Thin Layer Chromatography‐Bioautography and Gas Chromatography‐Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug‐Resistant Bacteria

Abstract

This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with R f values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with R f values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an R f value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs.

Antimicrobial activity and phytochemical screening of Alpinia malaccensis (Ran-kiriya) against food-borne bacteria

“…This methodology has been considered as the most efficacious assay for the detection of antimicrobial compounds (Valle et al . ) due to its high sensitivity. However, applicability was limited to some micro‐organisms that easily grow on TLC plates.…”

Antibacterial activity of ethanolic extracts from Zingiber zerumbet rhizome against Salmonella spp.

“…The extract components were identified based on comparison of the relative GC retention time and mass spectrum with components from NIST MS Search Library Software version 2.0. Cat 10 ° C/min (Valle et al 2016).…”

Identification and Evaluation of Antibacterial Compounds from the Vibrio sp. associated with the Ascidian Pycnoclavella diminuta

“…Antibacterial activity of the fraction was carried out using the bioautography technique as previously described by Valle Jr et al (2016) with slight modifications. The fractions were spotted on the GF 254 silica gel TLC plate and eluted with three different eluent systems as follows: FA (n-heksan:CHCl 3; 3,5:1,5), FB (CHCl 3 :Acetone; 4:1), FC and FD (CHCl 3 :MeOH; 4,5:1,5).…”