ABSTRACT
The threat posed by diseases such as cancers and infections is everincreasing. Challenges to public health and well-being include the development of drug-resistant microbes and life threatening viruses, and the problems caused by loss of biodiversity and the degradation of natural resources as a result of toxic organic insecticides and industrial effl uent. Therefore, there is a general need for new and useful bioactive compounds, which are highly effective, possess low toxicity and have minor environmental impact. Traditionally, such compounds (commonly referred to as “natural products”) have come from the natural environment, such as microorganisms, plants and invertebrates. However, a recent trend has been to screen libraries of synthetic chemicals for bioactivity. Although this approach has brought some success, the general consensus is that outcomes have been generally disappointing. Therefore, interest is once again turning to natural products for the discovery of new drugs and chemical compounds. Without doubt, natural products have been the single most productive source for the development of new drugs, 1Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, PO Box 218, Hawthorn VIC 3122, Australia. aE-mail: bzaferanloo@swin.edu.au bE-mail: pmahon@swin.edu.au cE-mail: epalombo@swin.edu.au *Corresponding author
particularly anti-cancer and anti-infective agents. While plants have been a great source of valuable bioactive compounds, attention has recently turned to endophytes-microorganisms (fungi and bacteria) living in the intercellular spaces of plant tissues without causing any obvious harmwhich are recognized as potential sources of novel secondary metabolites with potential application in medicine, agriculture and industry (Bacon and White 2000). It is noteworthy that each of the approximately 300,000 plant species which exist on our planet is host to one or more endophytes (Strobel and Daisy 2003). In addition, it is estimated that there may be as many as one million different fungal species, of which only a handful have been studied in detail (Ganley et al. 2004). Endophytes synthesize an enormous range of bioactive compounds (Owen and Hundley 2004), thus there is a great opportunity to fi nd new natural products from interesting endophytic microorganisms among the myriad of plants in different niches and ecosystems.
