Antimicrobial Activity of Tripitsajuk Crude Etract against Escherichia coli and <i>Pseudomonas aeruginosa</i>

The escalating prevalence of antibiotic-resistant gram-negative bacteria necessitates urgent exploration of alternative therapeutic approaches. Tripitsajuk (TPJ), a traditional Thai medicinal formulation containing Myristica fragrans (nutmeg), Oenanthe javanica (water dropwort), and Syzygium aromaticum (clove), has shown promising antimicrobial properties against gram-positive organisms, yet its efficacy against gram-negative pathogens remains uninvestigated. This study evaluated the antimicrobial potential of Tripitsajuk crude extracts against clinically significant gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Plant materials were extracted using two solvent systems: 40% ethanol (TPJHE40) and absolute ethanol (TPJE) through seven-day maceration. Antimicrobial assessment employed the agar well diffusion technique with extract concentrations ranging from 12.5 to 100 mg/mL. Gentamicin served as the positive control, while 10% dimethyl sulfoxide functioned as the negative control. Statistical analysis was performed using one-way analysis of variance followed by Tukey's post-hoc test with significance established at P < 0.05. TPJE extraction yielded 11.228% compared to 9.903% for TPJHE40. Only TPJE exhibited antimicrobial activity against the two tested organisms. Against E. coli, TPJE showed concentration-dependent inhibition from 12.5 mg/mL (12.00±0.00 mm) to 100 mg/mL (17.11±0.11 mm). P. aeruginosa demonstrated greater resistance, responding only to 100 mg/mL (11.44±0.29 mm). TPJHE40 extract failed to produce measurable inhibition zones at any concentration tested. The absolute ethanol extract of Tripitsajuk demonstrated significant antimicrobial efficacy against gram-negative bacteria at high concentrations, with E. coli displaying higher susceptibility compared to P. aeruginosa. These findings establish Tripitsajuk as a promising candidate for development into adjunctive or alternative antimicrobial therapeutics, particularly for managing drug-resistant gram-negative bacterial infections. Keywords: