African Journal of Microbiology Research Vol. 7(3), pp. 202-210, 15 January, 2013 Available online at http://www.academicjournals.org/AJMR DOI: 10.5897/AJMR12.1774 ISSN 1996-0808 ©2013 Academic Journals Full Length Research Paper DNA-binding activity and in vivo cytotoxicity of Ganoderma applanatum (Pers.) Pat. supercritical-CO 2 extracts Zeus S. Elumba 1 , Franco G. Teves 2 * and Roberto M. Malaluan 3 1 Department of Biology, Central Mindanao University, Musuan, Bukidnon, Philippines. 2 Department of Biological Sciences, Mindanao State University-Iligan Institute of Technology, Iligan City, Philippines. 3 Department of Chemical Engineering Technology, Mindanao State University-Iligan Institute of Technology, Iligan City, Philippines. Accepted 11 October, 2012 Ganoderma applanatum (Pers.) Pat. is a perennial and abundant mushroom in Bukidnon Province, Philippines but its bioactivities have just been investigated lately. In this study, three supercritical-CO 2 (SC-CO 2 ) extracts (GA1, GA2 and GA3) from the local strain of G. applanatum (Pers.) Pat. were examined for their DNA-binding potential by means of biomolecular-chemical screening and in vivo cytotoxicity using brine shrimp lethality assay (BSLA). All extracts contained secondary metabolites that have DNA- binding activity towards salmon sperm DNA (Rf 2 /Rf 1 -ratio <1). For BSLA, the LC 50 (24 h) values ranged from 177.82 to 354.81 μg/ml, indicating that the extracts are biologically active but with no significant cytotoxicity. Reverse-phase HPLC and FT-IR spectroscopy were carried out to partially characterize the extracts. Results of this study showed that G. applanatum (Pers.) Pat. from Bukidnon Province, Philippines is a potential source of biologically active, non-toxic compounds with DNA-binding activity. Key words: Ganoderma applanatum, DNA-binding activity, cytotoxicity, supercritical-CO 2 . INTRODUCTION Mushrooms have been valued for generations as source of medicines or as food. For centuries, the medicinal use of mushrooms such as Ganoderma was recorded in China, Japan and Korea (Paterson, 2001). Of the approximately 10,000 known species of mushrooms, 2000 are safe for human health and about 300 of them possess medicinal properties (Wasser and Weis, 1999). Mushrooms can synthesize a dazzling array of biologically-active products which have no significant role in their primary physiological processes (Kidukuli et al., 2010). These are secondary metabolites that have often attracted interest because of their biological effect on other organisms. The strong activities of these bioactive compounds enable mushrooms to survive in their *Corresponding author. E-mail: franco_teves@yahoo.com. Tel/Fax: (+63) 063 223 2343. environments and allow them to out-compete their environmental competitors (Kidukuli et al., 2010). It is not surprising therefore that mushrooms contain secondary metabolites that may have economic and pharmaceutical values. Ganoderma is a prolific producer of novel “mycochemicals” (Paterson, 2006). There are reports on its folkloric use for the treatment of various ailments (Rowan et al., 2002; Jeong et al., 2008). Phytochemical studies of Ganoderma applanatum (Pers.) Pat. showed that it contains triterpenoids, tannins, sterols, steroids, proteins and polysaccharides (Boh et al., 2000; de Silva et al., 2006; Chairul et al., 1991; Strigina et al., 1971). Previous studies demonstrated its antioxidant, antimicrobial, immunomodulating, aldose reductase inhibitors, nitric oxide synthase activators and anti-tumor properties (Barranco et al., 2010; Muhsin et al., 2011; Smania et al., 1999; Lee et al., 2005; Acharya et al., 2005; Jeong et al., 2008; Chairul et al., 1991). However,