Electronic Theses and Dissertation

Bakteri endofit merupakan mikroorganisme yang berpotensi menghasilkan metabolit sekunder dengan berbagai aktivitas biologis seperti antioksidan, toksisitas, dan antifungi. Penelitian ini bertujuan menganalisis biopotensi ekstrak bakteri endofit dari tanaman nilam Aceh (Pogostemon cablin Benth. varietas Sidikalang) isolat BEANS, BEBNS, dan BEDNS berdasarkan aktivitas antioksidan, toksisitas, serta profil metabolit sekundernya. Penelitian ini menggunakan metode eksperimental dengan supernatan ketiga isolat sebagai sampel uji. Aktivitas antioksidan dianalisis menggunakan metode 2,2-difenil-1-pikrilhidrazil (DPPH) dan dinyatakan sebagai nilai Inhibition Concentration (IC50 ), sedangkan toksisitas ditentukan menggunakan metode Brine Shrimp Lethality Test (BSLT) untuk memperoleh nilai LC₅₀. Profil metabolit sekunder dianalisis menggunakan Gas Chromatography–Mass Spectrometry (GC-MS). Hasil penelitian menunjukkan bahwa seluruh isolat memiliki aktivitas antioksidan dengan kategori sangat kuat berdasarkan nilai Inhibition Concentration (IC50 ). Isolat BEBNS menunjukkan aktivitas antioksidan tertinggi dengan nilai Inhibition Concentration (IC50 ) sebesar 10,38 ppm, sedangkan isolat BEANS memiliki toksisitas tertinggi dengan nilai LC₅₀ sebesar 29,88 ppm. Analisis GC-MS menunjukkan adanya beragam senyawa metabolit sekunder yang diduga berkontribusi terhadap aktivitas biologis masing-masing isolat. Dengan demikian, bakteri endofit dari tanaman nilam Aceh berpotensi sebagai sumber metabolit sekunder bioaktif yang prospektif untuk dikembangkan lebih lanjut sebagai bahan baku pada bidang farmasi, kesehatan, dan bioteknologi. Kata kunci: Aktivitas antioksidan; Brine Shrimp Lethality Test (BSLT); DPPH; GC-MS; Pogostemon cablin.

Endophytic bacteria are microorganisms that have the potential to produce secondary metabolites with various biological activities, such as antioxidant, toxic, and antifungal properties. This study aims to analyze the biopotential of endophytic bacterial extracts from Aceh patchouli (Pogostemon cablin Benth., Sidikalang variety) isolates BEANS, BEBNS, and BEDNS based on their antioxidant activity, toxicity, and secondary metabolite profiles. The study employed an experimental method using the supernatants of the three isolates as test samples. Antioxidant activity was analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and expressed as the Inhibition Concentration (IC50 ) value, while toxicity was determined using the Brine Shrimp Lethality Test (BSLT) to obtain the LC₅₀ value. The secondary metabolite profile was analyzed using Gas Chromatography–Mass Spectrometry (GC-MS). The results showed that all isolates exhibited very strong antioxidant activity based on their Inhibition Concentration (IC50 ) values. The BEBNS isolate exhibited the highest antioxidant activity with an Inhibition Concentration (IC50 ) value of 10.38 ppm, while the BEANS isolate exhibited the highest toxicity with an LC₅₀ value of 29.88 ppm. GCMS analysis revealed the presence of various secondary metabolites that are believed to contribute to the biological activity of each isolate. Thus, endophytic bacteria from Acehnese patchouli plants have the potential to serve as a source of bioactive secondary metabolites that are promising for further development as raw materials in the pharmaceutical, health, and biotechnology sectors. Keywords: Antioxidant activity; Brine Shrimp Lethality Test (BSLT); DPPH; GC-MS; Pogostemon cablin.