Rev. bras. farmacogn. vol.25 número3

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w w w. s b f g n o s i a . o r g . b r / r e v i s t a

Original

Article

Hypoglycemic

and

hypolipidemic

effects

of

Solidago

chilensis

in

rats

Mariane

Schneider

a

_,

_Adrieli

_Sachett

a

_,

_Amanda

_P.

_Schönell

a

_,

_Eduarda

_Ibagy

a

_,

_Emily

_Fantin

a

_,

Fernanda

Bevilaqua

a

_,

_Giana

_Piccinin

a

_,

_Glaucia

_D.

_Santo

a

_,

_Marta

_Giachini

a

_,

_Rafael

_Chitolina

a

_,

Silvana

M. Wildner

a

_,

_Ricieri

_Mocelin

b

_,

_Leila

_Zanatta

b

_,

_Walter

_A.

_Roman

_Junior

c,∗

a_Núcleo_de_{Fitoterápicos,}_Universidade_Comunitária_da_Região_de_Chapecó,_Chapecó,_SC,_Brazil

b_Programa_de_{Pós-graduac¸}_ão_em_Ciências_Ambientais,_Universidade_Comunitária_da_Região_de_Chapecó,_Chapecó,_SC,_Brazil

c_Programa_de_{Pós-graduac¸}_ão_em_Ciências_da_Saúde,_Universidade_Comunitária_da_Região_de_Chapecó,_Chapecó,_SC,_Brazil

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received18December2014 Accepted16May2015 Availableonline10June2015

Keywords:

Antihyperlipidemicactivity Arnica-do-brasil Asteraceae Hypoglycemic

a

b

s

t

r

a

c

t

SolidagochilensisMeyen,Asteraceae,istraditionallyusedtotreatinflammation.However,phytochemical

andpharmacologyinvestigationsarelacking.Thisstudyevaluatedthehypoglycemicandhypolipidemic

effectsofhydroalcoholicextractfromS.chilensisaerialpartsinrats.Inoralglucosetoleranceteststhe

ratsreceivedsaline(0.5ml/100g)incontrolgroup(C),hydroalcoholicextract(125,250or500mg/kg

p.o.;n=6)orglibenclamide(10mg/kgp.o.;n=6).After30min,glucose(4g/kg)wasadministered.Rats

treatedwithhydroalcoholicextract500demonstrateddecreasedglucoselevelsat180min(−22.1%),

whencomparedwithgroupC,similartoglibenclamide.Moreover,treatmentwithhydroalcoholicextract

500significantlyincreasedtheglycogencontentintheliverandsoleusmuscle,andhydroalcoholic

extract250specificallyinhibitedtheenzymemaltasewhencomparedwithgroupC.Furthermore,all

hyperglycemicratstreatedwithhydroalcoholicextract(125,250and500)exhibitedanaccentuated

decreaseintotalcholesterollevels(−36.8%,−36.7%and−41.3%,respectively).Ourresultssuggestthat

hypoglycemicandhypolipidemiceffectsofhydroalcoholicextractcouldbeassociatedwithincreased

productionandreleaseofinsulinaswellaswithinsulinotropicandantioxidanteffects.

Introduction

Diabetesmellitus(DM)comprisesagroupofdisorders involv-ingdistinct pathogenicmechanismswithhyperglycemia asthe commondenominator(Teixeiraetal.,2000).Hyperglycemiain dia-betesmayberelatedtonumerousphysiologicalevents, suchas decreasedglucoseincells,reducedglucoseutilizationbyvarious tissues,and increasedhepaticproduction of glucose (gluconeo-genesis)(Prabhakar et al.,2013).Complicationsexperienced by patientswithdiabetesareoftenrelatedtochronichyperglycemia, includingretinopathy, peripheralvascular disease,renal failure, neuropathy,andcardiovasculardiseasesthatcausebothmorbidity andprematuremortality(Hiranyetal.,2000;Piaulinoetal.,2013). Itiswellestablishedthatpatientswithtype2DMfrequently have abnormal serum lipid profiles comprising elevated low densitylipoproteins(LDL)andtriglycerideslevelsalongwith mod-eratelydecreasedhighdensitylipoproteins(HDL)level(Zimmet, 2000), all of which are associated with an increased risk of

∗ Correspondingauthor.

