Boswellia B. papyrifera (Del.) Hochst., B. neglecta S. B ...4 ISRNAnalyticalChemistry 6 7 8 9 10 11...

Research ArticleComparative Phytochemical Analyses of Resins ofBoswellia Species (B papyrifera (Del) Hochst B neglecta SMoore and B rivae Engl) from Northwestern Southern andSoutheastern Ethiopia

Deribachew Bekana1 Tesfahun Kebede1 Mulugeta Assefa1 and Habtemariam Kassa2

1 Department of Chemistry College of Natural and Computational Sciences Haramaya University PO Box 138 Dire Dawa Ethiopia2 Centre for International Forestry Research Ethiopia Office PO Box 5689 Addis Ababa Ethiopia

Correspondence should be addressed to Deribachew Bekana gado430yahoocom

Received 2 September 2013 Accepted 11 November 2013 Published 13 February 2014

Academic Editors A Bouklouze A Garcia Asuero and R N Rao

Copyright copy 2014 Deribachew Bekana et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Oleogum resins of B papyrifera B neglecta and B rivae were collected from northwestern southern and southeastern Ethiopiaand their respective methanol extracts and essential oils were extracted and analyzed by gas chromatography (GC) and gaschromatography-mass spectrometry (GC-MS)The investigation on essential oils led to the identification of 6 7 and 8 constituentsfor B papyrifera B neglecta and B rivae respectively The essential oil of B papyrifera is mainly characterized by the presence ofoctyl acetate (571ndash657) and n-octanol (34ndash88) B neglecta is rich in 120572-pinene (326ndash507) followed by terpinen-4-ol (175ndash299) and120572-thujene (127ndash165) whereasB rivaewas predominated by120572-pinene (325ndash662) followed by p-cymene (57ndash211)and limonene (11ndash196) Methanol extracts of the three Boswellia species were found to consist of diterpines (incensole incensylacetate and verticilla-4(20)711-triene) triterpenes (120573-amyrin 120572-amyrin 120573-amyrenone and 120572-amyrenone) nortriterpenes (24-noroleana-312-diene and 24-norursa-312-diene) and 120572-boswellic acid The investigation on the methanol extract showed thatonly B papyrifera contains diterpenes and nortriterpenes whereas B rivae and B neglecta consist of only triterpenes The resultsindicate that the three Boswellia species were characterized by some terpenes and these terpenoic constituents could be recognizedas chemotaxonomical markers for each species

1 Introduction

The family Burseraceae is represented by 17 genera and 500ndash600 species widespread in tropical and subtropical regionsThe genus Boswellia has about 25 species of small trees andshrubs occurring in dry land regions from west Africa toArabia and from south to northeast Tanzania in India andone species inMadagascarThe genus is centered in northeastAfricawhere about 75of the species are endemic to the areaThey are trees or shrubs often with latex resins or oils whichare strongly aromatic [1 2]

Frankincense gum olibanum or olibanum are thecommon names given to the oleogum resin which isobtained through incisions made in the trunks of trees ofthe genus Boswellia (family Burseraceae) It is plant product

and belongs to a group of aromatic gums and resins whichcontain odiferous substances [2ndash4]

Frankincense consists of essential oils gum and ter-penoids [5] It is a complex of 30ndash60 alcohol solubleresins (diterpenes triterpenes) 5ndash10 essential oil whichis soluble in organic solvents and the rest is made up ofpolysaccharides (gum) which are soluble in water [2] Itsessential oil portion is composed of ester (621) alco-hol (154) monoterpene hydrocarbons (99) diterpenes(71) [6] and sesquiterpenes Gum fraction is composedof pentose and hexose sugar and resin portion is mainlycomposed of pentacyclic triterpene acid of which boswellicacid is the active moiety [7] Mono- and sesquiterpenes arehighly volatile compounds diterpenes exhibit low volatility

Hindawi Publishing CorporationISRN Analytical ChemistryVolume 2014 Article ID 374678 9 pageshttpdxdoiorg1011552014374678

2 ISRN Analytical Chemistry

triterpenes exhibit very low volatility and polysaccharides arenot volatile [8]

Different commercial varieties of frankincense can bedistinguished by the chemical constituents of their essentialoil The constituents of the essential oil of frankincense werefirst investigated by Stenhouse [9] and he identified fourteenmonoterpenoic constituents Chemical investigation byBasar[2] on the essential oil of B neglecta and B rivae led toisolation and identification of monoterpenes The majorcompounds identified in B neglecta were 120572-thujene (213)120572-pinene (213) sabinene (13) Δ-3-carene (19) p-cymene (118) terpinen-4-ol (53) and verbenone (21)B rivae resin oil composition is quite similar to thatof B neglecta which consists of cara-24-diene (18) 120572-thujene (29) 120572-pinene (167) o-cymene (39) Δ-3-carene (173) p-cymene (32) and limonene (211) Inthe study triterpenoic constituents namely 120572-amyrin (91)120573-amyrin (07) epi-120572-amyrin (16) 120573-amyrenone (14)120572- and 120573-amyrin (3-12-dien-120572-amyrin (34) and 3-12-dien-120573-amyrin (11) were also identified from pyrolysateof B neglecta Similarly 24-norursa-312-diene (187) 120572-amyrin (42) 120573-amyrin (09) 120572-amyrenone (28) 120573-amyrenone (23) and epi-120573-amyrin (09) were detectedin the pyrolysate of B rivae Dekebo et al [10] reported theessential oil constituents of the resin of B papyrifera andidentified n-hexyl acetate (1) 120572-pinene (26) limonene(65) n-octanol (80) linalool (32) octyl acetate (56)caryophyllene oxide (21) and 120573-elemene (29)

