HPLC-DAD phenolic profiles, antibiofilm, anti-quorum sensing and enzyme inhibitory potentials of Camellia sinensis (L.) O. Kuntze and Curcuma longa L.

Abstract

This study aimed at investigating phenolic composition, anti-quorum sensing and enzyme inhibitory potential of Camellia sinensis and Curcuma longa. HPLC-DAD identified and quantified curcumin (398.67 ± 0.34 mg/g), demethoxycurcumin (261.39 ± 0.27 mg/g) and bisdemethoxycurcumin (173.32 ± 0.46 mg/g) in C. longa extract and eight phenolics in C. sinensis with major components epigallocatechin (365.53 ± 0.49 mg/g), epicatechin (324.05 ± 0.37 mg/g) and epicatechin gallate (94.48 ± 0.27 mg/g). Seven pathogenic microorganisms (Escherichia coli, Listeria monocytogenes, Enterococcus faecalis, Salmonella typhi, Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa) were subjected to antimicrobial and antibiofilm assays and lowest MIC values were 0.3125 mg/mL exhibited by Camellia sinensis on S. aureus and Curcuma longa on P. aeruginosa. At MIC and sub-MIC concentrations, extracts displayed excellent antibiofilm activities especially at MIC concentrations and S. aureus was most susceptible to extracts of C. sinensis (80.56 ± 1.16%) and C. longa (75.79 ± 0.58%). Extracts exhibited concentration-dependent percentage inhibitions of motility and violacein production but only C. longa displayed good antiquorum sensing activity at MIC (18.6 ± 3.0 mm) and MIC/2 (14.5 ± 0.2 mm). C. longa extract disrupted signal reception by CV026 of externally supplied acyl homoserine lactone within revealed anti-quorum sensing zones. Extracts displayed moderate anticholinesterase, anti-urease and anti-tyrosinase activities. Both food extracts can control foodborne infections. © 2020 Elsevier Ltd