E-mail:romanwa@unochapeco.edu.br(W.A.RomanJunior).

cardiovasculardiseases(Daietal.,2013).Manystudieshaveshown thatelevatedserumcholesterolconcentrationscancausecoronary atherosclerosis(ParkandVelasquez,2012)thatisassociatedwith heartdisease,stroke,anddeathinbothdevelopedanddeveloping countries(Raidaetal.,2008).

Medicinalplantshavebeenusedformany yearsbydifferent culturesworldwidetotreatDM(Modaketal.,2007).Investigating herbalmedicineshasbecomeprogressivelyimportantinthesearch foranew,effective,andsafetherapeuticagenttocombatDM.More than200purebioactiveprinciplesisolatedfromplantshavebeen showntolowerserumglucoselevels(Groveretal.,2002;Warjeet, 2011),includingphenolicsandflavonoids(Negri,2005).

Solidago chilensis Meyen, Asteraceae, is a species native to the southern region of South America. It is widely distributed in south and southeast Brazil, where it is popularly known as arnica-do-brasil and is used to relieve inflammation (Lorenzi

and Matos, 2002). Its main chemical constituents are

ace-tophenone,carotenes,diterpenoidswithlabdanicandclerodanic skeletons(Soares-Valverdeetal.,2009),flavonoids,glycosides, 3-methoxybenzaldehyde,essential oils, and saponins(Silvaet al., 2010),withquercetrinbeingthemajorconstituent(Torresetal.,

1987).

http://dx.doi.org/10.1016/j.bjp.2015.05.001

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Ethnopharmacologicalinvestigationshave foundthis species tohaveantispasmodic,antihemorrhagic(Alonso,1998), wound-healing(Facury-Netoetal.,2004),andanti-inflammatoryeffects

(Tamura et al., 2009). Recently, there has been considerable

progressintheinvestigationofS.chilensisandgastricprotection

(Bucciarellietal.,2010)aswellasabetterunderstandingofthe

effectofS.chilensisoninsulinresistanceinobesemice(Meloetal., 2011).However,thehypoglycemicandhypolipidemiceffectsofS.

chilensisontheglucosetolerancecurvehavenotyetbeenstudied. Therefore, theobjective ofthis study wastoinvestigatethe hypoglycemicandhypolipidemiceffectsofhydroalcoholicextract (HE) from S. chilensis in rats. This study evaluatedthe glucose tolerance curve along with, liver and soleus muscle glycogen levels,disaccharidaseactivity,totalcholesterol(TC),andalanine aminotransferase(ALT)levels.Moreover,theinvitrofreeradical scavengingpropertiesofS.chilensiswereevaluated.

Materialsandmethods

Plantmaterials

AerialpartsofSolidagochilensisMeyen,Asteraceae,were col-lectedinChapecó,SC,Brazil(S27◦₀₆′_38.83′′_/W₅₂◦₃₄′_26.52′′_)._The

voucherspecimenwasidentifiedbyOsmardosSantosRibasand isdepositedintheherbariumoftheBotanicalMuseumofCuritiba (MBMnumber356792).

Preparationofhydroalcoholicextract

Dried aerial parts of S. chilensis (50g) of the same particle size(300␮m;48Tyler/Mesch)weremaceratedin80%methanol (1000ml)forsixdays.Hydroalcoholicextract(HE)fromS.chilensis

wasconcentratedtodrynessunderreducedpressureat40◦_C_and

thenfreeze-driedandstoredat−20◦_C.

