Marine-derived bacteria and fungi are promising sources of novel bioactive compounds that are important for drug discovery programs. However, as encountered in terrestrial microorganisms there is a high rate of redundancy that results in the frequent re-discovery of known compounds. Apparently only a part of the biosynthetic genes that are harbored by fungi and bacteria are transcribed under routine laboratory conditions which involve cultivation of axenic microbial strains. Many biosynthetic genes remain silent and are not expressed in vitro thereby seriously limiting the chemical diversity of microbial compounds that can be obtained through fermentation. In contrast to this, co-cultivation (also called mixed fermentation) of two or more different microorganisms tries to mimic the ecological situation where microorganisms always co-exist within complex microbial communities. The competition or antagonism experienced during co-cultivation is shown to lead to a significantly enhanced production of constitutively present compounds and/or to an accumulation of cryptic compounds that are not detected in axenic cultures of the producing strain. This review highlights the power of co-cultivation for increasing the chemical diversity of bacteria and fungi drawing on published studies from the marine and from the terrestrial habitat alike.

For the past 50 years, fungal secondary metabolites have revolutionized medicine yielding blockbuster drugs and drug leads of enormous therapeutic and agricultural potential. Since the discovery of penicillin, the first β-lactam antibiotic, fungi provided modern medicine with important antibiotics for curing life threatening infectious diseases. A new era in immunopharmacology and organ transplantation began with the discovery of cyclosporine. Other important drugs or products for agriculture derived from or inspired by natural products from fungi include statins, echinocandins and strobilurins. Moreover, fungal biotransformation of steroids for the industrial production of steroidal hormones represents one of the key successes in biotechnology. Given that estimations of fungal biodiversity exceed by far the number of already identified species, chances to find hitherto unidentified fungal species and novel bioactive fungal products are still high. Thus, further compounds with medicinal or agricultural potential from less investigated fungal taxa can be expected in the years to come.

The potential of mangrove-derived endophytic fungi as a promising source of diverse and structurally unprecedented bioactive natural products is unquestionable and continues to attract considerable attention. This review highlights new bioactive mangrove fungal metabolites and known compounds with hitherto unreported biological activities described during the last 10 years. The compounds are categorized according to their reported biological activities, including cytotoxic, anti-infective, in addition to a wide range of miscellaneous activities such as protein kinase, α-glucosidase, acetylcholinesterase and tyrosinase inhibitory activities, as well as antiangiogenic and neovascularisation effects, radical scavenging, DNA-binding affinity, and calcium and potassium channel blocking activity.

The potential of endophytes and algal or invertebrate associated marine derived fungi as promising sources of structurally unprecedented bioactive natural products is undeniable and continues to attract broad attention. This review highlights new bioactive fungal metabolites reported in 2011 until April 2012, as well as known compounds for which novel biological activities have been disclosed. All compounds are grouped according to their reported biological activities which include cytotoxic, anti-infective, as well as radical scavenging, enzyme inhibition, anti-fouling and anti-parasitic activities. Overall, 178 fungal metabolites, including 138 new natural products are presented. Furthermore, new insights into fungal-host interaction, chemical communication, and chemo-ecological roles of fungal metabolites, as well as new strategies for bioprospecting are presented.