In Vivo and In Vitro Metabolites from the Main Diester and Monoester Diterpenoid Alkaloids in a ...

24 Pages·2015·1.51 MB·English

Hindawi Publishing Corporation
Evidence-Based Complementary and Alternative Medicine
Volume 2015, Article ID 252434, 23 pages
http://dx.doi.org/10.1155/2015/252434
Review Article
In Vivo In Vitro
and Metabolites from the Main
Diester and Monoester Diterpenoid Alkaloids in
Aconitum
a Traditional Chinese Herb, the Species
MinZhang,Chong-shengPeng,andXiao-boLi
SchoolofPharmacy,ShanghaiJiaoTongUniversity,800DongchuanRoad,Shanghai200240,China
CorrespondenceshouldbeaddressedtoXiao-boLi;[email protected]
Received9September2014;Accepted13November2014
AcademicEditor:RojaRahimi
Copyright©2015MinZhangetal.ThisisanopenaccessarticledistributedundertheCreativeCommonsAttributionLicense,
whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkisproperlycited.
Diesterditerpenoidalkaloids(DDAs),suchasaconitine(AC),mesaconitine(MA),andhypaconitine(HA),arebothpharmaco-
logicallyactivecompoundsandtoxicingredientsinatraditionalChineseherb,theAconitumspecies.ManyDDAmetabolism
studieshavebeenperformedtoexploremechanismsforreducingtoxicityinthesecompoundsandinAconitumspeciesextracts
forsafeclinicaladministration.Inthisreview,wesummarizerecentprogressonthemetabolismoftoxicAC,MA,andHAand
corresponding monoester diterpenoid alkaloids (MDAs) in the gastrointestinal tract and liver in different animal species and
humansinvivoand/orinvitro,wherethesealkaloidsareprimarilymetabolizedbycytochromeP450enzymes,carboxylesterases,
andintestinalbacteria,whichproducesphaseImetabolites,esterhydrolysedproducts,andlipoalkaloids.Furthermore,weclassify
metabolitesdetectedinthebloodandurine,wheretheaforementionedmetabolitesareabsorbedandexcreted.LesstoxicMDAs
andnontoxicalcoholaminesaretheprimaryDDAmetabolitesdetectedintheblood.MostotherDDAsmetabolitesproducedin
theintestineandliverdetectedintheurinehavenotbeenreportedintheblood.Weproposeanexplanationforthisnonconformity.
Finally,takingAC,forinstance,wegeneralizeaprocessoftoxicityreductioninthebodyafteroralACadministrationforthefirst
time.
1.Introduction DDA-containing drugs or prescriptions, such as Chuanwu
[5],Caowu[6],andFuzi[7].Therefore,Aconitumherbsare
Diesterditerpenoidalkaloids(DDAs,Table1),suchasaconi- traditionally boiled or steamed before oral administration
tine(AC),mesaconitine(MA),andhypaconitine(HA),area to ensure safety [8]. During this process, DDAs are mainly
familyofhighlytoxicalkaloidsfromtherootofatraditional hydrolysed to less toxic MDAs. Further MDA hydrolysis
Chinese herb, the Aconitum species (sp.), which has been yieldsalmostnontoxicalcoholamines(Table1),suchasaco-
used clinically for years. Monoester diterpenoid alkaloids nine,mesaconine,andhypaconine[3,9,10].Incontrastwith
(MDAs, Table 1) are the ester hydrolysis products of DDAs AC,thehalf-maximallethaldose(LD50,mg/kg,i.v.mice)of
attheC-8position,whicharealsocomponentsofthisherb. 14-benzoylaconine(BAC)andaconineincreasesbyapproxi-
Both DDAs and MDAs exhibit excellent pharmacologi- mately38-and430-fold,respectively[11].
cal effects, including anti-inflammatory, analgesic, and car- Ontheotherhand,manyvaluablestudieshaverecently
diotonicactivities[1,2]. been performed on DDA and MDA metabolism to explore
However,thesecompounds,especiallyDDAs,havenar- the toxicity reduction mechanisms and obtain information
rowtherapeuticwindows.Forexample,asinglelethalACdose for clinical guidance. In this paper, we review for the first
forhumansisestimatedat2–6mg[3,4]withpoisoningsymp- time the metabolites biotransformed in the gastrointestinal
toms, such as hypotension, palpitations, ventricular tachy- tractandliverfromtoxicAC,MA,andHAofDDAsaswell
arrhythmias, asystole, and numbness of the face and limbs as their corresponding ester hydrolysed products, BAC,
[1].Severepoisoningmayoccurafterimproperingestionof 14-benzoylmesaconine (BMA), and 14-benzoylhypaconine
2 Evidence-BasedComplementaryandAlternativeMedicine
Table1:DDA,MDA,andalcoholaminechemicalstructures.
