http://www.eurekalert.org/pub_releases/2007-01/aps-aii011807.php

Publicreleasedate:18-Jan-2007

ActiveingredientincommonChineseherb
(Bethesda,MD)--Some50millionAmericanshavehypertension,thatis,bloodpressuremeasuringabovethenormalrange(lessthan120/80mmHg).Ifuntreated,itcanleadtoheartattacks,strokes,orkidneydisease.Lifestylechangesarethefirst-stagetreatmentforthedisease,butiftheyfail,medicationsareprescribed.

Manypatientswithhighbloodpressurehavesoughtrelieffromcomplementaryandalternativemedicine(CAM).Insodoing,manyhaveconsumeddanshen,aChineseherbusedinOrientalmedicinethatpromotesbloodflowandtreatscardiovasculardisease.

TanshinoneIIAisanactiveingredientofdanshen.SincetanshinoneIIAiswidelyavailable,ateamofresearchershasusedittoinvestigateifthisactiveingredientcanreducebloodpressure.Inasoon-to-be-releasedstudy,usingananimalmodel,thescientistshavefoundthattanshinoneIIAdoesreducebloodpressure.

SummaryofMethodology

ToassesstheeffectoftanshinoneIIA,theprotocolconsistedofseveralparts.Theresearchersappliedthe2-kidney-1-clipprotocoltoinducerenalhypertensioninmalegoldenSyrianhamsters.Theanimalswereanesthetizedandaretroperitonealapproachwasusedtoplaceasilvercliptoconstricttherightrenalartery.Sham-operatedhamstersandmiceunderwentthesameprocedure,exceptfortheplacementofaclip.

Bothsetsofhamstersreceived50μgoftanshinoneIIA/100gofbodyweightonceadayfortwoweeks.Afterthetwo-weektreatmentperiod,meanarterialbloodpressurewasmeasuredintherightcarotidartery.ToexaminethemicrovascularactionsoftanshinoneIIAresearchersappliedittopicallytothehamsters’cheekpouchormicecremastermusclestoachievethefinalconcentrationofoneμg/mlorfiveμg/ml.AftertheapplicationoftanshinoneIIA,theexperimentwascontinuedforanadditional60-minuteperiodinordertomeasurearteriolardiameterandperi-arteriolarnitricoxideconcentration.

Results

TanshinoneIIAwasfoundtohavesignificantlyreducedbloodpressureinthehamsters.Theexperimentalconstrictionoftherenalarteryincreasedmeanarterialpressureto161.2±6.9mmHgrelativeto114.3±9.2mmHginage-matchedhamsters.Treatmentwith50μgtanshinoneIIA/100gbodyfortwoweeksreducedthemeanarterialpressurefrom161.2±6.9to130.0±7.8mmHg.

TheresearchteamalsodiscoveredthattanshinoneIIAcausedwideningofthearteriolesinthehamstercheekpouchmicrocirculationviaenhancedexpressionofendothelialnitricoxidesynthase.ThetopicalapplicationoftanshinoneIIAatoneμg/mlandfiveμg/mlcausedsignificantdose-relatedvasodilation,indicatedbytheincreasedagent/controlratioofarteriolardiametersfrom1.0to1.25±0.08and1.57±0.11,respectively,inthehamstercheekpouch.TheincreaseinarteriolardiameterratiowassignificantrelativetothevehicleforeachconcentrationaswellasforcomparisonbetweenthetwoconcentrationsoftanshinoneIIA.

Conclusions

AsaresultofthefindingstheresearchersconcludedthattanshinoneIIA:(1)significantlyreducedbloodpressureinhamsters,(2)enhancedtheexpressionofendothelialnitricoxidesynthase,(3)increasedtheproductionofnitricoxideand(4)inducedbloodpressurechangesthroughvasodilationinhamsterbloodmicrovessels.WhilethemechanismsofhowtanshinoneIIAordanshenworkinhypertensionarenotyetfullyunderstood,theseresultscontributetotheefforttobringcomplementaryandalternativemedicineandallopathiccareclosertogetherinthetreatmentofhypertensivepatients.