Antimicrobial activity in vitro of extracts leaf Guazuma ulmifolia Lam. over phytopathogens

Abstract

Currently it is looking for a biological control of pathogens microorganisms, with plant-derived substances. The (Guazuma ulmifolia) is a tree with pesticide properties and healing effects. Yield, antifungal and antibacterial activity of extracts obtained with buffering solutions (peptides) and organic solvents (metabolites) from guacima leaves were evaluated. The peptides were extracted with buffers: B1 (pH 7.0) KCl, EDTA; B2 (pH 5.2) KCl, CH3COONa, β-mercaptoethanol; and B3 (pH 7.0) KCl, EDTA, phenylmethylsulfonyl fluoride (PMSF), polyvinylpyrrolidone, thiourea, while metabolites were extracted with hexane, methanol and dichloromethane. Protein concentration was made by the Bradford method and the molecular weight by polyacrylamide gel electrophoresis. Thin layer chromatography (TLC)-Packed column, were sequentially applied to separate the compounds and bio-testing them later. In parallel fungus Sclerotium cepivorum of onion and Fusarium oxysporum of melon, as well as the bacteria Xanthomonas campestris of tomato were isolated, and Pseudomonas aeruginosa was inoculated (registry number 0693-P). Antifungal activity was measured by inhibition of in vitro mycelial growth of microorganisms while the antibacterial activity was evaluated by inhibition of colony formation (CFUmL-1). Relative to extracts yields, buffer 2 (B2) showed the highest value (15.7 %), while extracts in hexane (3.9 %), methanol (3.0 %) and dichloromethane (2.2 %) were lower in this parameter. Furthermore the approximate molecular protein weight was of 24.9 kDa. Also, dichloromethane extract showed the greatest inhibition over Sclerotium (88.4 %), B2 over Fusarium (86.5 %) and hexane extracts also on Xantomonas (84.0 %).