Evaluation of antimicrobial activity of glycerol monolaurate nanocapsules against American foulbrood disease agent and toxicity on bees

Abstract

The American Foulbrood Disease (AFB) is a fatal larval bee infection. The etiologic agent is the bacterium Paenibacillus larvae. The treatment involves incineration of all contaminated materials, leading to high losses. The Glycerol Monolaurate (GML) is a known antimicrobial potential compound, however its use is reduced due to its low solubility in water and high melting point. The nanoencapsulation of some drugs offers several advantages like improved stability and solubility in water. The present study aimed to evaluate the antimicrobial activity against P. larvae and the toxicity in bees of GML nanoparticles. The nanocapsules were produced and presented mean diameter of 210 nm, polydispersity index of 0.044, and zeta potential of -23.4 mV demonstrating the acceptable values to predict a stable system. The microdilution assay showed that it is necessary 142 and 285 μg/mL of GML nanocapsules to obtain a bacteriostatic and bactericidal effect respectively. The time-kill curve showed the controlled release of compound, exterminating the microorganism after 24 h. The GML nanocapsules were able to kill the spore form of Paenibacillus larvae while the GML do not cause any effect. The assay in bees showed that the GML has a high toxicity while the GML nanoparticles showed a decrease on toxic effects. Concluding, the formulation shows positive results in the action to combat AFB besides not causing damage to bees.

Insecticidal Action of Glycerol Monolaurate against the Lesser Mealworm (Alphitobius diaperinus) and its Ecotoxicological Effect on Enchytraeus crypticus

“…In this study, GML treatment exerted larvicidal and insecticidal action in vitro against A. diaperinus, similarly to what was observed by researchers against bees [10], where this product was able to eliminate 55% of the bees after 120 h of treatment. It is important to emphasize that the aim of the study was to investigate toxic effects of GML against the bees [10], and not properly its insecticidal action. GML insecticidal mechanism of action is poorly investigated and remains unknown.…”

“…Thus, is important the search of new methods to control the mealworm [2]. The use glycerol monolaurate (GML) in order to control mealworms it's a hypothesis, since this product showed insecticidal effect against bees [10]. The GML is a natural compound found in milk, coconut and palm oils, and other oils derived from lauric acid [9,10].…”

“…The use glycerol monolaurate (GML) in order to control mealworms it's a hypothesis, since this product showed insecticidal effect against bees [10]. The GML is a natural compound found in milk, coconut and palm oils, and other oils derived from lauric acid [9,10]. This product acts as a preservative inhibiting the proliferation of pathogens and avoiding food contamination [1,13].…”

Acute toxicity and antimicrobial activity of leaf tincture Baccharis trimera (Less)

“…aeruginosa PAO1. The method used to this assay was described previously [23] with modifications. To biofilm formation, fresh exponentially grown culture of P. aeruginosa was diluted to be 10 8 CFU/mL, and 20 μL was added to 96-well plates (Nunclon™ D surface, Nunc, Roskilde, Denmark), containing 100 μL of BHI broth.…”

Effects of microbicide based on lactic acid and metal nanoparticles on laboratory animals

“…At the present stage, improvement of the development and introduction of disinfectant with the active substance of lactic acid and nanoparticles of metals, which is an effective fungicide and antiseptic against gram-positive and gram-negative microflora by sanitary and hygiene indices, is carried out (Kotsyumbas et al, 2006;Nikolaenko and Tsapko, 2008;. The study of microbicidal properties of silver nanoparticles and their use to create new complex disinfectants is a promising area of research in many countries around the world (Lopes et al, 2016;Ivask et al, 2014;De Gusseme et al, 2010). At the same time, in the literature there is enough information on the potential toxicity of both silver nanoparticles and other nanoparticles in certain concentrations not only on pathogenic microorganisms, but also on the body of different species of animals (Ivask et al, 2014;Armstrong et al, 2013;Likus et al, 2013).…”