HO OCH3
H3CO 13 16
12
17 14 OR4
1 10 9 15
2 11
R1 3N 5 78 OH
4 6
R2 OR3
19 18
H3CO
OCH3
Compounds R R R R Formula Mass
1 2 3 4
DDAs
Aconitine(AC) Ethyl(Et) Hydroxy(OH) Acetyl(Ac) Benzoyl(Bz) C H NO 645.3149
34 47 11
Mesaconitine(MA) Methyl(Me) OH Ac Bz C H NO 631.2992
33 45 11
Hypaconitine(HA) Me Hydrogen(H) Ac Bz C H NO 615.3043
33 45 10
MDAs
Benzoylaconine(BAC) Et OH H Bz C H NO 603.3043
32 45 10
Benzoylmesaconine(BMA) Me OH H Bz C H NO 589.2887
31 43 10
Benzoylhypaconine(BHA) Me H H Bz C H NO 573.2938
31 43 9
Alcoholamines
Aconine Et OH H H C H NO 499.2781
25 41 9
Mesaconine Me OH H H C H NO 485.2625
24 39 9
Hypaconine Me H H H C H NO 469.2676
24 39 8
(BHA)ofMDAs,indifferentanimalspeciesandhumansin The ester hydrolysis products at the C-8 and C-14 posi-
vivo and in vitro. Furthermore, we classify the metabolites tionsarenotonlyobservedinrabbitstomachsbutalsoinacid
detectedinthebloodandurine,inwhichthesemetabolites solutions(negativecontrol).Esterhydrolysisinthestomach
are absorbed and excreted. Our study will be fundamental may be catalysed by carboxylesterases (CEs) in the gastric
and helpful for further studies on reducing the toxicity mucosa[17]becauseCEexpressionhasalsobeenreportedin
of DDA-containing drugs compatible with other medicine thestomach,althoughCEsarepredominantlydistributedin
basedonDDAsabsorptionandmetabolism[12,13]. theliver,plasma,andintestine[18].However,thisfindingalso
impliesthatDDAscanbenonenzymaticallyesterhydrolysed
2.MetabolismintheGastrointestinal underacidicconditions,whichisdiscussedinSection5.
TractandLiver Inaddition,AC,MA,HA,andtheirhydrolysisproducts
(MDAsandalcoholamines)aredetectedingastriccontents
Traditional Chinese prescriptions are commonly prepared inadeadfemale,whowassuspectedofdyingfromacutedrug
throughdecoctionandingestedorally.Theactivecompounds poisoning involving Aconitum alkaloids [19]. However, the
areunavoidablyconvertedinthegastrointestinaltract. reference did not indicate whether the hydrolysis products
weremetabolizedfromDDAsinthestomachorwereorig-
2.1. Metabolism in the Stomach. The stomach provides an inallyinthetoxicant.
acidicenvironmentfordrugdissolutionandabsorption;how-
ever, studies on stomach metabolism are typically ignored. 2.2.MetabolismintheIntestine. Alargenumberofbacteria
OnlyonestudyhasfocusedonACmetabolisminthestom- populate the gastrointestinal tract; the bacterial concentra-
ach. tion increases distally. The majority of bacteria reside in
11 12
Inthisstudy,14metabolitesand2esterhydrolysisprod- the colon, where the density approaches 10 -10 cells/mL,
ucts are identified in gastric content in rabbits after oral and anaerobic species dominate. This microbiota secretes a
ACadministration[14].Metabolismincludeshydroxylation, diversearrayofenzymesthatparticipateinvariousmetabolic
deoxylation, demethylation, didemethylation/deethylation, processes,suchasreduction,hydrolysis,deoxylation,acetyla-
andesterexchangeattheC-8positionwithlongchainfatty tion,deacetylation,andN-demethylation;thus,theintestinal
acids(Table2).Theenzymesresponsibleformetabolismhave microbiotaisimportanttoorallyingesteddrugmetabolism
not been reported. The aforementioned metabolic process [20,21].Notably,hydrolysiscatalysedbybacteriaiscommon
maybecatalysedbyCYP2C9andCYP2C8thatareexpressed in glycosides. Based on DDA and MDA structures, ester
inparietalgastriccells[15]andbybacteriathatarelocatedin hydrolysis is likely driven by CEs, which also dominate the
thehumanstomach[16]. intestine[18].
Evidence-BasedComplementaryandAlternativeMedicine 3
Table2:ACmetabolitesproducedinrabbitstomachs.
