Bioassay-guided isolation and identification of antibacterial compounds from Piper betle leaf with inhibitory activity against the Vibrio species in shrimp

Abstract

ABSTRACT The present study examined the antimicrobial effects of betel leaf (Piper betle) extracts against Vibrio spp. along with the isolation of the most prevalent bioactive components using a bioassay-guided purification. Following a preliminary screening, the ethanolic extract proved the most effective and performed to silica gel chromatography, followed by reversed phase HPLC to isolate the active components. By means of subsequent UHPLC-orbitrap-ion trap mass spectrometry, two compounds were identified as (E)-3-phenylprop-2-enoic acid (cinnamic acid) and [4-(1-hydroxyprop-2-enyl)phenyl] acetate (1’−hydroxychavicol acetate). The compounds showed anti-microbial activity against Vibrio species including V. parahaemolyticus, V. harveyi, V. alginolyticus, V. vulnificus and V. anguillarum. Their antibacterial action was quantified by a microdilution assay showing that cinnamic acid displays more potent activity (IC50, 21–121 µg/mL) compared to 1’-hydroxychavicol acetate (IC50, 24–365 µg/mL). These findings propose the potential use of the betel leaf as a substitute for antibiotics to combat Vibrio infections in shrimp aquaculture.