdTMP

6. References
1. [250] S. Ōmura et al., J. Antibiot. 35, 1425-1429 (1982)
2. [267] S. Ōmura et al., Tetrahedron Lett. 24, 3643-3646 (1983)
3.		
T. R. Kelly et al., Tetrahedron Lett. 29, 3545-3546 (1988)
4. [326] S. Ōmura et al., J. Antibiot. 38, 1016-1024 (1985)
5. [327] M. Murata et al., J. Antibiot. 38, 1025-1033 (1985)
6. [412] K. Tsuzuki et al., J. Antibiot. 42, 727-737 (1989)

CH3
NHO

NHO

Diazaquinomycin A