91BiotechnologicalpotentialofNorthSeasaltmarshplan

JournalofBiotechnology70(1999)77–84BiotechnologicalpotentialofNorthSeasaltmarshplants—areviewoftraditionalknowledgeGerdLiebezeita,*,ThorstenD.Ku¨nnemannb,GunnarGadbaForschungszentrumTerramare,Schleusenstraße1,D-26382Wilhelmsha6en,GermanybFBBiologie,Uni6ersita¨tOldenburg,Postfach2503,D-26111Oldenburg,GermanyReceived13October1998;receivedinrevisedform1December1998;accepted22December1998AbstractExtremeenvironmentsarecharacterisedbywidevariationsinphysicalfactors.TidalflatsandtheiradjacentsaltmarshesalongtheNorthSeacoastexperiencethistypeofvariabilityonadaily,seasonalandannualbasis.Plantsandanimalslivingintheseextremeenvironmentshavetoadapttothese,attimesrapid,changes.Thiscanbedonebydevelopingspecificphysiologicalresponseswhichoftenencompassthesynthesisofunusualchemicals.Anumberofsaltmarshplantshavetraditionallybeenusedformedical,nutritionalorevenindustrialpurposes.Here,examplesarepresentedfortheseplants.©1999ElsevierScienceB.V.Allrightsreserved.Keywords:Extremeenvironments;Saltmarshplants;Semiterrestrial1.IntroductionOrganismsthrivinginextremehabitatshavedevelopedanumberofmechanismstocopewiththeirphysicalenvironment.Thesemayincludea.o.theproductionofantifreezecompoundsorheatshockproteinsinfishandotherorganisms(SicherlandYang,1995;Bergeretal.,1996),specificenzymesystemscapableofoperatingattemperaturesashighas113°C(Blo¨chletal.,1997)oratdeepseapressures(Huberetal.,1989;GrossandJaenicke,1994).Therefore,consider-ablebiotechnologicalinterestintheseenviron-mentshasrecentlybeenexpressed(Jensen,1993;Pennisi,1997;Gross,1998).Extremeenvironmentsareusuallydefinedasbeingextremeinoneorseveralphysicalparame-terssuchastemperature(e.g.hydrothermalvents,ice-coveredregions),salinity(hypersalinelagoons,DeadSea)orpressure(deepsea).However,inthesesystemstheexternalvariablesremainrela-tivelystableovertimeandareextremeonlybyhumanstandards.Ontheotherhand,marinesystemswithahighvariabilityintemperature,salinityorradiationcanalsobefound.Theseincludea.o.saltmarshes,tidalflatsandmangroveecosystems.Organismsthrivinginsalineenvironmentshavebeenfoundtoproducealargenumberofsec-*Correspondingauthor.E-mailaddress:[e-mail](G.Liebezeit)0168-1656:99:$-seefrontmatter©1999ElsevierScienceB.V.Allrightsreserved.PII:S0168-1656(99)00061-9G.Liebezeitetal.:JournalofBiotechnology70(1999)77–8478ondarynaturalproductsthatmightbeofpoten-tialinterestforpharmacologicalorindustrialap-plications(Hay,1996).Marineneurotoxins,forexample,maybeusedtostudyionchannelsandreceptors(Myersetal.1993).Bryostatins,isolatedfrombryozooans,arecurrentlybeinginvestigatedaspowerfulanti-leukemiaagents(Olson,1996).Saltmarshesandtidalflatsexperienceregular(e.g.tides)andirregular(e.g.storms)externalinfluences.Temperaturesmayvaryfrombelow20°Cinseverewintersto\40°Cinextremesummers,whilethesaltregimemaychangefromfreshwaterconditionsafterheavyrainstohyper-salineafterprolongedevaporationperiods(Rei-neckandFlemming,1990).Tobeabletodealwiththesevariationsinenvironmentalconditionsorganismsinhabitingtheseecosystemshavedevel-opedanumberofadaptationmechanisms.Theseincludemechanismsfora.o.saltexcretionorstor-age,osmoregulation(i.e.controlofcellularionconcentrations)ordesiccationprotection.Inthiscontextitshouldbementionedthatoutof16mangrovespeciestestedforantiviralactivity,10werefoundtocontainactivecompounds(PadamakumarandAyyakkannu,1994),whileofthemarinemacroalgaeinvestigatedonly30%be-havedsimilarly.Thedocumentedproductionofsaponinsinseeds(Glennetal.,1991)orothertoxiccompoundsbysaltmarshplants(Cooper,1984)canberegardedasamechanismtoavoidoratleasttominimisepredationpressure.Thissug-geststhatsemiterrestrialplantsmaybeaparticu-larlywealthysourceforunusualchemicalcompounds.Marinebiotechnologylargelydependsontheavailabilityofinformationonthenaturalprod-uctschemistryofmarineorganisms(Rouhi,1995;Colwell,1983)whichcanbeobtainedinvariousways.Oneoftheseistheinstallationofscreeningprogrammes,wherebyorganismsofinterestaresystematicallyinvestigatedforusuallyarestrictednumberofbiologicalactivities.Thelattermayencompassantibacterial,antiviralorothercom-poundsofpharmacologicalinterest.Asecondap-proachistousetraditionalknowledgeasassembledine.g.homeopathytextbooksorpassedonbyfolklore.Inthesecases,generallynodetailsonthestructuresofmoleculesofinterestwillbemadeavailableiftheyareknownatall.Rather,thesesourcescanbeusedtoobtaininfor-mationonthebiologicalactivitiesdisplayedbydifferentplantsorpartsthereof.Inthisreviewwewillconcentrateonthissec-ondapproach,takingacloserlookatselectedplantsfromNorthSeasaltmarshes,chieflyglass-wort(Salicorniaspp.),sealavender(Limonium6ulgare),arrowgrass(Triglochinmaritima),seawormwood(Artemisiamaritima)andseaplantain(Plantagomaritima).Otherplantswhichhavealsobeenusedtraditionallywillbementionedbriefly.2.MethodsTheinformationprovidedhereisbasedonanintenseliteraturesearchincludingWorldWideWebsources,notably(1909,1926).Fur-thermore,forinformationonhomeopathicusageofplantsthepublicationsofAnton(nopub