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Herbal plants as a promising source of natural antifoulants: evidence from barnacle settlement inhibition

Authors Feng, D. Q.; Ke, C. H.; Lu, C. Y.; Li, S. J.

Journal BIOFOULING , 2009,3:25

DOI 10.1080/08927010802669210 PubMed 19169950

Abstract A series comprising hexane, ethyl acetate, ethanol and aqueous extracts from six common Chinese herbs (Carpesium abrotanoides, Melia toosendan, Cnidium monnieri, Vitex negundo, Stemona sp. and Sophora flavescens) was investigated for antifouling (AF) activity against cypris (cyprids) larvae of the barnacle Balanus albicostatus. All extracts tested except the aqueous extract from Stemona sp. significantly inhibited the settlement of cyprids, the most potent being the ethyl acetate extract of S. flavescens (EC50 value 2.08 mu g ml(-1)), from which an AF compound, identified as 2''-methoxykurarinone, was isolated using bioassay-guided procedures. Furthermore, the AF activity of this compound was found to be highly reversible and greater than that of the three other natural products from S. flavescens, namely matrine, oxymatrine and oxysophocarpine. These compounds have been used commercially in China for their pharmaceutical activities, but their AF activities have not previously been evaluated. Analysis of structure-activity relationships suggested that the N-1 nitrogen atom in matrine plays a crucial role in AF activity. Overall, the present findings indicate that herbal plants are a valuable source of novel AF agents.

Species covered 苦参 Sophora flavescens 天名精 Carpesium abrotanoides 蛇床 Cnidium monnieri 川楝 Melia toosendan