High-performanceliquidchromatographyanalysis

ChromatographyanalysiswasperformedusingaVarian®

Pro-Star HPLC system consisting of an automatic injector, ternary gradientdetectors,pumps,andaUV/VisKromasil®_C18

reversed-phase ODS column (5␮m; 25mm×4.5mm).The mobile phase consistedoftwosolvents:H2O:aceticacid(40:1,v/v;solventA) andCH3CN(solventB)thatwerefilteredthrough0.45␮mMillipore polytetrafluoroethylenemembranes.Separationswereperformed with a linear gradient: 86% solvent A and 14% solvent B for 15min,35%solventBfor20minand100%solventBfor2min.UV absorbanceat360nmwasmeasured,andtheresultswere com-paredwiththeretentiontimesofanauthenticexternalstandard followedbyaUVspectrumanalysis.Theflowrateofthemobile phasewas1ml/min−1_,_and_the_injection_volume_was₂₀_␮_l._The chromatographicrunswereperformedat22◦_C._UV_absorbance_at

360nm wasmeasured(Apátiet al.,2006).Quercetrin (12.5,25, 50,100and200␮g/ml;Sigma–Aldrich®₎_was_analyzed_in

tripli-cate,andacalibrationcurvewasgenerated.HEwasdissolvedin MeOH(1mg/ml)andfilteredthroughamicroporefilter(0.45␮m) beforethechromatographicprofilewasgenerated.Theresultsare expressedastheconcentrationofquercetrin(%)inthedriedplant material.

Invitro2,2-diphenyl-1-picrylhydrazylfreeradicalscavenging assay

ThefreeradicalscavengingactivityofHEwasmeasuredusing themethoddescribedbyBrand-Williamsetal.(1995)withsome modifications.HE(1ml;5–200␮g/ml)wasaddedto2mlofa solu-tionof2,2-diphenyl-1-picrylhydrazyl(DPPH)radicals inethanol

(0.004%).Themixturewasvigorouslyshakenandallowedtostand for30minatroomtemperature(RT).Theabsorbance(Abssample) oftheresultingsolutionwasmeasuredat517nm,andthe antiox-idantactivity(AA)percentagewascalculatedusingthefollowing formula:

AA%=100−(Abssample−Absblank)×100

Abscontrol

Asolutionofethanol(2ml)andHE(1ml)wasusedastheblank (Absblank).AsolutionofDPPH(2ml)andethanol(1ml)wasusedas thecontrol(Abscontrol).Ascorbicandgallicacidswereusedas stan-dards.Freeradicalscavengingactivitywasexpressedintermsof theamountofantioxidantsnecessarytodecreasetheinitialDPPH absorbanceby50%(IC50).TheIC50valuewasdeterminedby inter-polationfromthenonlinearregressionoftheplotofpercentageof inhibitionagainsttheconcentrationofHE,whichisdefinedasthe amountofHEneededtoscavenge50%ofDPPHradicals.

Animals

TheexperimentalprotocolwasapprovedbytheEthics Com-mitteeonAnimalUseoftheCommunityUniversityintheRegion ofChapecó,Brazil(CEUANo.020/2013).Male Rattusnorvegicus, Wistar(n=30)weighing250–275gwereusedinthestudy.The animalswerehousedinwire-bottomed17cm×33.5cm×40.5cm cagesinacontrolledenvironmentat22±2◦_C_with_a₁₂_h_light–dark

cycleandminimalnoise.Theratshadadlibitumaccesstowaterand commerciallypreparedrodentchowpellets(Nuvilab®

CR-1).

Oralglucosetolerancecurve

Animalswerefastedovernightanddividedintogroups con-taining six rats each. The control group (C), received saline (0.5ml/100g);theHEgroupreceivedHE(125,250or500mg/kg)

(Patiletal.,2011);andtheglibenclamidegroupreceived

gliben-clamide(10mg/kg)(Zhaoetal.,2011).Alldrugsweredilutedwith saline(0.9%)inestablisheddosesandadministeredorallyby gav-ageinavolumeof0.5ml/100gbodyweight(Trovatoetal.,1996;

Diehletal.,2001).Glucoselevelsweremeasuredbeforetherats

receivedthetreatment(zerotime)and30minafterglucosewas administrated(4g/kg)(Alametal.,2011;Pereiraetal.,2012).Blood sampleswerecollectedfromthetailveinjustpriortoand30,60 and180minafterglucoseloading,andtheglucoselevel(mg/dl) wasassayedbyaglucometer(Accu-Chek® _Performa)._At_the_end

oftheexperimentalperiod,theanimalswereanesthetizedwith amixtureoflidocaineandsodiumthiopental(10and150mg/kg, respectively).Bloodaliquotswerecollectedforbiochemical analy-sesviacardiacpuncture,andtheanimalsweretheneuthanizedby exsanguination(Concea,2012).Theliverandsoleuswerecollected forlateranalysis,aswasasegmentofthesmallintestine.

