9, 4.9, and 2.5 μM, respectively, showing significantly higher effects than the positive control genistein (IC50 9.8 μM). Compound 160 showed a weaker inhibitory Lazertinib effect with an IC50 value of only 24.5 μM. In contrast, 165 and the known 6′-O-desmethylcandidusin B (167), featuring a furan ring in their structures, showed inhibitory activity in an acetylcholinesterase assay with IC50 values of 7.8 and 5.2 μM, respectively. The remaining compounds (161 and 162) showed no inhibition of both enzymes (IC50 > 100 μM) (Huang et al. 2011). Three new 14-membered resorcylic acid lactones, two bearing a rare natural acetonide group, cochliomycins A and B (168 and 169), and one compound with a 5-chloro-substituted

lactone, cochliomycin C (170), together with four known analogues, NCT-501 chemical structure were isolated from cultures of Cochliobolus lunatus, a fungus obtained from the gorgonian selleck compound Dichotella gemmacea (Ellisellidae) collected from the Weizhou coral reef in the South China Sea. The isolated resorcylic acid lactones were evaluated for their antifouling activity against the barnacle Balanus amphitrite. Cochliomycin A (168) and the known zeaenol (171), LL-Z1640-1 (172), and paecilomycin F (173) completely

inhibited larval settlement of B. amphitrite at a concentration of 20.0 μg/mL. Cochliomycin A (168) showed a significant inhibitory activity even at a concentration of 5.0 μg/mL (12.4 μM), but it was also toxic to the larvae at this concentration. Furthermore, 168 and 171–173 showed potent antifouling Adenosine activities at nontoxic concentrations with IC50 values of 3.0, 13.7, 14.6 and 48.9 μM, respectively. These values were lower than the standard requirement of an IC50 of 25 μg/mL established by the U.S. Navy program as an efficacy level for natural antifouling agents and indicated for the first time antifouling activities for this class

of metabolites (Shao et al. 2011b). A culture of a marine-derived Aspergillus sp. yielded two novel benzylazaphilone derivatives having an unprecedented carbon skeleton, aspergilone A (174) and its symmetrical dimer with a unique methylene bridge, aspergilone B (175). The fungus was isolated from the gorgonian D. gemmacea collected from the South China Sea. Aspergilone A (174) exhibited strong inhibition of larval settlement of B. amphitrite at nontoxic concentration with an IC50 value of 19.9 μM. The compound also showed selective in vitro cytotoxicity toward the human cancer cell lines HL-60 (promyelocytic leukemia), MCF-7 (breast adenocarcinoma) and A-549 (lung carcinoma) with IC50 values of 8.3, 64.8 and 95.9 μM, respectively. Aspergilone B (175), however, was inactive in the cytotoxicity assays, indicating the importance of the monomeric form for the observed activity (Shao et al. 2011a,b). The marine-derived fungus Stachylidium sp.