Antimycobacterial Activity and MIC–MBC Determination of Clerodendrum minahassae Ethanolic Leaf Extract Against Mycobacterium smegmatis / Aktivitas Antimikobakteri serta Penentuan MIC–MBC Ekstrak Etanol Daun Clerodendrum minahassae terhadap Mycobacterium smegmatis

Tuberculosis remains a major global health challenge, particularly due to the increasing emergence of drug-resistant strains, highlighting the need for new antimycobacterial agents from natural sources. Clerodendrum minahassae, a medicinal plant traditionally used in North Sulawesi, has demonstrated antibacterial activity; however, its antimycobacterial potential has not been previously explored. This study aimed to evaluate the antimycobacterial activity of the ethanolic leaf extract of C. minahassae against Mycobacterium smegmatis as a surrogate model and to estimate its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The extract was tested at concentrations of 5, 7.5, and 10 µg/disc using the disc diffusion method. Inhibition zone diameters increased in a concentration-dependent manner, ranging from 9.40 ± 0.52 mm to 10.60 ± 0.92 mm. Quantitative analysis using Bloomfield-based linear regression revealed a strong dose–response relationship (R² = 0.9926), from which MIC and MBC values of 0.63 µg/disc and 2.52 µg/disc were estimated, respectively. These findings indicate that the ethanolic extract of C. minahassae exhibits measurable inhibitory and bactericidal activity against M. smegmatis at relatively low concentrations. While this study represents an exploratory screening, the results support the potential of C. minahassae as a source of bioactive compounds with antimycobacterial relevance. Further investigations involving fractionation, compound identification, toxicity assessment, and validation against pathogenic Mycobacterium tuberculosis strains are warranted.

Tuberkulosis masih menjadi tantangan kesehatan global, terutama akibat meningkatnya kasus resistensi obat, sehingga diperlukan pencarian agen antimikobakteri baru berbasis bahan alam. Clerodendrum minahassae, tanaman obat yang digunakan secara tradisional di Sulawesi Utara, telah dilaporkan memiliki aktivitas antibakteri, namun potensi antimikobakterinya belum banyak diteliti. Penelitian ini bertujuan untuk mengevaluasi aktivitas antimikobakteri ekstrak etanol daun C. minahassae terhadap Mycobacterium smegmatis sebagai organisme model, serta mengestimasi nilai MIC dan MBC. Ekstrak diuji pada konsentrasi 5, 7,5 dan 10 µg/disc menggunakan metode difusi cakram. Diameter zona hambat meningkat seiring kenaikan konsentrasi ekstrak, dengan rentang 9,40 ± 0,52 mm hingga 10,60 ± 0,92 mm. Analisis kuantitatif menggunakan regresi linear berbasis metode Bloomfield menunjukkan hubungan dosis–respon yang sangat kuat (R² = 0,9926), yang digunakan untuk mengestimasi nilai MIC sebesar 0,63 µg/disc dan MBC sebesar 2,52 µg/disc.
Hasil penelitian ini menunjukkan bahwa ekstrak etanol C. minahassae memiliki aktivitas penghambatan dan bakterisidal yang terukur terhadap M. smegmatis pada konsentrasi relatif rendah. Meskipun bersifat eksploratif, temuan ini mendukung potensi C. minahassae sebagai sumber senyawa bioaktif dengan relevansi antimikobakteri. Penelitian lanjutan diperlukan untuk fraksinasi terpandu bioaktivitas, identifikasi senyawa aktif, evaluasi toksisitas, serta validasi terhadap strain patogen Mycobacterium tuberculosis.