8-Hydroxy-3-Methyl-3,4-Dihydro-1h-Isochromen-1-One from StaticCultures of the Fungus Xylaria Badia

Introduction Xylaria badia is found worldwide. The isolate that was examined for its secondary metabolites was collected from Thailand. Following the isolation and characterisation of a benzoquinone and naphtol glucoside from the first culture of X. badia [1],. This earlier study, generated the interest in a second culture of the fungus to isolate the other secondary metabolites produce by X. badia. The fungus was cultured under similar conditions. The culture medium was harvested and extracted with neat ethyl acetate after the mycelium had been removed by sieving through a muslin. Drying the extract on a rotary evaporator afforded a dark brown gummy solid (5.0 g). TLC studies indicated that the crude solid was a mixture of four components. Materials and Methods The fungus X. badia was cultured on 3% aqueous malt enriched with 6% glucose in four Thompson bottles for eight weeks for the second time. Solvent extraction with neat ethyl acetate and subsequent drying on a rotary evaporator afforded a dark brown gummy solid (5.0 g). TLC studies indicated that this crude extract was a mixture of four components. One of the components gave a dark brown colour on TLC. The dark brown gum was chromatographed over silica gel in a column of size 80 cm x 2.5 cm. The column was eluted with toluene, ethyl acetate and acetic acid (50:49:1) and the eluent collected in volumes of 3.0 ml. Fraction 3 (tubes 55-74) gave a yellowish oil (150 mg), n-hexane (1.0 ml) was added to the oil and warmed to boiling point. The solution was filtered hot and allowed to cool overnight. A white solid (12 mg) was obtained. The solid was recrystallised in the same solvent system to give R-(-)-mellein white crystals (8 mg), C 10 H 10 O 3 ; mp. 48-50 o C, (lit.,[5] 48 o C), m/z 166 (M +), [α] 23

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