A promising antibiotic, synergistic and antibiofilm effects of Vernonia condensata Baker (Asteraceae) on Staphylococcus aureus

Abstract

Vernonia condensata Baker is traditionally used to treat several inflammatory and infectious processes. So, this study evaluated the antibiotic, synergistic and antibiofilm effects, and the mode of action of ethyl acetate fraction from V. condensata leaves (Vc-EAF) against Staphylococcus aureus. Five S. aureus ATCC and five methicillin-resistant S. aureus (MRSA) routine strains were used to determine Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration. The combinatory effect was evaluated by checkerboard and time kill methods; the mode of action through the bacterial cell viability and leakage of compounds absorbing at 280 nm; and the antibiofilm action by quantifying the percentage of adhesion inhibition. Vc-EAF was active against S. aureus (ATCC 6538), (ATCC 25923), (ATCC 29213), (ATCC 33591), (ATCC 33592), MRSA 1485279, 1605677, 1664534, 1688441 and 1830466, with MIC of 625 μg/mL for ATCC, and 1250, 1250, >2500, 2500 and 2500 μg/mL for MRSA, in this order, with bacteriostatic effect for both ATCC and MRSA strains. Vc-EAF plus ampicillin revealed a total synergic effect on MRSA 1485279, and Vc-EAF combined with chloramphenicol, a partial synergic action against S. aureus (ATCC 29213) and (ATCC 25923). The time kill data agreed with checkerboard results, and the treated cells number was reduced with release of bacterial content. An expressive bacterial adhesion inhibition for S. aureus (ATCC 25923) and MRSA 1485279 was detected. These results showed that V. condensata is a promising natural source of active substances against S. aureus, including multiresistant strains, interfering with their antibacterial growth and hampering their adhesion to surfaces.

Anti-mycobacterial and anti-inflammatory activity of restinga plants: a dual approach in searching for new drugs to treat severe tuberculosis

“…The extracts and isolated compounds from Vernonia amygdalina Delile flowers showed considerable antibacterial activities against different pathogenic bacteria (Habtamu & Melaku 2018). Vernonia condensata Baker, traditionally used to treat infectious processes and inflammation, also showed promising activity against S. aureus, providing scientific support to ethnopharmacological use (Silva et al 2018).…”

Kalanchoe brasiliensisCambess., a Promising Natural Source of Antioxidant and Antibiotic Agents against Multidrug-Resistant Pathogens for the Treatment ofSalmonellaGastroenteritis

“…The time-kill curves of HEJ70 and HES70 (0.5 × MIC , 1 × MIC , and 1.5 × MIC ) and levofloxacin (LEV) (1 × MIC) were carried out for S. Choleraesuis (ATCC® 10708), S. Typhimurium (ATCC® 13311), and Salmonella spp. 1507708 as recommended by da Silva et al [33]. MHB containing 5 × 10 5 CFU/mL of bacterial cultures and HEJ70 or HES70 or LEV (positive control) were aerobically incubated at 35 ± 2°C.…”

“…Bacterial cell viability in the presence of hydroethanolic extracts and LEV was determined according to da Silva et al [33]. One mL of the subcultured bacterial cells (OD 610 = 0.7) of S. Choleraesuis (ATCC® 10708), S. Typhimurium (ATCC® 13311), and Salmonella spp.…”

The action of phytochemicals in biofilm control

“…Effectively, their use as an alternative and/or complementary natural approach to counteract biofilm infections has emerged as an effective prompt solution. 63,64,251–254 Tables 1 and S1† summarize the antibiofilm reports about phytochemicals and/or plant extracts, conducted from December 2008 to December 2021, as well as the associated interference with specific biofilm targets and related events.…”