Glycogenmeasurements

Theharvestedliverandsoleuswereassessedforglycogen con-tent3haftertreatment.Glycogenwasisolatedfromthesetissues asdescribedbyKrisman(1962).Thetissuewasweighed, homoge-nizedin33%KOH,andboiledat100◦_C_for₃₀_min,_with_occasional

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Disaccharidaseextractionandassays

Theextractedsmallintestinesegmentwaswashedin0.9%NaCl solution,dried onfilterpaper,weighed,trimmed, and homoge-nized(300×g)with0.9%NaCl(400mgofduodenumper1.0mlof 0.9%NaCl)for1minat4◦_C._The_resulting_extract_was_centrifuged

at(1300×g)for8min.Thesupernatantwasassessedtomeasure

invivo maltase,sucrase,and lactase activityas wellas protein determination.The activityofmaltase(EC 3.2.1.20),lactase (EC 3.2.1.23),andsucrase(EC3.2.1.48)wasdeterminedusingaglucose diagnosiskitbasedonthereagentglucoseoxidase.Todetermined isaccharidaseactivity,duodenumhomogenates(10␮l)were incu-batedat37◦_C_for₆₀_min_with₁₀_␮_l_of_the_substrate_(equivalent_to

0.056␮Mofmaltase,sucrase,orlactase)(Dahlqvist,1984;Pereira etal.,2011).Oneenzymeunit(U)wasdefinedastheamountof enzymethatcatalyzedthereleaseof1␮molofglucoseperminute undertheassayconditions.Thespecificactivitywasdefinedas enzymeactivity(U)permilligramofprotein.Proteinconcentration wasdeterminedbythemethoddescribedbyLowryetal.(1951), usingbovineserumalbuminasthestandard.Theassayswere per-formedinduplicatealongwithappropriatecontrols.

Biochemicalanalysisofserumsamples

Uponcollection,serumsampleswereimmediatelycentrifuged (3000×g)for15min.SerumTCandALTlevelsweredetermined by enzymatic colorimetric methods (UV/vis) using commercial Labtest®_kits_according_to_the_{manufacturer’s}_{instructions.}_A

semi-automatedanalyzer(BioSystems®_,_model_BTS₃₁₀₎_was_used_for_all

analysis(Lietal.,2012).

Statistics

Allresultsshownarepresentedasmeanvalues±SEM.Thedata wereevaluatedbyone-wayANOVAfollowedbyTukey’stestand correlationanalysesusingSPSS20.0.Ap-valueof<0.05was con-sideredstatisticallysignificant.

Results

ChemicalconstituentsofS.chilensis

TheamountofquercetrininHEwasquantifiedbyHPLCusing ananalyticalcurve(r=0.999;y=0.735x=2.6971)witharetention timeof10.02min.TheHPLCanalysisrevealedthequercetrin con-centrationtobe2.4%intheaerialpartsofS.chilensis(Fig.1).

DeterminationofDPPHradicalscavengingactivity

TheDPPHassayshowedthatHEexhibitsantioxidantproperties

invitro(Fig.2).ThehighestscavengingeffectwasobservedforHE, withanIC50of59.12±3.14␮g/ml,althoughitshowedlower scav-engingabilitiesthanascorbicandgallicacids,whichwereusedas standards(16.32±2.94and2.14±1.58␮g/ml,respectively).