𝑚/𝑧 Neutralloss(Da), Metabolic MS
DDAs Formula Identification identificationoffatty References
(ESI+) procedure detection
acid
󸀠
2-HydroxyACor
3󸀠-AC(M1)a
662 C34H47NO12 3󸀠-HydroxyACor NAb
2󸀠-hydroxyAC(M3)a Rabbitsandrats;
4󸀠-HydroxyAC(M6)a ig,invivo. IT,FT-ICR
632 C H NO DemethylAC(M4) NA
33 45 11
Indaconitine(15-deoxyAC,M5)c
630 C H NO NA
34 47 10
Deoxyaconitine(3-deoxyAC,
M7)
DidemethylACor
AC 618 C H NO NA [14]
32 43 11 N-deethylAC(M2)
Rabbitsandrats;
604 C H NO BAC(hydrolysisproduct2) NA IT,FT-ICR
32 45 10 ig,invivo.
14-O-DebenzoylAC(hydrolysis Rabbitsandrats;
542 C H NO NA IT,FT-ICR
27 43 10 product1) ig,invivo.
242,pentadecanoic
828 C H NO 8-O-PentadecanoylBAC(M10)
47 73 11 acid
842 C H NO 8-O-PalmitoylBAC(M12) 256,palmiticacid
48 75 11
864 C H NO 8-O-LinolenoylBAC(M9) 278,linolenicacid Rabbitsandrats;
50 73 11 IT,FT-ICR
866 C H NO 8-O-LinoleoylBAC(M11) 280,linoleicacid ig,invivo.
50 75 11
868 C H NO 8-O-OleoylBAC(M13) 282,oleicacid
50 77 11
870 C H NO 8-O-StearoylBAC(M14) 284,stearicacid
50 79 11
8-O-HexacosandienoylBAC 392,hexacosandienoic
978 C H NO
58 91 11 (M8) acid
a2󸀠,3󸀠,and4󸀠,thepositioninbenzoylgroup.
bNotavailable.
cDeoxymayalsobereferredtoasdehydroxyintheliterature.
TheintestinalbacteriaDDAmetabolismreviewedherein 8-O-butyryl- (from short chain fatty acid) benzoylmesaco-
wasmainlyperformedinvitrothroughanaerobicincubation nineis15.78mg/kg,whichis5.5-foldgreaterthanMA(8-O-
inafecessuspension,whichincludedhighlevelsofintestinal acetyl-benzoylmesaconine)[22].TheLD50formicewithlipo-
bacteria.TheintestinalbacteriaDDAmetabolismissimilar mesaconitines (from long chain fatty acids) are from 10 to
to metabolism in the stomach and included hydroxylation, 40mg/kg,whichare20-foldgreaterthanMA[32].
deoxylation,demethylation,demethylationwithdeoxylation,
ester hydrolysis at the C-8 and/or C-14 position, and ester
2.3. Metabolism in the Liver. The liver is an important
exchangeattheC-8positionwithshortandlongchainfatty
organ for drug metabolism, and it expresses many drug-
acids(Table3).ACmetabolites,suchas16-O-demethylAC,
metabolising enzymes. After oral administration, drugs are
3-deoxy AC, and 16-O-demethyl-3-deoxy AC, were further
typicallysubjectedtohepaticmetabolism,includingCEsthat
converted to deoxylation, demethylation, ester hydrolysis,
catalyseesterhydrolysis[18],phaseIdrugmetabolicenzymes
and ester exchange products (Table 4). These results imply
thatcatalyseoxidation,andphaseIImetabolicenzymesthat
thatMDAs,whichareDDAesterhydrolysedproducts,may
catalyse conjugation [21]. The metabolites are hydrophilic
bemetabolizedthroughthesamepathway;however,nostud-
and are more rapidly excreted from the body than parent
ieshavereportedonintestinalMDAmetabolism.
drugs. Cytochrome P450 enzymes (CYP450s) and uridine
Esterexchangemetabolitesareclassifiedaslipoalkaloids
󸀠
5 -diphosphate(UDP)-glucuronosyltransferases(UGTs)are
orlipoaconitineswithanacetylgroupattheC-8positionof
themostcommonphaseIandphaseIImetabolicenzymes,
DDAsreplacedbyotherfattyacidacylgroups[24,31].Pre-
respectively[33].
sumably, the short chain fatty acids (such as propionic,
butyric, hexanoic, phenylacetic, and phenylpropionicacids) The hepatic metabolism studies reviewed herein were
for ester exchange are generated from xenobiotics, such mainly performed in vitro through incubation with liver
as food decomposed by intestinal bacteria, while certain microsomes. CYP450- or UGT-catalysed metabolism in
long chain fatty acids (such as palmitic, oleic, and stearic microsomescanbeselectivelyperformedindifferentreaction
acids)aregeneratedfrombacterialcellwalls[24].DDAtoxi- systemswithauxiliaryenzymesandexclusivesubstrates[34,
cityisreducedafteresterexchange.Forexample,theLD50of 35].
