Potential Antagonistic Interaction of Methanol Leaf Extract of Impatiens balsamina L. with Five Antibiotics against Staphylococcus aureus ATCC 29213

Impatiens balsamina L. has traditionally been used in Indonesia for treating skin infections and is considered a potential source of antibacterial compounds. However, the interaction between crude plant extracts and antibiotics may not always result in synergistic effects and may instead reduce antibacterial efficacy. This study evaluated the antibacterial activity and potential interaction of methanol leaf extract of I. balsamina with five antibiotics against Staphylococcus aureus ATCC 29213. The antibacterial activity was assessed using well diffusion and paper strip methods. The treatments consisted of 15% I. balsamina leaf methanol extract, 0.025% of each antibiotic, including clindamycin, chloramphenicol, cotrimoxazole, ciprofloxacin, and tetracycline, and their 1:1 combination. The extract alone produced a mean inhibition zone of 10.27±0.216 mm. Clindamycin, chloramphenicol, ciprofloxacin, and tetracycline showed inhibition zones ranging from 19.46±1.732 mm to 22.34±3.021 mm, while cotrimoxazole showed no inhibition zone. The combinations of the extract with clindamycin, tetracycline, chloramphenicol, ciprofloxacin, and cotrimoxazole produced inhibition zones of 19.54±0.155 mm, 18.57±0.422 mm, 16.37±0.879 mm, 13.28±0.257 mm, and 9.76±0.103 mm, respectively. The diffusion-based assays indicated a potential antagonistic interaction between the extract and the tested antibiotics, characterized by combined inhibitory diameters smaller than the additive sum of the individual agents. These findings suggest that the concurrent use of I. balsamina extract and antibiotics should be further evaluated using MIC-based checkerboard assays and Fractional Inhibitory Concentration Index analysis. Potensi Interaksi Antagonis Ekstrak Daun Metanol Impatiens balsamina L. dengan Lima Antibiotik terhadap Staphylococcus aureus ATCC 29213 ABSTRAK: Impatiens balsamina L. secara tradisional digunakan di Indonesia untuk mengobati infeksi kulit dan diketahui memiliki potensi sebagai sumber senyawa antibakteri. Namun, kombinasi antara ekstrak tanaman dan antibiotik tidak selalu menghasilkan efek sinergis, tetapi juga dapat menurunkan efektivitas antibakteri. Penelitian ini bertujuan untuk mengevaluasi aktivitas antibakteri dan potensi interaksi antara ekstrak metanol daun I. balsamina dengan lima antibiotik terhadap Staphylococcus aureus ATCC 29213. Aktivitas antibakteri diuji menggunakan metode difusi sumuran dan paper strip. Perlakuan terdiri atas ekstrak metanol daun I. balsamina 15%, masing-masing antibiotik 0,025%, yaitu klindamisin, kloramfenikol, kotrimoksazol, siprofloksasin, dan tetrasiklin, serta kombinasi ekstrak dan antibiotik dengan rasio 1:1. Ekstrak tunggal menghasilkan rata-rata zona hambat sebesar 10,27±0,216 mm. Klindamisin, kloramfenikol, siprofloksasin, dan tetrasiklin menghasilkan zona hambat sebesar 19,46±1,732 mm hingga 22,34±3,021 mm, sedangkan kotrimoksazol tidak menunjukkan zona hambat. Kombinasi ekstrak dengan klindamisin, tetrasiklin, kloramfenikol, siprofloksasin, dan kotrimoksazol menghasilkan zona hambat masing-masing sebesar 19,54±0,155 mm, 18,57±0,422 mm, 16,37±0,879 mm, 13,28±0,257 mm, dan 9,76±0,103 mm. Hasil uji berbasis difusi menunjukkan adanya indikasi interaksi antagonis antara ekstrak dan antibiotik yang diuji, ditandai dengan diameter hambat kombinasi lebih kecil daripada jumlah aditif dari masing-masing agen secara individu. Temuan ini menunjukkan bahwa penggunaan ekstrak I. balsamina bersamaan dengan antibiotik perlu dikaji lebih lanjut melalui uji MIC, checkerboard assay, dan Fractional Inhibitory Concentration Index