EffectofHEontheoralglucosetolerancecurve

Table1showsthatHE500hadasignificantantihyperglycemic

effectwhencomparedtotheCgroup(F(4,21)=12.0;p<0.05).Lower serumglucose (approx. 22%lower) wasdetected180minafter treatment;glibenclamideshowedsimilarresults.

EffectofHEonhepaticandsoleusglycogencontent

Fig.3showsthatHEandglibenclamidedidnotaffecthepaticand soleusglycogencontentcomparedwithothertreatmentgroups.

20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

–10 RT [min]

Extrato bruto1.DATA mAU 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

–10 RT [min]

Padrão Quercetrina1_16_9_2013 20_02_25.DATA mAU

A

B

Fig.1. Analysisbyhighperformanceliquidchromatography(HPLC):A.quercetrin (200␮g/ml);B.hydroalcoholicextractfromaerialpartsofSolidagochilensis(1mg/ml inMeOH)(RT:10.02min).HPLCVarian®_,_Kromasil®_ODS_column₍₅_␮_M)_reversed

phaseC-18(25mm×4.5mm)at24±2◦_C._Two_solvent_systems_used_for_analysis;

H2O:aceticacid(40:1,v/v)(solventA)andCH3CN(solventB).Theflowwas1ml/min, andthegradientusedhad86%ofAfor15min,65%ofAfor20min,and100%ofB for2min.ThedetectionbyUVwasrealizedat360nm.

0 50 100 150 200 250

0 50 100 150 HE Ascorbic acid

Gallic acid

Concentration (g/ml)

% i nh ib it io n o f D P P H

Fig.2.2,2-Diphenyl-1-picrylhydrazyl(DPPH)radicalscavengeractivityof hydroal-coholicextractfromSolidagochilensis(HE)comparedwithstandardsascorbicand gallicacids.Resultsareexpressedasmeans±SEM(n=3).

However, HE 500 significantly increased hepatic (F(4,25)=6.6;

p<0.05)andsoleus(F(4,23)=3.9;p<0.05)glycogencontent com-paredwithgroupC.

EffectofHEondisaccharidaseactivity

DisaccharidaseactivitywassignificantlyaffectedbyHEonlyat adoseof250mg/kg,asitinhibitedmaltaseactivity(F(4,24)=3.4;

p<0.05)comparedwithgroupC(Fig.4).

Table1

EffectsofhydroalcoholicextractfromSolidagochilensisonaglucosetolerancecurve (mean±SEM)(n=6).

Groups Glucoselevel(mg/dl)

Initial(timezero) 30min 60min 180min

C 93.6±2.0 128.5±4.6 136.0±1.1 126.0±6.3 HE125 95.5±2.6 144.6±4.9 150.1±12.7 114.2±5.8 HE250 100.8±3.2 151.6±20.2 150.1±6.1 114.2±2.6 HE500 91.0±4.0 148.2±10.1 142.2±1.6 98.2±2.3*

GLIB 93.3±1.1 149.8±5.5 149.3±3.5 78.5±8.9*

C,control;HE,hydroalcoholicextractfromS.chilensis(125,250or500mg/kg);GLIB, glibenclamide(10mg/kg).

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C HE 125 HE 250 HE 500 GLIB 0.00

0.05 0.10 0.15 0.20

*

m

g

of

gl

yc

og

e

n

/g

o

f s

o

le

u

s

m

u

s

c

le

C HE 125 HE 250 HE 500 GLIB

0.0 0.5 1.0 1.5

*

mg

o

f g

ly

c

o

g

e

n

/g

o

f h

e

p

a

tic

ti

ss

ue

Fig.3.EffectofhydroalcoholicextractfromSolidagochilensis(HE;125,250and 500mg/kg)andglibenclamide(GLIB;10mg/kg)onhepaticandsoleusglycogen con-tentinhyperglycemicrats.Valuesareexpressedasmean±SEM(n=6).*p<0.05 one-wayANOVAcomparedtothecontrolgroup(C).