4 Evidence-BasedComplementaryandAlternativeMedicine
References [22](P4) [23](M3) [24](M1) [23](M6) [22](P5) [23](M5) [24](M2) [22](P10) [24](M3) [23](M2) [25] [26] [22](P1)
n
o R R R
detecti IT IT FT-IC IT IT IT FT-IC IT FT-IC IT IT IT IT
S T, T, T,
M I I I
d d d d
n n n n
a a a a
e c e e c c e
obic ntestin aerobi ntestin obic ntestin aerobi obic aerobi ntestin obic obic obic
vertedinintestine. Metabolicprocedure Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Rabbits;contentsfromsmallicaecumandfeces;ig,invivo.Human;intestinalbacteria;anincubation,invitro.Rabbits;contentsfromsmallicaecumandfeces;ig,invivo.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Rabbits;contentsfromsmallicaecumandfeces;ig,invivo.Human;intestinalbacteria;anincubation,invitro.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Human;intestinalbacteria;anincubation,invitro.Rabbits;contentsfromsmallicaecumandfeces;ig,invivo.Rats;intestinalbacteria;anaercincubation,invitro.Rats;intestinalbacteria;anaerdincubation,invitro.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.
n
o
c
A
H y
nd ),fatt
A,a (Danof
M so
AC, allosficati
olitesof Neutridentiacid aNA NA NA NA NA
b
a
Met bC) ∗C
Table3: Identification 10-HydroxyAC ∗16-O-DemethylAC ndaconitine(15-deoxyA ∗DeoxyAC 16-O-Demethyl-deoxyA BAC
I
a O12 O11 O10 O10 O10
ul N N N N N
orm H47 H45 H47 H45 H45
F C34 C33 C34 C33 C32
)
+
SI
E 2 2 0 6 4
𝑧( 66 63 63 61 60
/
𝑚
s
A
D C
D A
Evidence-BasedComplementaryandAlternativeMedicine 5
References [23](M1) [22](P2) [25,26] [24] [27] [22](P8) [24] [27] [22](P9) [24] [27] [24] [22](P7) [22](P11) [24] Ibid.
R R R
C C C
I I I
T- T- T-
n F F F
o R e- R e- R e- R R
Sdetecti IT IT IT T,FT-IC DIsourc IT T,FT-IC DIsourc IT T,FT-IC DIsourc T,FT-IC IT IT T,FT-IC Ibid.
M I L I L I L I I
A A A
M M M
T, T, T,
I I I
d
n
a
e c c c c c
ntestin obic obic aerobi obic obic aerobi obic obic aerobi obic aerobi obic obic aerobi
ntinued. Metabolicprocedure Rabbits;contentsfromsmallicaecumandfeces;ig,invivo.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Rats;intestinalbacteria;anaerc,dincubation,invitro.Human;intestinalbacteria;anincubation,invitro.Rats;intestinalbacteria;anaereincubation,invitro.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Human;intestinalbacteria;anincubation,invitro.Rats;intestinalbacteria;anaereincubation,invitro.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Human;intestinalbacteria;anincubation,invitro.Rats;intestinalbacteria;anaereincubation,invitro.Human;intestinalbacteria;anincubation,invitro.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Rats;intestinalbacteria;anaerincubationatpH7.0,invitro.Human;intestinalbacteria;anincubation,invitro.Ibid.
o
C y
Table3: Neutralloss(Da),identificationoffattacid NA NA NA 74,propionicacid NA NA 88,butyricacid NA NA 102,valericacid NA 114,hexenoicacid NA NA 116,hexanoicacid 130,heptanoicacid
C
A
B
AC AC C C AC ryl AC AC
Identification 16-O-DemethylB 15-DeoxyBAC DeacetoxyAC 8-O-PropionylB 8-O-ButyrylBA 8-O-ValerylBA 8-O-HexenoylB (3-Hydroxy)-buty 8-O-HexanoylB 8-O-HeptanoylB
-
O
-
8
a O10 O9 O9 O11 O11 O11 O11 O12 O11 O11
ul N N N N N N N N N N
orm H43 H45 H43 H49 H51 H53 H53 H51 H55 H57
F C31 C32 C32 C35 C36 C37 C38 C36 C38 C39
)
+
SI
E 0 8 6 0 4 8 0 0 2 6
𝑧( 59 58 58 66 67 68 70 69 70 71
/
𝑚
s
A
D C
D A
6 Evidence-BasedComplementaryandAlternativeMedicine
s
Reference [24] [27] [22](P3) [24] Ibid. Ibid. Ibid. Ibid. Ibid. Ibid. [24] [25,26] [24] Ibid.Ibid. Ibid. Ibid. Ibid.
R
C
I
T-
n F
o R e- R R R
Sdetecti T,FT-IC DIsourc IT T,FT-IC Ibid. Ibid. Ibid. Ibid. Ibid. Ibid. T,FT-IC IT T,FT-IC Ibid.Ibid. Ibid. Ibid. Ibid.
