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. 2017 Aug 14;22(8):1345.
doi: 10.3390/molecules22081345.

Inhibitors of the Detoxifying Enzyme of the Phytoalexin Brassinin Based on Quinoline and Isoquinoline Scaffolds

M Soledade C Pedras  1 , Abbas Abdoli  2 , Vijay K Sarma-Mamillapalle  3
Affiliations

Inhibitors of the Detoxifying Enzyme of the Phytoalexin Brassinin Based on Quinoline and Isoquinoline Scaffolds

M Soledade C Pedras et al. Molecules. .

Abstract

The detoxification of the phytoalexin brassinin to indole-3-carboxaldehyde and S-methyl dithiocarbamate is catalyzed by brassinin oxidase (BOLm), an inducible fungal enzyme produced by the plant pathogen Leptosphaeria maculans. Twenty-six substituted quinolines and isoquinolines are synthesized and evaluated for antifungal activity against L. maculans and inhibition of BOLm. Eleven compounds that inhibit BOLm activity are reported, of which 3-ethyl-6-phenylquinoline displays the highest inhibitory effect. In general, substituted 3-phenylquinolines show significantly higher inhibitory activities than the corresponding 2-phenylquinolines. Overall, these results indicate that the quinoline scaffold is a good lead to design paldoxins (phytoalexin detoxification inhibitors) that inhibit the detoxification of brassinin by L. maculans.

Keywords: Leptosphaeria maculans; antifungal; brassinin oxidase; camalexin; crucifer; paldoxin; phenylquinoline; phytoalexin detoxification.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
Detoxification of brassinin (1) by BOLm (Leptosphaeria maculans) and inhibitors camalexin (3a), 5-methoxycamalexin (3b), brassilexin (4a) and 6-chlorobrassilexin (4b).
Figure 1
Figure 1
Quinolines 5a–8 and isoquinolines 9a–10b evaluated for inhibition of BOLm.
Scheme 2
Scheme 2
Synthesis of isoquinolines 9a–9c.
Scheme 3
Scheme 3
Synthesis of isoquinolines 10a and 10b.
See this image and copyright information in PMC

References

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