Three new bianthraquinone derivatives, alterporriol K (1), L (2) and M (3), along with six known compounds were obtained from extracts of the endophytic fungus Alternaria sp. ZJ9-6B, isolated from the mangrove Aegiceras corniculatum collected in the South China Sea. Their structures were elucidated by one- and two-dimensional NMR spectroscopy, MS data analysis and circular dichroism measurements. Compounds 1, 2 and 3 were first isolated alterporriols with a C-2–C-2′ linkage. The crystallographic data of tetrahydroaltersolanol B (7) was reported for the first time. In the primary bioassays, alterporriol K and L exhibited moderate cytotoxic activity towards MDA-MB-435 and MCF-7 cells with IC50 values ranging from 13.1 to 29.1 μM.

A new alternariol derivative, 2240B (1), together with alternariol (2), alternariol 4, 10-dimethyl ether (3), and alternariol 4-methyl ether (4), was isolated from the ethyl acetate extract of the liquid medium GYT of No. 2240, the mangrove endophytic fungus from the South China Sea Coast. The structure of compound 1 was unambiguously elucidated as alternariol 4-methyl-10-acethyl ester by spectra including one/twodimensional NMR, HREIMS, IR, and UV. The structures of compounds 2-4 were also established by spectroscopic analyses and comparison with related literature data. The anticancer tests showed that compounds 2 and 4 had strong activities against KB and KBv200 cells with IC 50 values of 3.17, 3.12, and 4.82, 4.94 μg/mL, while compounds 1 and 3 exhibited weak activities against the two kinds of tumor lines with IC 50 values of more than 50 μg/mL. Key words: alternariol derivatives, mangrove endophytic fungus, alternariol 4-methyl-10-acethyl ester, mutagenicity, KB tumor lines, KBv200. 1: R 1 = OMe, R 2 = Ac; 2: R 1 = R 2 = OH 3: R 1 = R 2 = OMe; 4: R 1 = OMe, R 2 = OH

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A diverse array of bioactive metabolites have been isolated and characterized from fungi isolated from countries surrounding the South China Sea. From extensive studies of marine fungi of the South China Sea, 25 fungal strains (comprising endophytes, obligate and marine-derived fungi) were screened for bioactive compounds. This resulted in the reporting of 42 new or novel compounds and 35 known compounds (data from 1999–2007). Their biological activities, structural and stereochemical assignments and syntheses of some structurally unique natural products are reported.

This review describes the present hot research areas of mangrove-associated fungi, including its biodiversity, ecological roles, novel metabolites productions and biotechnological potential. Mangrove-associated fungi were divided into saprophytic, parasitic and true symbiotic fungi based on its ecological roles. Saprophytic fungi are fundamental to decomposition and energy flow of mangrove, additionally, their potential toxicity also exists. Pathogenic fungi have significant effects on mangrove survival, growth, and fitness. Endophytic fungi, the most prolific source of diverse bioactive compounds found among that of mangrove-associated fungi, are found in most species of mangroves. Although a significant number of reports focused on the antimicrobial, insecticidal and other bioactive metabolites as well as many novel enzymes isolated from mangrove-associated fungi, and many of those metabolites from endophytic fungi are suspected to be of significant to mangrove, only few studies have provided convincing evidence for symbiotic producers in mangrove. Hence, this paper discusses the present progress of molecular methods used to correlate the ecological roles of endophytic fungi with their bioactive metabolites; , meanwhile, the potential of using metabolic engineering and post-genomic approaches to isolate more novel enzymes and bioactive compounds and to make their possible commercial application was also discussed.