Investigation of the chemical composition of antibacterial Psidium guajava extract and partitions against foodborne pathogens.

P. guajava was partitioned into aqueous and ethyl acetate fractions and studied for its antibacterial chemical constituents. The minimum inhibitory concentrations of the aqueous and ethyl acetate partitions against Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus were found to be 0.75, 0.75, 0.15, 0.5, 0.5, and 0.125%, respectively. Using LC-MS-based chemical fingerprinting, auto MS/MS fragmentation and bioactive molecular networking, 18 compounds of interest were detected. The top 10 bioactive compounds and eight additional non-bioactive compounds known to be found in P. guajava are highlighted. We report five compounds to be identified in P. guajava for the first time. Studies have indicated P. guajava to be a plant source of antibacterial compounds that could be useful in the food industry to prevent foodborne illnesses outbreaks, reduce food spoilage, and satisfy consumer demands for less synthetic chemical usage in the food industry.

Bioactive Natural Products Identification Using Automation of Molecular Networking Software.

Secondary metabolites from natural sources are promising starting points for discovering and developing drug prototypes and new drugs, as many current treatments for numerous diseases are directly or indirectly related to such compounds. Recent advances in bioinformatics tools and molecular networking methods have made it possible to identify novel bioactive compounds. In this study, a workflow combining network-based methods for identifying bioactive compounds found in natural products was streamlined by innovating an automated bioinformatics software. The workflow relies on Global Natural Product Social Molecular Networking (GNPS), a web-based mass spectrometry ecosystem that aims to be an open-access knowledge base for community-wide organization and sharing of raw, processed, or annotated fragmentation mass spectrometry data. By combining computational tools including MZmine2, GNPS, and Cytoscape, the integrated dashboard quickly creates bioactive molecular networks with minimal user intervention and reduces the processing time of the original workflow by over 80%. This newly automated workflow quickens the process of discovering bioactive compounds from natural products. This study uses extracts from Psidium guajava leaves to demonstrate the application of our automated software.