Abstract
Tomato plant is one of the important crops in tropical countries and various bacterial and fungal pathogens affected yield. Among fungal and bacterial pathogens, Pseudomonas syringae affected the leaves of tomato under field and green house conditions and caused bacterial speck disease. The ethyl acetate extract of Albizia lebbeck bark showed maximum zone of inhibition against P. syringae (24 ± 1 mm) and P. corrugate (21 ± 2 mm), and Xanthomonas campestris (21 ± 2 mm), whereas chloroform extract was effective against P. syringae (25 ± 1 mm) and X. campestris (22 ± 2 mm). The MIC value was 250 ± 0 μg/mL (chloroform extract), and 300 ± 25 μg/mL (ethyl acetate extract), respectively against P. syringae. The solvent fractions of A. lebbeck bark extract showed potential antioxidant activity. The cytotoxic effect of the bark extract was concentration dependent, moreover the ethyl acetate extract showed maximum cytotoxic effect and low LC50 value (69.5 μg/mL). A. lebbeck bark extract reduced disease incidence caused by P. syringae in green house (P < 0.05). The bark extract has demonstrated antibacterial activity on phytopathogens and could be used against speck disease in tomato plant.
•Albizia lebbeck bark extract was effective against speck disease causing phytopathogens.•Bark extract increased activity against bacterial and fungal pathogens.•Phenoic and flavonoid contents improved antioxidant potential.•The bark extract showed less cytotoxic effect.•Phytochemicals protected tomato plant against speck disease in greenhouse.