EffectsofHEonTCandALT

Followingtreatment, groupC ratshad higherserumTCthan rats in the other groups. All hyperglycemic rats treated with HE (125, 250or 500) exhibited an accentuated decrease in TC (−36.8%,−36.7%and−41.3%,respectively),comparedwithgroupC

C HE 125 HE 250 HE 500 GLIB 0

50 100 150

*

Ma

lt

a

s

e

a

ct

iv

it

y

un

it

s

/g

of

pr

ot

e

in

Fig.4.EffectofhydroalcoholicextractfromSolidagochilensis(HE;125,250and 500mg/kg)andglibenclamide(GLIB;10mg/kg)onthespecificactivityofmaltase, inasegmentofthesmallintestine.Valuesareexpressedasmean±SEM(n=6). *p<0.05one-wayANOVAcomparedtocontrolgroupsaline(C).

C HE 125 HE 250 HE 500 Glib

0 20 40 60 80

*

* _*

TC

(

m

g/

dl

)

Fig.5.Theeffectsoftreatmentsontotalcholesterol(TC)values(mean±SEM;n=6). Hyperglycemicratsweregivensaline(controlgroup;C)orthefollowingtreatments: hydroalcoholicextractfromSolidagochilensis(HE;125,250or500mg/kg); gliben-clamide(GLIB;10mg/kg).*p<0.05one-wayANOVAcomparedtocontrolgroup saline(C).

(F(4,23)=5.7;p<0.05;Fig.5).TherewasnodifferenceinserumALT activitybetweenthegroups(datanotshown).

Discussion

Diabetesmellitusisachronicmetabolicdisordercharacterized by hyperglycemia. It is associated with alterations in carbohy-drate,protein,andlipidmetabolism(Pereiraetal.,2011).Plants exertantihyperglycemicandhypoglycemicactivityprimarilyvia their ability torestore pancreatictissue function by increasing insulinoutput,inhibitintestinalabsorptionofglucose,orfacilitate metabolitesininsulin-dependentprocesses(Pateletal.,2012).

Thepresentstudyshowedthataglucosedoseof4g/kgcan con-siderablyincreaseratsserumglucoselevels,whichweremitigated bya singleoral doseofHE at 500mg/kg for180minfollowing glucoseadministration.Recently,itwasdemonstratedthatrutin reducesserumglucoselevelsandpotentiatesinvivoinsulin

secre-tion(Kappeletal.,2013);rutinmechanismofactioncanalsobe

explainedbymammalssynthesizingglycogentomaintain appro-priate glucose levels. Glycogen is how mammalsstore glucose for futureuse, mainlyin skeletal musclesand theliver(Jensen etal.,2011).Insulinandglucagonregulateglycogenmetabolism byactivatingandinhibitingseveralenzymesandproteins(Ferrer etal.,2003);thehealthyorganismremovesserumglucoserapidly whenglucoseisinexcess,butinsulin-stimulatedglucosedisposalis reducedinorganismswithinsulinresistanceandtype2DM(Jensen etal.,2011).Inthepresentstudy,ratsadministeredHE500had significantly increasedglycogen contentin theliver and soleus comparedwithratsingroupC,whichhelpedleadtotheHE500rats lowerserumglucoselevels.InagreementwithTorresetal.(1987), thephytochemicalanalysisbyHPLCconfirmedthatthequercetrin flavonoidisthemajorbioactivesubstanceofS.chilensis.Flavonoids mayexert beneficial effects in DMby enhancinginsulin secre-tion;reducingapoptosisandpromotingproliferationofpancreatic

␤-cells;improvinghyperglycemiathroughregulatinghepatocyte glucose metabolism; reducing insulin resistance, inflammation, and oxidative stressin muscleand fat;and increasingglucose uptakein skeletalmuscleand whiteadiposetissue(Babuetal., 2013).ThisfindingisinagreementwithPrasathandSubramanian

(2011),whoreportedtheantidiabeticeffectoftheflavonoidfisetin

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glucosehomeostasisbymodulatingenzymesthatregulate carbo-hydratemetabolism.Itwasalsodemonstratedthatkaempferitrin, themajorflavonoidfoundinBauhiniaforficataLink.,leaves,isable todiminishserumglucoselevelsandincreaseglucoseuptakein theratsoleusasefficientlyasinsulin(Jorgeetal.,2004).Thiseffect couldberelatedtotheincreasedmuscleglycogencontentseenin thepresentstudywiththeHE500treatment.

