Assessment of the Antibacterial, Antioxidant, and Phytochemical Potential of Fernandoa Adenophylla, Curcuma Caesia, and Melaleuca Alternifolia

Abstract

This study evaluates the antibacterial, antioxidant, and phytochemical profiles of three medicinal plants: Karenwood (Fernandoa adenophylla), Black Turmeric (Curcuma caesia), and Tea Tree (Melaleuca alternifolia) oil. Extracts were prepared using various solvents (aqueous, n-hexane, and ethanol) and subjected to preliminary phytochemical screening, quantitative estimation of total phenolics and flavonoids, and in vitro antioxidant assays including DPPH, ABTS, and hydrogen peroxide scavenging. Antibacterial activity was assessed against six bacterial strains, including Staphylococcus aureus and Escherichia coli, using the agar-cup plate method. Phytochemical analysis revealed diverse secondary metabolites across the species, including flavonoids, tannins, terpenoids, and alkaloids. Quantitative results indicated that the ethanolic extract of C. caesia (CCE3) contained the highest total phenolic content (308.570 ±6.088 µg/ml) and demonstrated superior antioxidant potency in DPPH and ABTS assays. While Tea Tree Oil (TTO) exhibited the highest total flavonoid content (840 ±0.025µg/ml), it also emerged as the most potent antimicrobial agent, showing the largest Zones of Inhibition (ZOI) against P. aeruginosa (15 mm) and E. coli (14 mm). These findings reinforce the therapeutic potential of C. caesia and M. alternifolia as natural sources of antioxidants and antimicrobials, driven by their rich phenolic and terpenoid profiles.