title: Nontoxic piperamides and their synthetic analogues as novel antifouling reagents.
abstract: Bioassay-guided isolation of an acetone extract from a terrestrial plant Piper betle produced four known piperamides with potent antifouling (AF) activities, as evidenced by inhibition of settlement of barnacle cypris larvae. The AF activities of the four piperamides and 15 synthesized analogues were compared and their structure-activity relationships were probed. Among the compounds, piperoleine B and 1-[1-oxo-7-(3',4'-methylenedioxyphenyl)-6E-heptenyl]-piperidine (MPHP) showed strong activity against settlement of cyprids of the barnacle Balanus amphitrite, having EC50 values of 1.1 ± 0.3 and 0.5 ± 0.2 μg ml(-1), respectively. No toxicity against zebra fish was observed following incubation with these two compounds. Besides being non-toxic, 91% of piperoleine B-treated cyprids and 84% of MPHP-treated cyprids at a concentration of 100 μM completed normal metamorphosis in recovery bioassays, indicating that the anti-settlement effect of these two compounds was reversible. Hydrolysis and photolysis experiments indicated that MPHP could be decomposed in the marine environment. It is concluded that piperamides are promising compounds for use in marine AF coatings.
authors.affiliation: a Division of Life Science , The Hong Kong University of Science and Technology , Hong Kong SAR , China.
authors.forename: Xiang-Zhong
authors.initials: XZ
authors.lastname: Huang
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yue Him
authors.initials: YH
authors.lastname: Wong
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Han
authors.forename: Yan
authors.initials: Y
authors.lastname: Yin
authors.forename: Pei-Yuan
authors.initials: PY
authors.lastname: Qian
mesh_terms: D000577:Amides / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D057219:Biofouling; D006868:Hydrolysis; D007814:Larva / Q000187:drug effects; D010782:Photolysis; D031721:Piper betle / Q000737:chemistry*; D017166:Toxocara canis / Q000187:drug effects; D015027:Zebrafish / Q000196:embryology
chemical_list: D000577:Amides