Anti-infective potential of hydroalcoholic extract of peel against gram-negative bacterial pathogens.

extracts have been prescribed in traditional medicine for management of a variety of disease conditions including microbial infections. Generation of scientific evidence for validation of peel extract's anti-pathogenic efficacy is required. Hydroalcoholic extract of peel (PGPE), prepared by microwave assisted extraction method was evaluated for its quorum-modulatory potential against two different human-pathogenic bacteria viz. and . This extract was able to modulate production of quorum sensing-regulated pigments in both these test bacteria at ≥5 μg/ml. Virulence traits of like haemolytic activity, and biofilm formation were negatively affected by the test extract, and it also made more susceptible to lysis by human serum. Antibiotic susceptibility of both test bacteria was modulated owing to pre-treatment with PGPE. Exposure of these test pathogens to PGPE (≥0.5 μg/ml) effectively reduced their virulence towards the nematode . Repeated subculturing of on PGPE-supplemented growth medium did not induce resistance to PGPE in this notorious pathogen, and this extract was also found to exert a post-extract effect on Individual constituent phytocompounds of PGPE were found to be less efficacious than the whole extract. PGPE seemed to interfere with the machinery of and . PGPE also exhibited notable prebiotic potential by promoting growth of probiotic strains- and at ≤50 μg/ml. This study indicates PGPE to be an effective antipathogenic and prebiotic preparation, and validates its therapeutic use mentioned in traditional medicine. This study also emphasizes the need for testing any bioactive extract at broadest possible concentration range, particularly , so that an accurate picture of dose-response relationship can emerge.