M I L I I I
A
M
T,
I
c c c c
bi bi bi bi
o c c o o c o
er bi bi er er bi er
a o o a a o a
n r r n n r n
ria;a anae anaevitro.ria;a ria;a anae ria;a
ntinued. Metabolicprocedure Human;intestinalbacteincubation,invitro.Rats;intestinalbacteria;eincubation,invitro.Rats;intestinalbacteria;incubationatpH7.0,inHuman;intestinalbacteincubation,invitro.Ibid. Ibid. Ibid. Ibid. Ibid. Ibid. Human;intestinalbacteincubation,invitro.Rats;intestinalbacteria;c,dincubation,invitro.Human;intestinalbacteincubation,invitro.Ibid.Ibid. Ibid. Ibid. Ibid.
Table3:Co Neutralloss(Da),identificationoffattyacid 136,phenylaceticacid NA NA 150,phenylpropionicacid214,tridecanoicacid228,tetradecanoicacid242,pentadecanoicacid256,palmiticacid268,heptadecenoicacid270,methylpalmiticacid 280,linoleicacid NA 282,oleicacid 284,stearicacid296,nonadecene300,3-hydroxystearicacid368,tetracosanoicacid376,pentacosatrienoicacid
C
Identification 8-O-PhenylacetylBAC 8-O-OctenoylBAC 8-O-PhenylpropionylBAC 8-O-TridecanoylBAC 8-O-TetradecanoylBAC 8-O-PentadecanoylBAC 8-O-PalmitoylBAC 8-O-HeptadecenoylBAC 8-O-(Methyl)-palmitoylBAC 8-O-LinoleylBAC 8-O-OleoylBAC 8-O-StearoylBAC8-O-(9)-NonadecenoylBAC -O-(3-Hydroxy)-stearoylBA 8-O-TetracosanoylBAC 8-O-PentacosatrienoylBAC
8
a O11 O11 O11 O11 O11 O11 O11 O11 O11 O11 O11 O11O11 O12 O11 O11
ul N N N N N N N N N N N NN N N N
orm H51 H57 H53 H69 H71 H73 H75 H75 H77 H75 H77 H79H79 H79 H91 H87
F C40 C40 C41 C45 C46 C47 C48 C49 C49 C50 C50 C50C51 C50 C56 C57
)
+
SI
E 2 8 6 0 4 8 2 4 6 6 8 02 6 4 2
𝑧( 72 72 73 80 81 82 84 85 85 86 86 8788 88 95 96
/
𝑚
s
A
D C
D A
Evidence-BasedComplementaryandAlternativeMedicine 7
s
eference [25,26] Ibid. [27] Ibid. [25,26] [27] [25,26] [25,26] [27] Ibid.Ibid.Ibid. [25,26]
R
R R R
C C C
I I I
T- T- T-
n F F F
o e- e- e-
Sdetecti IT Ibid. DIsourc Ibid. IT DIsourc IT IT DIsourc Ibid.Ibid.Ibid. IT
M L L L
MA MA MA ma.
T, T, T, zo
I I I hi
R
e
a
al
h
x. p
di ce
a o
R cr
aerobic aerobic aerobic aerobic aerobic aerobic aerobic aerobic mpelopsis ylodisMa
Table3:Continued. Neutralloss(Da),𝑚/𝑧+identificationoffattyMetabolicprocedureDDAs(ESI)FormulaIdentificationacidRats;intestinalbacteria;anNAHNOBMA590Cc,d314310incubation,invitro.NAIbid.572CHNODeacetoxyMA31419MARats;intestinalbacteria;anNA660CHNO8-O-ButyrylBMAe354911incubation,invitro.NAIbid.674CHNO8-O-ValerylBMA365111Rats;intestinalbacteria;anNA852CHNO8-O-LinoleylBMAc,d497311incubation,invitro.Rats;intestinalbacteria;aneincubation,invitro.NAHNOBHA574C31439Rats;intestinalbacteria;anc,dincubation,invitro.Rats;intestinalbacteria;anNA556CHNODeacetoxyHAc,d31418incubation,invitro.HARats;intestinalbacteria;anNA630CHNO8-O-PropionylBHAe344710incubation,invitro.NAIbid.644CHNO8-O-ButyrylBHA354910NAIbid.658CHNO8-O-ValerylBHA365110NAIbid.692CHNO8-O-PhenylacetylBHA394910Rats;intestinalbacteria;anNA836CHNO8-O-LinoleylBHAc,d497310incubation,invitro.aNotavailable.bDeoxymayalsobereferredtoasdehydroxyintheliterature.cDDAwasproducedthroughdecoctionofAconitiRadixCoctawithFritillariaeThunbergiiBulbus,PinelliaeRhizomaPreparatum,andAItisnotclearwhetherthesecompoundsweredirectlymetabolizedfromDDAsorwereoriginallyingested.dDDAwasproducedthroughdecoctionofAconitiLateralisRadixPraeparatawithGlycyrrhizaeRadixandRhizomeaswellaswithAtractItisnotclearwhetherthesecompoundsweredirectlymetabolizedfromDDAsorwereoriginallyingested.eInadditiontoACandHAmonomers,DDAswerealsogeneratedfromethylalcoholextractionofRadixAconiti.ItisnotclearwhetherthesecompoundsweredirectlymetabolizedfromDDAsorwereoriginallyingested.∗Thesemetaboliteswerefurtherbiotransformedintheintestine.MetabolitesoftheseintermediateproductsarelistedinTable4.
