Thielavins W-Z₇, New Antifouling Thielavins from the Marine-Derived Fungus Thielavia sp. UST030930-004.

Eleven new depsides-thielavins W-Z ( 1 - 4 ) and thielavins Z₁-Z₇ ( 5 - 11 )-and also four known thielavins-A, H, J, and K ( 12 - 15 )-were isolated from the ethyl acetate extract of a marine-derived fungal strain Thielavia sp UST030930-004. All of these compounds were evaluated for antifouling activity against cyprids of the barnacle Balanus (= Amphibalanus ) amphitrite . The results showed that compounds 1-3 and 6-13 were active, with EC50 values ranging from 2.95 ± 0.59 to 69.19 ± 9.51 μM, respectively. The inhibitive effect of compounds 1 - 3 and 7 was reversible. This is the first description of the antifouling activity of thielavins against barnacle cyprids.