Evaluation of antibacterial activity of extract and essential oil of Tagetes patula L. in vitro against Ralstonia solanacearum biovar 2

Abstract

This work aims to assess the in-vitro antimicrobial activity of the essential oil and hydroalcoholic extract of Tagetes patula against Ralstonia solanacearum the causal of potato wilt disease. Providing necessary information on the antimicrobial activity of the extract and essential oil on this phytopathogen, also contributing to knowledge in the phytopathology area. The antimicrobial activity was carried out through dilution both liquid medium and agar (perforation in well) at different concentrations. The content of flavonoids, polysaccharides, tannins and phenols present in the extract was quantified, and the oil was characterized through gas chromatography–mass spectrometry. The majority compound identified in the oil were piperitone (42.95%) and the extract mostly had polysaccharides (1.54 ± 0.18 mg EG/g DE). Both registered a minimum inhibitory concentration bacteriostatic of 50 μg/mL and the half maximal effective concentrations were 306 μg/mL (oil) and 352 μg/mL (extract). The oil had better yield through the dilution method in liquid medium at concentration of 500 μg/mL, and the hydroalcoholic extract had better bactericide yield of 200 μg/mL. It was concluded that the essential oil and hydroalcoholic extract with further applied studies could be a viable and environmentally friendly alternative to control R. solanacearum.