8 Evidence-BasedComplementaryandAlternativeMedicine
s
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e 8
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e [
ef
R
n
o R
detecti FT-IC
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intestine. Metabolicprocedure 16-O-DemethylACHNO,632)fro(C334511AC;human;intestinalbacteria;anaerobicincubation,invitro.
e
h
t
n
i
s
e
ationofintestinalACmetabolit Neutralloss(Da),identificationoffattyacidaNANANANANA74,propionicacid88,butyricacid102,valericacid102,methylbutyricacid124,heptatrienoicacid126,heptadienoicacid128,heptenoicacid130,heptanoicacid138,octatrienoicacid144,octanoicacid158,nonanoicacid164,decatetraenoicacid190,dodecapentaenoicacid192,dodecatetraenoicacid194,dodecatrienoicacid206,tridecatetraenoicacid214,methyldodecanoicacid228,tetradecanoicacid282,oleicacid284,stearicacid298,methylstearicacid312,arachidicacid326,heneicosanoicacid354,tricosanoicacid
m
r
o C
Table4:Furtherbiotransf Identification 1,16-DidemethylAC(M1)b16-O-Demethyl-3-deoxyAC(M2)1,16-Didemethyl-3-deoxyAC(M3)16-O-DemethylBAC(M4)16-O-Demethylaconine(M5)16-O-Demethyl-8-O-propionylBAC16-O-Demethyl-8-O-butyrylBAC16-O-Demethyl-8-O-valerylBAC16-O-Demethyl-8-O-(methyl)-butyrylBAC16-O-Demethyl-8-O-heptatrienoylBAC16-O-Demethyl-8-O-heptadienoylBAC16-O-Demethyl-8-O-heptenoylBAC16-O-Demethyl-8-O-heptanoylBAC16-O-Demethyl-8-O-octatrienoylBAC16-O-Demethyl-8-O-octanoylBAC16-O-Demethyl-8-O-nonanoylBAC16-O-Demethyl-8-O-decatetraenoylBAC16-O-Demethyl-8-O-dodecapentaenoylBAC16-O-Demethyl-8-O-dodecatetraenoylBAC16-O-Demethyl-8-O-dodecatrienoylBAC16-O-Demethyl-8-O-tridecatetraenoylBAC6-O-Demethyl-8-O-(methyl)-dodecanoylBA16-O-Demethyl-8-O-retradecanoylBAC16-O-Demethyl-8-O-oleoylBAC16-O-Demethyl-8-O-stearoylBAC16-O-Demethyl-8-O-(methyl)-stearoylBAC16-O-Demethyl-8-O-arachidylBAC16-O-Demethyl-8-O-heneicosanoylBAC16-O-Demethyl-8-O-tricosanoylBAC
1
a O11O10O10O10O9O11O11 O11 O11O11O11O11O11O11O11O11O11O11O11O11O11O11O11O11O11O11O11O11
ul NNNNNNN N NNNNNNNNNNNNNNNNNNNN
orm H43H45H43H43H39H47H49 H51 H49H51H53H55H51H57H59H53H55H57H59H59H67H69H75H77H79H81H83H87
F C32C33C32C31C24C34C35 C36 C38C38C38C38C39C39C40C41C43C43C43C44C44C45C49C49C50C51C52C54
)
+
SI
E
(
𝑚/𝑧 618616602590486646660 674 696698700702710716730736762764766778786800854856870884898926
Evidence-BasedComplementaryandAlternativeMedicine 9
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Metabolicprocedure 3-DeoxyAC(CHNO,344710630)fromAC;human;intestinalbacteria;anaerobicincubation,invitro. 16-O-Demethyl-3-deoxyHNO,616)froAC(C334510AC;human;intestinalbacteria;anaerobicincubation,invitro.
