Phytochemical indicators and antibacterial activity of the crude hydroalcoholic extract of Achyrocline satureioides ("macela") against antibiotic-resistant Salmonella spp. isolated from animal products (swine and poultry)

A resistência aos antibióticos, desinfetantes e antissépticos motivam a busca por novos antimicrobianos, tendo-se nas extrações vegetais um potencial bioativo. Os objetivos do trabalho foram testar o extrato hidroalcoólico bruto de A. satureioides frente 51 cepas de Salmonella spp. resistentes a antibióticos isoladas em matéria-prima animal, e detectar compostos fitoquímicos na solução. Foi preparada maceração na proporção 5 g das inflorescências secas : 100 mL de etanol em 70º GL, e após 15 dias o álcool foi removido com evaporador rotativo. Recomposto o volume inicial com água destilada estéril, resultou em extrato bruto na concentração de 50 mg/mL. Foi usado o teste quantitativo europeu de suspensão, confrontando os inóculos nas densidades populacionais (DP) de 107, 106 e 105 UFC/mL, em tempos de contato 5, 15, 60 minutos e de hora em hora até 10 horas. Na DP 107, as 5 h de contato 35% e as 10 h 100% dos isolados estavam inativados; na DP 106 as 5h 39% e as 9 h 100% estavam inativados; na DP 105 as 5 h 51% e as 9 h 100% estavam inativados. Concluiu-se que o extrato bruto inativou todas as cepas de Salmonella spp. resistentes a antibióticos, e que o tempo de contato necessário para a atividade bactericida esteve relacionada com a DP inicial da suspensão e com características intrínsecas dos isolados. A detecção fitoquímica identificou compostos fenólicos como os taninos hidrolisáveis e condensados, flavonóis e saponinas.Resistance to antibiotics, disinfectants and antiseptics motivates the search for new antimicrobials, having in plant extracts a bioactive potential. The objectives of the study were to test the crude hydroalcoholic extract of A. satureioides, against 51 strains of Salmonella spp. resistant to antibiotics isolated from animal raw material, and to detect the phytochemical compounds in the solution. Maceration was prepared in the proportion of 5g of the dried inflorescences: 100 mL of ethanol at 70°GL, and after 15 days the alcohol was removed with rotary evaporator. Recomposing the initial volume with sterile distilled water resulted in the crude extract at a concentration of 50 mg/mL. The European quantitative suspension test was used, comparing the inocula in the population densities (PD) of 107, 106 and 105 CFU/mL, in contact times of 5, 15, 60 minutes, and hourly, up to 10 hours. In the PD 107, in 5 h of contact 35%, and in 10h 100% of the isolates were inactivated; in PD 106, in 5 h of contact 39% and in 9h 100% were inactivated; in the PD 105, in 5 h 51% and in 9h 100% were inactivated. It was concluded that the crude extract inactivated all strains of Salmonella spp. resistant to antibiotics, and that the contact time required for the bactericidal activity was related to the initial PD of the suspension and with the intrinsic characteristics of the isolates. The phytochemical detection identified phenolic compounds such as hydrolysable and condensed tannins, flavonols, and saponins