Flavone and isoflavone derivatives of terrestrial plants as larval settlement inhibitors of the barnacleBalanus amphitrite

Abstract

To determine whether they could serve as non-toxic or less damaging alternative antifouling (AF) agents, 17 flavone and isoflavone derivatives were isolated from terrestrial plant extracts, purified and examined for their ability to inhibit the settlement of barnacle (Balanus amphitrite) cyprids. In larval bioassays, eight compounds showed strong anti-larval settlement activities, with EC(50) values <10 microg ml(-1). Through an analysis of the structure-activity relationship of these compounds, it was found that (1) the structural difference between flavones and isoflavones did not affect their AF activities; (2) the 5-hydroxyl group on the skeletons played a key role in AF activities; and (3) the presence of hydroxyl group or bulky group on C3 significantly reduced AF activities. A hydrolysis experiment using genistein, a typical active compound in this study, indicated that it was decomposed in the marine environment by hydrolysis reaction and that the degradation speed was significantly affected by pH. In a field AF test, genistein inhibited the attachment of B. amphitrite on panels coated with genistein-paint mixtures.

Reversible anti-settlement activity againstAmphibalanus(=Balanus)amphitrite, Bugula neritina, andHydroides elegansby a nontoxic pharmaceutical compound, mizolastine

“…About 15 larvae from the same batch were added to each well with four replicated samples being tested. To calculate metamorphosis rates, the numbers of settled juveniles and dead or moving larvae in each well were counted under a dissecting microscope after they had been incubated in the dark for 24 h at 248C (Kawahara et al 1999;Dahms et al 2004;Zhou et al 2009). The control wells contained 1 ml of FSW.…”

“…In response to the urgent demand for environmentally friendly antifoulants, some scientists have switched their focus to commercially available chemicals (Rittschof et al 2003;Leroy et al 2008;Zhou et al 2009), including some pharmaceutical compounds that have been proposed to be potentially useful antifoulants (Rittschof et al 2003). For instance, studies on medetomidine, a sedative that relieves pain and relaxes muscles, have revealed its potential application in nontoxic AF paint development (Bellas et al 2006;Hilvarsson et al 2007).…”

Coumarins from the Herb Cnidium monnieri and Chemically Modified Derivatives as Antifoulants against Balanus albicostatus and Bugula neritina Larvae

“…So far, most of the AF natural products have been obtained from marine organisms [9,11–19], but some natural products, which were found in herbal plants, have also proved to be AF agents [20,21]. Compared with marine organisms, many species of herbal plants are easily obtained on an industrial scale because of the rapid development of the herbal industry [22].…”

Flavonoids from the halophyteApocynum venetumand their antifouling activities against marine biofilm-derived bacteria

“…In previous investigations, 8-Omethylretusin had been reported to be isolated from several plants such as Wistaria brachybotrys (Konoshima et al 1997), Dipteryx alata (Puebla et al 2010), Sophora tonkinensis ) and so on. Some researches also suggested that it had exhibited antitumour-promoting (Konoshima et al 1997) and antifouling activities (Zhou et al 2009). …”