Botanica Marina 54 (2011): 95–100  2011 by Walter de Gruyter • Berlin • New York. DOI 10.1515/BOT.2011.005 2010/114 Article in press - uncorrected proof Cytotoxic and antimicrobial activities of Malaysian marine endophytic fungi Siti A. Ariffin 1,2, *, Paul Davis 1 and Kalavathy Ramasamy 2 1 Department of Medicine, University of Otago, PO Box 7343, Newtown, Wellington South 6242, New Zealand, e-mail: adeqteq_teq@yahoo.com 2 Collaborative Drug Discovery Research (CCDR) Group, Faculty of Pharmacy, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor Darul Ehsan, Malaysia * Corresponding author Abstract Endophytes from marine plants have not been widely explored, and their bioactive compounds are not well-docu- mented. In the present study, 64 endophytic fungi were iso- lated from Malaysian marine plants and seaweeds. The endophyte extracts were tested for cytotoxic (seven cancer cell lines) and antimicrobial (against four bacteria and two fungi) activities. Out of 64 extracts tested, 49 (77%) were able to inhibit cancer cell lines. Eight of the endophyte extracts that were potent (IC 50 F0.1 mg ml -1 ) against colon and lung cancer cell lines were further compared for their effects on a normal human fibroblast cell line. The marine endophytic fungal extracts showed stronger antimicrobial activity against bacteria (72%) than fungi (16%). The bio- activity of a few selected marine endophytic fungal extracts was comparable to a number of current commercial antican- cer, antibacterial and antifungal agents. Results from the present study indicate marine endophytic fungi are a prom- ising source for anticancer and antimicrobial agents. Keywords: anticancer; antimicrobial; cytotoxic; endophytes; seaweed. Introduction The marine ecosystem is a rich and prolific source of poten- tially bioactive compounds that might be associated with pharmaceutical products. Large numbers of marine plants (Bhosale et al. 2002, Laurent and Pietra 2006) and marine fungi (Bhadury et al. 2006, Jones et al. 2008, Mayer and Gustafson 2008, Pan et al. 2008) have antibacterial, antifun- gal, analgesic, anti-inflammatory, antitumor and antihyper- tensive activities. However, endophytes have not been fully explored but are expected to be an important source for new natural bioactive agents (Zheng et al. 2005, Newman and Hill 2006). Endophytes are microorganisms that colonize liv- ing material and tissue of plants without causing harm (Stro- bel 2006). About 51% of biologically active substances isolated from endophytic organisms were reported to be new (Strobel 2003, Strobel and Daisy 2003). Endophytes have been studied predominantly for their potential as antimicrobial and antitumour agents (Jones et al. 2008, Mayer and Gustafson 2008, Pan et al. 2008) but marine endophytic fungi have not been adequately explored in this area (Raghukumar 2008). Through 2005–2006, lep- tosins C and F (Yanagihara et al. 2005) and verrucarin A (Oda et al. 2005) were the only compounds from marine endophytic fungi to have their mechanisms of action against lymphoblastoid (RPMI18402) and promyelocytic leukemia (HL-60) cells, respectively, established, while numerous compounds remained undetermined. Furthermore, endo- phytes from marine algae were reported to be poorly docu- mented when compared with those from mangrove plants (Jones et al. 2008). In the present study, endophytic fungi were isolated from two marine trees w Pandanus amaryllifolius Roxb. (monocot- yledonous coastal tree) and Nypa fruticans Wurmb (man- grove palm growing in estuarine mud)x and six types of seaweeds collected from Port Dickson, Negeri Sembilan, Malaysia (Table 1). These marine angiosperms and seaweeds have been used widely by indigenous people, and each part of these organisms has unique properties for the treatment of various types of ailments (Bandaranayake 2002, Radu and Kqueen 2002, Newman and Hill 2006). Sixty-four marine endophytic fungi that were isolated from the trees and sea- weeds were tested for antimicrobial activity and cytotoxic activity against seven cancer cell lines. Materials and methods Isolation of endophytes Endophytes were isolated from Pandanus amaryllifolius, Nypa fruticans and brown and green seaweeds from Teluk Kemang Port Dickson, Negeri Sembilan, Malaysia, as described by Strobel (2003). Different parts of the trees (fruits, stem, roots and leaves) or seaweeds were washed under running water, sterilized with 75% EtOH for 1 min and household bleach (5% NaOCl) for 3 min, drained and immersed in 75% EtOH again for 30 s. Finally, the samples were rinsed with sterile water and cut aseptically into 1 cm long segments. The cut segments were incubated on potato dextrose agar (PDA, Oxoid, Basingstoke, UK) supplemented with chloramphenicol (10 g l -1 Sigma-Aldrich, St Louis, MO, USA) at 288C until mycelia were observed. Pure cultures Brought to you by | University of Arizona Library Authenticated | 150.135.135.70 Download Date | 12/21/12 2:13 AM