In vitro antibacterial activity and phytochemical profiling of Indonesian Anacardium occidentale L. leaf extract and fractions

Context: Uncontrolled practice of antibiotics leads to bacterial resistance. Therefore, investigating the possible utilization of several medicinal plant extracts is necessary. Traditionally, numerous medicinal plants have been widely utilized to treat some human diseases includingAnacardium occidentale. Aims: To investigate the antibacterial activity of the ethanolic extract and fractions from A. occidentale as well as characterize the phytochemical profile of A. occidentale leaves associated with antibacterial capacity. Methods: The antibacterial activity was determined using minimum inhibitory concentration and time kill assay, which confirmed by streak agar plate. Phytochemical profiling of A. occidentale leaves extract and fractions were evaluated by their total phenolic contents, total flavonoid contents, terpenoid contents, and metabolite analysis by UHPLC-HR-ESI-MS. Results: Among the extract and all fractions, the ethyl acetate fraction had high killing efficiency against Staphylococcus aureus, Bacillus subtillis, Escherichia coli, and Pseudomonas aeruginosa, which was confirmed by its MIC value of 0.5, 0.5, 0.5, and 0.25 mg/mL, respectively. Corresponding to its antibacterial capacity, the ethyl acetate fraction showed the highest of phenolic (508.89 mg GAE/g dw) and flavonoid (184 mg QE/g dw) contents. Based on HRMS investigation, the extract and fractions contain amino acids, phenolic acids, alkaloids, flavonoids, fatty acid amides, fatty acids, and organic acids as classes of molecules. Moreover, avicularin/quercetin-3-O-arabinofuranoside, myricitrin, and gallic acid were identified as major compounds from the active fraction. Conclusions: The ethyl acetate fraction showed the most remarkable antibacterial activity. There was a significant correlation between the antibacterial activity of active fraction and its phenolic and flavonoid contents.