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Abstracts - Lucas Cintra

Type of the Presentation: Poster

ANTIMICROBIAL ACTIVITY OF THE LICHEN USNEA STEINERI AND ITS MAJOR METABOLITE USNIC ACID AGAINST PHYTOPATOGENS

Lucas Cintra*, Lúzio G. B. Flauzino, Daiane F. Galvão Sampaio, Maria Anita L. Vasconcelos, Ana Helena Januário, Patricia M. Pauletti, Márcio L. Andrade e Silva, Carlos H. Gomes Martins, Wilson Roberto Cunha

Universidade de Franca;

*Correspondence: lscintra@uol.com.br

In the search for substitutes for synthetic compounds used to control diseases in agriculture, natural products are an alternative of economic and ecological interest very promising, where the use of compounds extracted of natural sources with a possible activity on phytopathogens inhibition could represent an option in the control of diseases in the field. In this study, we evaluated the antimicrobial activity of extract and isolated compound of Usnea steineri against six phytopathogens. A phytochemical study of the acetone extract of U. steineri was conducted and (+)-usnic acid was isolated as the main compound. The minimum inhibitory concentration (MIC) values were determined by using the broth microdilution method in 96-well microplates1. A solid dispersion (SD) containing 10% of usnic acid also was prepared and tested. The results for the antimicrobial activity are displayed in Table 1. Usnic acid showed activity against Pestalotiopsis sp and the use of dispersion solid can be a good strategy for diminution of the concentration of the active compound. (Financial support: CNPq and FAPESP).

Table 1. Antimicrobial activity of the acetone extract, usnic acid and SD of usnic acid against phytopathogens.

Minimum inhibitory concentration in µg.mL-1

Microorganisms

Samples

 

Acetone Ext.

Usnic acid

SD usnic acid

 

Macrophomina phaseolina

 

2000

500

1000

 

Fusarium solani

 

2000

2000

1000

 

Pestalotiopsis sp

 

>2000

31.25

62.5

 

Lasiodiplodia theobromae

 

2000

2000

2000

 

Rhizoctonia solani

 

>2000

>2000

>2000

 

Rhizoctonia solani

 

>2000

2000

1000

 

Refs.1. CLSI - Clinical and Laboratory Standards Institute (2006) Approved Standard. Document M7-A7.