Phytochemical characterization, antibacterial, and anti-biofilm efficacy of Mangifera indica seed kernel: A preliminary study using in vitro and in silico approaches

Abstract

Biofilm-formation is one of the most important virulent factors in the pathogenesis of urinary tract infections. Biofilm is a complex microbial population protected by exopolysaccharides (EPS), which presents with adaptive resistance against antimicrobials. In the current study, we aimed to evaluate the efficacy of a methanolic extract of Mangifera indica seed kernels (MISK) against uropathogenic bacteria collected from urine samples. In total, n = 21 uropathogenic Escherichia coli (UPEC) strains were identified from n = 30 urine samples. Among the n = 21 strains, n = 17 E. coli strains were biofilm-producers in different in vitro model systems (tube-based method, microtiter-plate based method, Congo Red Agar, EPS production). Uropathogens were identified by traditional microbiological methods. MISK is a potential natural source of phytochemicals such as carbohydrates, proteins, stearic and linoleic acids. In the present study, 50 μg/mL and 100 μg/mL of methanolic extract of MISK exhibited prominent antibacterial and anti-biofilm activity against the clinical UPEC strains. In addition, qualitative phytochemical characterization of methanolic extract of MISK showed the presence of bioactive compounds such as tannins, saponins, flavonoids, terpenoids, alkaloids, carbohydrates, polyphenols, and glycosides. Moreover, the characterization of the methanolic extract by UV–VIS, FTIR, and GC–MS analysis confirmed the presence of a phenolic profile, namely mangiferin (1,3,6,7-tetrahydroxyxanthone-C2 -β-D-glucoside). Furthermore, in silico analysis was also investigated to validate that mangiferin can bind to the specific active sites of CAMP LpxC in E. coli. Based on the collective findings of our in vitro and in silico analyses, mangiferin may be the principal compound responsible for the anti-bacterial and anti-biofilm effects of the extract.

Keywords

• Urinary tract infections
• Escherichia coli
• Antimicrobial
• Anti-biofilm
• Mangiferin
• Phytochemicals