Isolasi, identifikasi dan penetapan kadar senyawa antifungal akar acacia mangium serta aktivitasnya terhadap Ganoderma sp

HIDAYATI, Nur, Prof. Dr. Ir.S.M. Widyastuti, M.Sc

2010 | Tesis | S2 Bioteknologi

Acacia mangium Willd. (mangium) adalah salah satu tanaman utama dalam program pembangunan Hutan Tanaman Industri (HTI). Saat ini Ganoderma sp. dilaporkan banyak menyerang pertanaman HTI mangium terutama di Sumatera dan Kalimantan. Mangium yang tahan terhadap Ganoderma sp. belum diketahui. Tujuan dari penelitian ini adalah untuk (1) mengisolasi dan mengidentifikasi senyawa yang bersifat antifungal dari akar mangium sehat, (2) mengetahui aktivitas dan kadar senyawa antifungal dari akar mangium sehat terhadap Ganoderma sp. Penelitian ini menggunakan materi berupa akar mangium sehat dari kebun benih mangium generasi pertama di Wonogiri Jawa Tengah. Akar mangium yang telah dipisahkan antara bagian luar dan bagian dalam dimaserasi dengan pelarut n-heksana dan metanol. Isolasi senyawa antifungal menggunakan metode kromatografi lapis tipis, kromatografi kolom dan kromatografi lapis tipis preparatif. Uji aktivitas antifungal dilakukan dengan menggunakan penghambatan perkecambahan dan penghambatan buluh kecambah Fusarium sp. Identifikasi senyawa dengan analisis spektrometri Ultra violet (UV), Infrared (IR) serta Gas Chromatography-Mass Spectrometry (GC-MS). Uji aktivitas antifungal terhadap Ganoderma sp. dilakukan dengan modifikasi metode cylinder plate secara in-vitro. Penetapan kadar senyawa antifungal dilakukan dengan KLT - densitometer terhadap enam nomor famili pohon yang berbeda. Senyawa antifungal berhasil diisolasi dari substansi B ekstrak metanol akar mangium sebelah dalam. Substansi B menunjukkan aktivitas antifungal tertinggi pada penghambatan kecambah sebesar 66,67% dan penghambatan pembentukan buluh kecambah konidia Fusarium sp. tertinggi sebesar 66,03%. Zona penghambatan pertumbuhan hifa Ganoderma sp. secara makroskopis oleh senyawa antifungal teramati pada konsentrasi 1800 μg/mL. Secara mikroskopis, pada daerah kontak dengan senyawa antifungal, hifa menyimpang serta berbentuk ikal pada ujungnya pada konsentrasi 1500 μg/mL sehari setelah aplikasi senyawa antifungal. Hasil identifikasi dengan GC -MS, senyawa antifungal ini teridentifikasi sebagai p-Methoxybenzylidene p-aminophenol termasuk dalam golongan senyawa fenolik. Hasil dari penetapan kadar dengan metode KLT densitometer mengindikasikan bahwa kadar tertinggi ditunjukkan oleh nomor famili pohon 44 (40,52% b/b) dan kadar terendah ditunjukkan oleh nomor famili pohon 67 (19,88% b/b).

Acacia mangium has been planted on large scale of industrial forest plantation in Indonesia, especially in Sumatera and Kalimantan islands. It has been reported that huge number of mangium plantations on those areas infected rot root disease caused by Ganoderma sp. To date, there was no information of mangium which resist to Ganoderma sp. Moreover, research to get this information had been carried out with two aims as listed below: (1) isolate and identify a compound with antifungal properties from the roots of healthy mangium, and (2) identify the effect and concentration of the antifungal compound from roots of healthy mangium on Ganoderma sp. The roots of healthy mangium from the first generation of seedling seed orchard in Wonogiri, Central Java, were used as material of this research. Mangium roots which had had their external and internal parts separated were macerated in a solvent of nhexane and methanol. Methods of the isolation of the antifungal compound were the thinlayer chromatography (TLC), column chromatography and thin layer preparative chromatography. Antifungal effect test was carried out by using inhibition of germination and of hyphal growth of Fusarium sp. Ultraviolet (UV) spectrometry, Infrared (IR) and Gas Chromatography – Mass Spectrometry (GC-MS) were used to identify the antifungal compound. Antifungal effect test on Ganoderma sp. was done with a modification of the cylinder plate method, performed in vitro. Determination of the concentration of the antifungal compound was done by a TLC densitometer on six different families of trees. The results revealed that the antifungal compound succeed isolated in its Substance B form from methanol extract from the interior of the root. Substance B showed the highest level of antifungal activity through inhib iting germination and inhibiting of germination tube growth of Fusarium sp. This was shown by the highest percentage inhibiting of germination (66,67%), and the highest percentage inhibiting of germination tube (66,03%). The inhibition zone of hyphal growth of Ganoderma sp. macroscopically from the antifungal compound was observed at a concentration of 1800 μg/mL. Microscopically, in the area of contact with the antifungal compound, hyphal curling and distorting of tips took place at a concentration of 1500 μg/mL one day after application of the antifungal compound. Based on the analysis of GC-MS spectra, the antifungal was identified as p-Methoxybenzylidene p-aminophenol in the category of phenolic compounds. Results of identification with the TLC densitometer method showed that among the six families of trees, number 44 had the highest concentration at 40,52% w/w and number 67 showed the lowest concentration at 19,88% w/w.

Kata Kunci : Acacia mangium,Senyawa antifungal,Ganoderma sp