RESUMO

Ganoderma P. Karst. (Ganodermatales, Basidiomycetes) is a cosmopolitan genus of wood decaying polypore mushrooms. In the Orient, Ganoderma species are used in folk medicine for treating several diseases, and some strains are commercially cultivated for medicinal use. The pharmacological effects of the Ganoderma species are attributable mainly to polysaccharides and triterpenoids. G. australe is a common species on the Santa Catarina Island (southern Brazil). Literature is scarce on the chemical composition of this species and also on studies relating substances produced by G. australe and their biological activity. A methanol extract from the basidioma of this species was obtained, which was partitioned successively with hexane, chloroform, and ethyl acetate. These extracts were fractionated using silica gel column chromatography. The fractions obtained in each column were grouped by analysis in thin layer chromatography. On the basis of thin-layer chromatography and antibacterial activity assay, some of the fractions were purified. Of these fractions, the following sterols were identified: 5α-ergost-7-en-3β-ol; 5α-ergost-7,22-dien-3β-ol; 5,8-epidioxi-5α,8α-ergost-6,22-dien-3β-ol; and the triterpenes applanoxidic acids A, C, F, and G. A preliminary study on the antibacterial activity of the extracts and chromatographic fractions obtained was carried out by the agar diffusion method. The extracts and some fractions were active mainly against the Gram-positive bacteria Bacillus cereus and Staphylococcus aureus.