Antibacterial activity of the methanol extracts of two endemic Sideritis species of Turkey against plant pathogenic bacteria

Abstract

Sideritis condensata Boiss. & Heldr. (SC) and Sideritis erythrantha var. erythranthaBoiss. & Heldr (SE) are endemic species in Turkey. The extracts of the endemic species were investigated for antibacterial activity against thirteen plant pathogenic bacteria in vitro by using the agar diffusion method. Statistical differences within bacteria were important at p < 0.05. SC extract was more effective than the SE extract. The total phenolics were found as 247.62 ± 1.91 mg gallic acid equivalent (GAE)/g in SC extract and 217.61 ± 0.95 mg GAE/g in SE extract of dried weight. Total yields were found as 4.77±0.93 in SE extract and 6.47 ± 0.95 in SC extract. The SC extracts at 10% concentration were exhibited by the most effective antibacterial effects against Xanthomonas axonopodis pv. vesicatoria,Xanthomonas campestris pv. campestris and Pseudomonas syringae pv.phaseolicola and the less effective against Ralstonia solanacearum, Pseudomonas savastanoi pv. savastanoi, Clavibacter michiganensis subsp. michiganensis,Rhizobium vitis and Rhizobium tumefaciens. On the other hand, SE extracts at 10% concentration were showed less effective than SC extract. 10% concentration of SE extracts was shown to be more effective antibacterial activity against R. vitis. 1% concentration of SE was not shown antibacterial activity againstPectobacterium carotovorum pv. carotovorum, Pseudomonas corrugata, Pseudomonas syringae pv. tomato, R. solanacearum and X. axonopodis pv. vesicatoria. Key words: Sideritis, antibacterial activity, plant pathogenic bacteria.