4:Continued. Neutralloss(Da),identificationoffattyacidNANANANA74,propionicacid88,butyricacid130,heptanoicacid132,2-methyl-3-hydroxyvalericacid144,octanoicacid160,3-hydroxyoctanoicacid176,undecapentaenoicacid192,dodecatetraenoicacid216,hydroxydodecanoicacid230,hydroxytridecanoicacid244,hydroxytetradecanoicacid258,hydroxypentadecanoicacid284,stearicacidNANANANA74,propionicacid88,butyricacid140,octadienoicacid144,octanoicacid146,hydroxyheptanoicacid174,hydroxynonanoicacid190,dodecapentaenoicacid206,tridecatetraenoicacid222,tetradecatrienoicacid
e
l
Tab ACACCCC
C BBAAA
Identification 16-O-Demethyl-3-deoxyAC(M1)1,13-DideoxyAC(M2)3-DeoxyBAC(M3)3-Deoxyaconine(M4)3-Deoxy-8-O-propionylBAC3-Deoxy-8-O-butyrylBAC3-Deoxy-8-O-heptanoylBAC 3-Deoxy-8-O-(2-methyl-3-hydroxy)-valerylBA 3-Deoxy-8-O-octanoylBAC3-Deoxy-8-O-(3-hydroxy)-octanoylBAC3-Deoxy-8-O-undecapentaenoylBAC3-Deoxy-8-O-dodecatetraenoylBAC3-Deoxy-8-O-(hydroxy)-dodecanoylBAC3-Deoxy-8-O-(hydroxy)-tridecanoylBAC3-Deoxy-8-O-(3-hydroxy)-tetradecanoylBAC3-Deoxy-8-O-(hydroxy)-pentadecanoylBAC3-Deoxy-8-O-propionylBAC1,16-O-Didemethyl-3-deoxyAC(M1)16-O-Demethyl-3-deoxy-deoxyAC(M2)16-O-Demethyl-3-deoxyBAC(M3)16-O-Demethyl-3-deoxyaconine(M4)16-O-Demethyl-3-deoxy-8-O-propionylBAC16-O-Demethyl-3-deoxy-8-O-butyrylBAC16-O-Demethyl-3-deoxy-8-O-octadienoylBAC16-O-Demethyl-3-deoxy-8-O-octanoylBAC16-O-Demethyl-3-deoxy-8-O-(hydroxy)-heptanoyl16-O-Demethyl-3-deoxy-8-O-(hydroxy)-nonanoyl16-O-Demethyl-3-deoxy-8-O-dodecapentaenoylB16-O-Demethyl-3-deoxy-8-O-tridecatetraenoylB16-O-Demethyl-3-deoxy-8-O-tetradecatrienoylB dehydroxyintheliterature.
as
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Formula CHNO334510HNOC34479CHNO32459CHNO25418CHNO354910CHNO365110CHNO395710 CHNO385511 CHNO405910CHNO405911CHNO435510CHNO445910CHNO446711CHNO456911CHNO467111CHNO477311CHNO507910CHNO324310HNOC33459CHNO31439CHNO24398CHNO344710CHNO354910CHNO395310CHNO395710CHNO385511CHNO405911CHNO435510CHNO445910CHNO456310 obereferredt
+ESI) ailable.mayals
( avxy
𝑚/𝑧 616614588484644658700 702 714730746762786800814828854602600574470630644696700702730746762778 NotDeo
a b
10 Evidence-BasedComplementaryandAlternativeMedicine
The DDA and MDA phase I metabolic pathways are afecessuspension,despitethesymbioticintestinalbacteria,
similar and include hydroxylation, deoxylation, demethy- which should also contain apoptosis-undergoing intestinal
lation, didemethylation/deethylation, dehydrogenation, and epithelial cells that release phase I and phase II metabolic
demethylation with dehydrogenation (Table 5). The indi- enzymes into the suspension. Thus, intestinal metabolites
vidual CYP450s responsible for specific metabolites were arelikelyconvertedby bothbacteriaandphase Imetabolic
furtherdeterminedviaindividualinhibitorsorrecombinant enzymes.
isoenzymes. CYP3A4 and CYP3A5 are the most common Metabolic isoenzyme expression is not identical among
isoenzymes that catalyse both DDAs and MDAs. In addi- different species [50] that lead to metabolic differences in
tion,CYP2D6,CYP1A1/2,CYP2C9,CYP2C8,CYP2C19,and differentspecies.Basedonreferencesinthisreview,wefind
CYP2E1alsopartiallycatalyseDDAs. that DDAs were ester hydrolysed to MDAs in rat intestine
Hydrophobicdrugbiotransformationcommonlyoccurs and liver, but not in humans. On the other hand, the same
firstthroughphaseImetabolisminwhichfunctionalgroups, metabolitesconvertedindifferentspecieshavebeenreported.
