Evaluation of antimicrobial potential and phytochemicals in Acmella ( A. oleracea ) flower pod extracts subjected to different drying techniques

Abstract

The study was aimed to evaluate how drying methods and extracting solvents can preserve antimicrobial properties of Acmella flower pods. Four drying techniques (sun drying [SD], air drying [AD], oven drying [OD], and cooling with dehumidifying [CWD]) and three different solvent extractions (ethanol extracts [EE], water extracts [WE], and pet ether extracts [PEE]) were employed to evaluate extraction yield (EY), phytochemical analysis, and in vitro antibacterial activity. The highest EY was observed in CWD dried WE. Alkaloids, tannin, and quinone were detected in all extracts while flavonoid only in SD and CWD dried EE. CWD dried WE comprised all tested phytochemicals, except flavonoids. CWD dried WE showed higher zones of inhibitions (ZOI) 18.8, 14.0, 12.0, 20.2, and 17.3 mm for Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans, respectively. CWD dried pod extracts showed higher effectivity against bacteria and fungus while lowest given by SD extracts. CWD dried WE gave 20 volatile compounds in GC-MS, including dilauryl thiodipropionate, clionasterol, and spilanthol. Practical applications This study provided a comprehensive evaluation of how the drying method and solvent used for extraction of Acmella oleracea flower pods can effect on the extraction yield, available phytoconstituents, and antimicrobial activity. Through this study, it was recognized that CWD drying followed by water extraction is the best method to preserve antimicrobial potential and bioactive constituents in preserving raw Acmella oleracea flower pods. Phytochemical availability and ability to inhibit Gram-negative, positive bacteria, and fungus is an indication of Acmella flower pods' antimicrobial potential which can be employed to control food pathogenic microorganisms in food industry.