Chemical composition, antibacterial and antioxidant activities of Piper betle and Anethum graveolens essential oils against Methicillin-resistant Staphylococcus aureus clinical isolates.

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infection worldwide due to its antimicrobial resistance. Plant-derived essential oils (EOs) have undergone extensive observational and clinical research to explore their antimicrobial properties. The present study aimed to check mec A positive MRSA isolates using sequencing analysis, determination of chemical composition using gas chromatography-mass spectroscopy (GC-MS), antioxidant, and antimicrobial activity of Anethum graveolens and Piper betle EOs against the infectious agent MRSA. The result demonstrates a significant antibacterial activity of both essential oils against MRSA clinical isolates. GC-MS analysis of Piper betle showed (41.06%) 3-Allyl-6-methoxyphenol (Eugenol) as the major compound, whereas Anethum graveolens exhibited o-cymene (14.01%) abundantly. Piper betle essential oil retained appreciable levels of total phenolic (39.5 ± 10.9 mg/g of gallic acid equivalents) and flavonoid content (216 ± 145 mg quercetin equivalent/g), when compared to Anethum graveolens essential oil. A strong correlation was observed between antioxidant activity (DPPH, FRAP, and ABTS), total phenolic, and total flavonoid content in the Piper betle and displayed using principal component analysis (PCA) and a scatter matrix plot. Parallelly, clear morphological bacterial alterations were visualized by scanning electron microscopy after treating it with essential oils. MRSA showed malformed cell surfaces or broken cells with pore formation and septae. These findings imply that both essential oils are potential natural sources of antimicrobials against the MRSA superbug. They can also be used in combination therapies with other plant EOs or with traditional antibiotics to combat the rise of bacteria resistance.