such as hydroxy, sulfhydryl, carboxyl, and amino group, For example, 16-O-demethyl BAC, the ester hydrolysed
are formed and provide reaction sites for the subsequent productsfrom16-O-demethylACinintestinalmetabolism,
phase II conjugation [46, 47]. For lipophilic DDAs and was detected not only in rats but also in humans. Hydroxy
MDAs,hydroxygroupsareinitiallypresentandareformed aconitinefromACwasdetectedthroughincubationinliver
afterhydroxylationduringthephaseImetabolism.However, microsomesorS9fromhumans,rats,guineapigs,andmice.
phase II metabolites of either DDAs or MDAs were not ItisnotablethattheACdemethylationattheC-16positionis
detected in hepatic metabolism in vitro and in vivo, which catalysedbyCYP3AandCYP1A1/2inratswhileitiscatalysed
demonstrates that phase II metabolism is not dominant byCYP3A,CYP2D6,andCYP2C9inhumans.However,no
compared with phase I metabolism in the liver. DDA ester studieshavespecificallycomparedmetabolitesfromDDAsor
hydrolysis should be catalysed by CEs. However, CYP3A, MDAs among humans and different experimental animals.
CYP1A1,andCYP1A2arealsoinvolvedinesterhydrolysisof Briefly, the metabolic differences in different species yield
AC,whichreflectsthecomplexityofmetabolism. certainrisksinpredictinghumandrugmetabolismbasedon
datafromexperimentalanimals.
2.4. A Comparison of DDA and MDA Metabolism in the
ThemetabolicpathwaysproposedforDDAsaregeneral-
Gastrointestinal Tract and Liver. The metabolites generated
izedinFigure1.
inthestomach,intestine,andliverarecomparedinTable6.
The organ/tissue metabolic processes are partially indi-
The polarity of most metabolites increased after DDA gas-
cated.Thewavybondsindicatethepotentialmetabolicposi-
trointestinal and hepatic metabolism, except lipoalkaloids.
tions. Me, Et, Ac, and Bz indicate methyl, ethyl, acetyl, and
Metabolites of AC from dehydrogenation and demethyla-
benzoylgroups,respectively.
tion with dehydrogenation were only observed in the liver.
The AC metabolites from demethylation with deoxylation
observed from intestinal bacteria incubation [24] were also 3.MetabolitesDetectedintheBlood
detectedintheurineafteroralACadministrationinrabbits.
However,thesemetaboliteswerenotfoundintheurineafter MDAs and alcohol amines are the main DDA metabolites
intravenousinjection[48].Thisobservationsuggeststhatthe in the blood (Table 7). It has been suggested that AC
gastrointestinal tract may participate in biotransformation. and related alkaloids can be rapidly absorbed by the upper
The characteristic metabolites in the gastrointestinal tract gastrointestinaltractfortheshortlatentperiodbetweenthe
were lipoalkaloids, which might be converted by enzymes ingestionofaconiterootsandtheonsetofpoisoningfeatures
that are only produced by intestinal bacteria. In addition, [3]. Therefore, the absorbed DDAs may be partially and
morelipoalkaloidvarietiesweredetectedintheintestinethan graduallyesterhydrolysedtolesstoxicMDAsandnontoxic
inthestomach,whichisconsistentwithabundantbacterial alcoholaminesbyCEsdistributedintheblood.Furthermore,
distribution in the gastrointestinal tract [16]. More studies the blood provides a suitable pH environment for ester
havefocusedonDDAsthanMDAs.However,itisspeculated hydrolysis. This hypothesis is supported by an analysis of
that MDAs may share similar metabolic pathways (except ratplasmaafterDDAadministrationviaatailvein,wherein
for ester hydrolysis at the C-8 position) with DDAs in the MDAsandalcoholaminesweredetected[39].
gastrointestinaltractbasedonthesimilarityintheirhepatic MDAs and alcohol amines are commonly considered
metabolismandchemicalstructures. markers in forensic and clinical evaluations of aconitine
Interestingly, phase I metabolites of hydroxylation, poisoningbecausetheirhalf-livesarelongerthanDDAs[19],
deoxylation, demethylation, and didemethylation/deethyla- which might lead to the neglect of other metabolites in the
tion were detected not only in the liver but also in the gas- blood.Additionally,manyefflux/influxtransporters,suchas
trointestinaltract.AsmentionedaboveinSection2.2,intesti- P-glycoprotein (P-gp), multidrug resistance-associated pro-
nalbacteriaparticipateinmetabolism,suchasthroughdeox- tein 2 (MRP2), and MRP3 expressed in intestinal epithelial
ylation, reduction, and deacetylation. However, it has also and hepatic cells, are involved in drug absorption [53]. It
been reported that human small intestinal epithelial cells is difficult to determine whether the various metabolites
express a range of P450s, which include CYP3A, the isoen- produced in the gastrointestinal tract and liver are trans-
zymethatdominatesintheliver[49].Intestinalmetabolism portedintothebloodfromthefewstudiesontheirtransport
was performed in vitro through anaerobic incubation in mechanism.