Isolasi dan identifikasi senyawa antifungal dari Acacia mangium Willd. dan uji aktivitasnya terhadap Ganoderma philippii

YUNIARTI, Prof.Dr. S.M. Widyastuti, M.Sc

2008 | Tesis | S2 Bioteknologi

Acacia mangium Willd. (mangium) merupakan spesies cepat tumbuh yang menjadi salah satu jenis utama pada Hutan Tanaman Indonesia. Mangium rentan terhadap fungi patogen busuk akar Ganoderma philippii. Beberapa tanaman keras dilaporkan mengandung sejumlah besar senyawa bioaktif yang memiliki aktivitas biologi yang tinggi, seperti antibakteri, antioksidan dan antifungal. Tujuan penelitian ini adalah untuk mengisolasi dan mengidentifikasi senyawa antifungal dari mangium dan mengetahui aktivitasnya terhadap G. philippii. Informasi ini merupakan bagian dari informasi dasar untuk mengetahui mekanisme ketahanan mangium terhadap G. philippii. Kayu gubal dan teras dari mangium sehat, sakit dan mati dimaserasi dengan n-heksana dilanjutkan dengan metanol. Isolasi antifungal menggunakan metode kromatografi lapis tipis, kromatografi kolom dan kromatografi lapis tipis preparatif. Uji antifungal awal dilakukan menggunakan penghambatan perkecambahan dan panjang buluh kecambah spora Fusarium sp. Identifikasi antifungal menggunakan spektrometri Ultra Violet (UV), Infra Red (IR) dan Gas Chromatography – Mass Spectrometry (GCMS). Aktivitas antifungal terhadap G. philippii diuji menggunakan modifikasi metode cylinder plate secara in vitro. Senyawa antifungal berhasil diisolasi pada fraksi IV3-1 dari ekstrak metanol kayu teras mangium mati. Fraksi IV3-1 menunjukkan penghambatan terbesar terhadap perkecambahan dan panjang buluh kecambah spora Fusarium sp. (64%; 6,4 μm). Zona penghambatan pertumbuhan hifa G. philippii secara makroskopis oleh senyawa antifungal mulai teramati pada konsentrasi 1.000 μg.ml-1 . Secara mikroskopis, pada zona kontak dengan senyawa antifungal, hifa berbentuk keriting dan bercabang pada konsentrasi 800 μg.ml-1. Pada konsentrasi antifungal 1.000-1.500 μg.ml-1, hifa nekrosis dan lisis. Berdasarkan spektra GCMS, antifungal diidentifikasi sebagai triterpenoid glikosida.

Acacia mangium (mangium) is the major fast-growing tree species in Indonesia’s plantation industry. However, this species is susceptible to red root disease caused by the fungus G. philippii. Several hardwood species produce bioactive substances with antimicrobial activities. The main objective of this research was to isolate and identify antifungal compound from mangium and to determine its activity against G. philippii in vitro. This information will partially provide basic information to study the resistance mechanism of mangium to the fungus. Healthy, infected and dead tissue of sapwood and heartwood were separately macerated with n-hexane followed by methanol. Isolation of antifungal compounds were performed using thin layer chromatography (TLC), coloum chromatography and preparative TLC. In the initial bioassay, antifungal activity of selected compounds was indicated by the inhibition of spore germination and germ tube elongation of Fusarium sp. Ultra Violet (UV), Infra Red (IR) and Gas Chromatography – Mass Spectrometry (GCMS) were used to identify the selected compound. The antifungal activity of this compound was tested in the bioassay against G. philippii using modified cylinder plate method. Antifungal compound was successfully isolated from fraction IV3-1 from methanolic extract of dead heartwood tissue. Fraction IV3-1 showed the highest antifungal activity, indicated by spore inhibition (64%) and germ tube elongation of Fusarium sp. (6,4 μm). Inhibition zone was observed macroscopically at the outer colony of G. philippii from antifungal compound at a concentration of 1,000 μg mL-1. Microscopically, on the contact zone with the antifungal compound, hyphae were curly and branched at a concentration of 800 μg mL -1. At a concentration of 1,000-1,500 μg mL-1 of antifungal compound, hyphae were necrotic and lysis. Based on the analysis of GCMS spectra, the antifungal was identified as triterpenoid glycosides.

Kata Kunci : Senyawa Antifungal,Acacia mangium Willd,Ganoderma philippii, antifungal, Acacia mangium Willd., Ganoderma philippii, triterpenoid glycosides