Isolation of Novel Secondary Metabolites Produced by Fungal Endophyte Isolated from Dead Woody Twigs

FATIMAH AYU W, Prof. Dr. Ganis Lukmandaru, S.Hut., M.Agr.

2020 | Skripsi | S1 KEHUTANAN

Dua senyawa baru bersama dengan tiga senyawa yang telah dikenal diisolasi dari substrat padat kultur jamur endofit yang diperoleh dari ranting berkayu. Penelitian ini bertujuan untuk mengoptimalkan pemanfaatan hasil hutan tanpa menyebabkan eksploitasi berlebihan dengan berfokus pada senyawa berguna yang diproduksi oleh jamur endofit. Penelitian ini juga dilaksanakan guna menyeleksi jamur endofit potensial menggunakan analisis profil TLC, mengisolasi senyawa menggunakan teknik pemisahan kromatografi, dan penentuan struktur senyawa menggunakan analisis spektroskopi. Ranting tumbuhan berkayu tak teridentifikasi dari Universitas Gadjah Mada, Indonesia dan beberapa hutan di Prefektur Yamagata, Jepang dipilih sebagai sumber jamur endofit. Pengumpulan jamur endofit dilakukan berdasar pada kenampakan morfologi tiap jamur setelah masa inkubasi menggunakan tiga jenis media, yaitu PDA, PDA-CS, dan AGS. Dalam penelitian ini diperoleh total sebanyak 524 jamur. Sebanyak 4 jamur dengan produksi metabolit sekunder yang tinggi, persebaran senyawa yang baik, dan warna yang menarik berdasarkan analisis TLC dipilih sebagai jamur potensial. Dari keempat jamur tersebut, jamur HN-1.1 dipilih untuk studi lebih lanjut. Tidak dilakukan identifikasi jamur dalam penelitian ini, tetapi jamur telah diawetkan dan disimpan. Fermentasi, ekstraksi, pemisahan kromatografi, dan karakterisasi metabolit sekunder jamur HN-1.1 menghasilkan tiga senyawa turunan oktahidronaptalen yang telah diketahui, yaitu trichodermic acid (1), trichodermic acid A (2), dan trichodermic acid B (3) dan dua senyawa analog baru (4) dan (5). Struktur senyawa tersebut ditentukan menggunakan analisis data spektroskopik, termasuk 1D- dan 2D-NMR dan data MS. Ditemukannya metabolit sekunder baru ini menunjukkan bahwa kultur jamur endofit merupakan sumber potensial untuk menghasilkan senyawa baru.

Two novel compounds together with three known compounds were isolated from the solid-substrate culture of endophytic fungus from dead woody twigs. This study aimed to deeply optimize forest product utilization without causing overexploitation by focusing on beneficial compounds produced by endophytic fungi. This study was done to screen the potential endophytic fungi by TLC profiling analysis, compound isolation by chromatography separation technique, and structure determination of the compounds by spectroscopy analysis. Unidentified dead twigs of woody plants from Gadjah Mada University, Indonesia and several forests in Yamagata Prefecture, Japan were chosen as sources of endophytic fungi. The collection of endophytic fungi was conducted based on morphological appearance of each fungus after incubation by using three kinds of media including PDA, PDA-CS, and AGS media. In this study, a total of 524 fungi strains were collected. A total of 4 strains with highly produced secondary metabolites, good compound distribution, and interesting color spots based on TLC analysis were selected as potential fungi. From four potential strains, the strain HN- 1.1 was chosen for further study. The strain was not identified here, however, it has been corned and deposited. Fermentation, extraction, chromatography separation, and characterization of secondary metabolites produced by HN-1.1 obtained three known octahydronaphthalene derivative compounds that were trichodermic acid (1), trichodermic acid A (2), and trichodermic acid B (3) and two novel analogue compounds (4) and (5). The structures of those compounds were established by extensive analysis of their spectroscopic data including 1D- and 2D-NMR and MS data. That discovery of new secondary metabolites manifests that endophytic fungal culture is a potential source for producing novel compounds.

Kata Kunci : endophytic fungi, HN-1.1, novel compound, octahydronaphthalene, secondary metabolite, forest chemistry.