Paprika extracts (capsicum annuum) from the north of argentine inhibits the virulence of escherichia coli strains

Abstract

The production of protective biofilm (B) and the ability to move dueswarming motility, suggest to Escherichia coli as an important concernin the food industry. Nowadays, the controls of food spoilageinvolve chemical preservatives. However, these compounds are potentiallytoxic. For this reason, spices, generally recognized as safeproducts, are promising alternatives. The aim of this work was to determinethe anti-virulence properties of extracts (E) of paprika (Capsicumannuum) against two strains of E. coli ATCC 35218 and afood isolate LHICA S58. Their inhibition of B was determined by thecrystal violet staining and its metabolism using the MTT assay. Theeffect of E against the bacterial swarming was investigated using theswarm agar method. Five E was obtained: hexane (EH), chloroform(EC), ethyl acetate (EEA), methanol (EM) and total methanol (ETM).The E. coli ATCC 35218 biofilm formation at 24 h was inhibited 86%by the presence of 100 μg/ml of EH. However, nearly all the extractswere able to inhibit the biofilm formation of E. coli LHICA S58, at alower concentration (10 μg / ml). Concerning to the metabolic activityof B cells, for E. coli ATCC, at 10 μg/ml, EH and EC showedsignificant inhibition (p<0.05) and at 100 μg/ml all the extracts hadsignificant activities, above all EH 52% and EC 47%. Against E. coliLHICA all the E at both concentrations showed significant inhibitions(p<0.05) higher than 20%, mainly at 10 μg/ml the EC 40%, EH 36%,and ETM 35%. In addition, the motility of the bacteria was 44% diminishedby 200 μg/ml of EH in the culture collection strain as wellas, 11% and 12% by EC and EM, respectively, in the isolate fromfood. Paprika used as a seasoning and flavoring in several foods isable to control virulence E. coli and could be considered as a promisingnatural preservative and food industry sanitizer.