Inthepresentstudy,we demonstratedthatHE 250reduced maltase activity. Several plants exert antihyperglycemic activ-ity viainhibiting enzymes that hydrolyze carbohydratesin the smallintestine,andtheeffectappearstoinvolveinteractionswith polyphenoliccompounds(MaiandChuyen,2007).AlthoughHE500 moresignificantlyloweredratsserumglucoselevels,itdidnot sig-nificantlyinhibitmaltaseactivity.Thisfindingisinagreementwith

Pereiraetal.(2011,2012),whofoundthathigherdosesofextracts

andsubstances,didnotaffectdisacharidaseactivity.These find-ingsreinforcetheideathatHEaffectsserumglucosebyincreasing glucosestorage(asglycogen)intheliverandmuscle.

RatstreatedwithHE(125,250or500mg/kg)showeddecreased serum TC. A previous study using other plants suggested that theseeffectscanbeattributedtotherestorationoftriacylglyceride catabolism by stimulating lipolytic pathways involving plasma lipoproteinlipase(Xieetal.,2007).Inthepresentstudy,HEcould have stimulated similar effects. Intracellular glucose and lipid metabolicdisordersarethebasisofavarietyofmetabolicdiseases. Glucoseandlipid metabolicdisordersareclosely relatedtothe occurrenceandprogressionofDM,obesity,hepaticsteatosis,and cardiovasculardisease(Mengetal.,2013).

WecannotdiscountthepossibilitythatHEalsointerfereswith cholesterol’smetabolic cycle at otherpoints, suchas intestinal uptake,endogenousmetabolism,andtransportbylipoproteins(Bei

etal.,2012;Roman-Junioretal.,2015),whichwerenotassessedin

thisstudy.

FreeradicalscavengingpropertiesofS.chilensiswereobserved in the DPPH assay. Thus, we propose that theplants hydroal-coholicextractmayhavecontributedtothehyperglycemicrats improvedlipidmetabolismandoxidativestress.Thisis character-isticofpolyphenols(Liuetal.,2014);however,furtherstudiesare requiredtoconfirmtheinvivoantioxidanteffects ofS.chilensis

anditsbenefitsin hypoglycemicandhypercholesterolemic ani-malmodels.LevelsofALTdidnotdifferbetweentreatmentgroups, indicatingtheabsenceofHEtoxicityatthedosestested.

Insummary,ourresultsshowedthatHEexertedmarked hypo-glycemiceffectsviaincreasingtheproductionandreleaseofinsulin as well as via increasing insulinotropic activity. The hypolipi-demic effect of HE in rats possibly involved reduced levels of lipoproteinsaswellasantioxidantactivity.Furthermore,therewas strongevidencethatquercetrin,themajorconstituentofS.chilensis

extracts,islargelyresponsiblefortheobservedbiologicalactivities. However,theunderlyingmechanismsoftheseeffectsneedtobe elucidatedbyfurtherstudies.

Conclusions

HydroalcoholicextractofS.chilensismaybeeffectivein main-tainingglucosehomeostasisbyreducingserumglucoselevelsand TC.

Conflictsofinterest

Theauthorsdeclarenoconflictsofinterest.

Authorscontribution

MS,APSandMGcontributedinallstepsofthisstudy.EI,FB,GDS, AS,RCandRMcontributedtobiologicalstudies.EF,GPandSMW contributedtobiochemicalanalyses.LZandWARJhaveguidedthe

laboratoryworkand contributedtodesign ofthestudy.Allthe authorshavereadthefinalmanuscriptandapprovedthe submis-sion.

Acknowledgements

ThisworkwassupportedbytheUnochapecó[modalityArt.171 –FUMDES],CNPq-PIBIC(editalN◦_{228/Reitoria/2014),}_PIBIC-FAPE

(editalN◦_{121/Reitoria/2013)}_and_FAPESC.

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