Anti-Methicillin-Resistant Staphylococcus aureus Activities of Artocarpus lakoocha Roxb Extract and Its Mode of Action

Abstract

Antibacterial activities and mode of action of Artocarpus lakoocha Roxb extracts against methicillin-resistant Staphylococcus aureus (MRSA) were evaluated, with its biological properties including antioxidant activity and total phenolic content also measured. Heartwoods of A. lakoocha Roxb were extracted by solvents including water, ethanol, acetonitrile, ethyl acetate, isopropanol, and hexane. Results showed that antibacterial activity against MRSA, antioxidant activity, and total phenolic content were highest in the acetonitrile extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 312.5 and 625.0 μg/mL, respectively. Time-killing evaluation indicated a bactericidal mode of action with IC50 values against ABTS and DPPH radicals of 2.37 ± 0.09 and 32.10 ± 0.74 mg/mL, respectively, and total phenolic content 455.29 ± 18.35 mg GAE/g extract. Results suggested that acetonitrile extract of A. lakoocha Roxb had good potential activity against MRSA, with promise for further development as a novel alternative drug.

In Vitro Antibacterial Activity and Mode of Action of Piper betle Extracts against Soft Rot Disease-Causing Bacteria

“…The most suitable extraction solvent for obtaining the highest anti- ECC property was ethanol, with a polarity less than that of water but higher than that of hexane. This result indicated that the extraction solvent also plays an important role in the isolation of active components from plants and was supported by earlier studies that determined organic solvents to be typically more effective at extracting antimicrobial compounds than aqueous-based techniques [ 14 , 17 ]. Ethanol extracts from P. betle also demonstrated excellent antibacterial properties over Gram-positive and Gram-negative bacteria, including those classified as multidrug resistant such as metallo- β -lactamase-producing P. aeruginosa and A. baumannii , MRSA, and VRE [ 14 ].…”

“…This result concurred with previous studies indicating that plant crude extracts had bactericidal or bacteriostatic properties. The mode of action of the antibacterial agents was identified using the MBC/MIC ratio or time-kill kinetic [ 17 , 25 , 26 ]. If the ratio of MBC/MIC is ≤4, it is defined as a bactericidal agent, with a bacteriostatic mode of action considered when the ratio is ≥4.…”

“…One benefit of employing crude plant extracts to suppress pathogenic bacteria is that numerous active ingredients provide a variety of antibacterial actions. A combination of active ingredients is difficult for bacteria to resist; however, synthetic antibacterial agents typically cause bacteria to evolve resistant mechanisms [ 17 ]. Our results indicated that the active constituents against ECC growth found in P. betle showed moderate hydrophilic properties.…”

“…The sample was dried in a hot air oven at 60°C for 3 days before milling. Ground samples were extracted with water, ethanol, and hexane at a ratio of 1 : 10 (sample: solvent) on an orbital shaker at 150 rpm for 24 hours [ 17 ]. The extracts were filtrated, evaporated at 60°C by a rotary evaporator, and then kept at 4°C for anti- ECC activity testing.…”

“…It enhances compound solubility as it is miscible with water and organic solvents, and it is not toxic to the test organism [ 18 ]. The agar-disc diffusion method was performed for anti- ECC activity screening according to the method described by Charirak and Ratananikom (2022) with some modifications [ 17 ]. Briefly, sterile blank discs 6 mm in diameter were placed on nutrient agar plates covered with 100 μ L of ECC .…”