Although Ethiopia is one of the few countries that areendowed with large frankincense resources little properexploitation of this resource has been made so far (iethe export market from Ethiopia has been weakened) dueto inconsistent supply and ambiguity of grades [11] Ofthe three Boswellia species found in Ethiopia frankincenseresin obtained from B papyrifera is the most widely tradedfrankincense accounting for over 90 of the natural gumexported The frankincense obtained from B rivae andB neglecta species is yet not of export standard [12] Asreported by Assefa et al [13] basis for selection of exportitem and the respective price quotations need to be revisedto reflect contents of ingredients sought after by buyersEthiopia will be more benefited from the export of theseitems provided efforts are made to develop these resourcesmore than the current situation However there is paucityof information on chemical quality variations between theexport standard frankincense (B papyrifera) and the othertwo Boswellia species (B rivae and B neglecta) which arenot of export standard This study is therefore initiatedfor comparative purpose where essential oil and methanolextract composition of one species were contrasted with theother(s) to characterize the chemical classes of constituentspresent and to find chemotaxonomical markers among theseconstituents for the three Boswellia species

2 Materials and Methods

21 Description of Sampling Sites and Sample Collection Theresin samples of frankincense (Boswellia species) used for this

study were collected in August 2011 from northwestern andsoutheastern Ethiopia From northwestern Ethiopia threesites were selected Metema from Amhara region Humerafrom Tigray regional state and Metekel from BenishangulGumuz regional state From these sites exudates were col-lected from B papyrifera Samples from southeastern partof the country were collected from three districts namelyMega Dubuluk and Wachile from Borana zone of Oromiyaregion In these entire three sites one dominant speciesknown as B neglecta is widely grown Then samples werealso collected from Filtu Chereti and Dolo Odo districts ofSomalia regional state In these sites B rivae was dominantThe studied samples were an authentic sample which arecertified for their authenticity by Agricultural Departmentof the Ethiopian Government Natural Gum Processing andMarketing Enterprise The geographical locations of thedistricts are given in Table 1

22 Chemicals and Reagents All chemicals and reagents usedwere of analytical grade Chloroform (999) and methanol(998) were purchased fromMerck (Darmstadt Germany)Anhydrous sodium sulfate was purchased fromFluka (BuchsSwitzerland)

23 Equipment and Instruments Polyethylene plastic bagsceramic mortar and pestle (Haldenwanger Germany)a digital analytical balance (Mettler Toledo Model AG204 Switzerland) round bottom flask (Mumbai India)Clevenger apparatus (Rac India) rotary evaporator andheating mantle (Buchi Switzerland) Gas chromatography(Monza Italy) Gas chromatography-mass spectrometry(PerkinElmer USA) and syringes (Hamilton Bonaduz AGSwitzerland) are among the equipment and instruments thatwere used in the study

24 Methanol Extraction and Isolation of Essential Oils Theresins of the three Boswellia species were air-dried at roomtemperature for 4 weeks grinded and homogenized to auniform powder by ceramic mortar and pestle and sievedTwo grams of grinded and homogenized resins powder wasextracted with 30mL of methanol at room temperature Theextracts were concentrated using a rotary evaporator andanalyzed by GC-MS For essential oils the ground resins ofthe three Boswellia species B papyrifera B neglecta andB rivae were submitted for 3 h to hydrodistillation using aClevenger-type apparatus The obtained oils were allowed todry over anhydrous sodium sulphate After filtration the oilswere stored at +4∘C until analyzed [4]

25 Gas Chromatography GC analyses were performedon Dani model 1000 Gas chromatography (Monza Italy)equipped with flame ionization detector (FID) The analysiswas carried out on a fused silica capillary column coated withHP-5 column length 30m internal diameter 032mm filmthickness 025 micron and 5 phenyl 95 methyl polysilox-ane as stationary phase The oven was programmed at 50ndash210∘C at a rate of 3∘Cmin using N

2as carrier gas injector

and detector (FID) temperatures were 210∘C and 260∘C

ISRN Analytical Chemistry 3

Table 1 Geographical locations of the study areas

Region Areas Latitude and longitude

NorthwesternMetema 12∘581015840428010158401015840 N 36∘091015840543010158401015840 EMetekel 10461015840490410158401015840 N 35∘331015840568310158401015840 EHumera 10∘461015840490410158401015840 N 35∘331015840568310158401015840 E

SoutheasternWachile 4∘321015840346110158401015840 N 39∘041015840065010158401015840 EDubuluk 4∘211015840432210158401015840 N 38∘161015840178010158401015840 EMega 4∘031015840250610158401015840 N 38∘181015840415810158401015840 E

EasternFiltu 5∘051015840353510158401015840 N 40∘391015840309910158401015840 E

Dolo Odo 4∘201015840455010158401015840 N 42∘121015840822010158401015840 EChereti 5∘211015840570810158401015840 N 41∘491015840415110158401015840 E

Table 2 Chemical compositions () of essential oils of threeB neglecta resins

Retention time (min) Components Dubuluk Mega Wachilelowast

64 120572-Thujene 165 130 12767 120572-Pinene 420 326 50778 120573-Pinene 11 14 1588 Sabinene 07 29 1494 p-Cymene 20 51 22146 Terpinen-4-ol 282 299 175150 Verbenone 36 25 66lowastComponents identified from the essential oil of same sample reported inour previous study [13]

respectively Calculation of peak area percentage was per-formed on basis of the FID signal using the GC HP-Chemstation software (Agilent Technologies)

26 Gas Chromatography-Mass Spectrometry GC-MS analy-seswere performedusing a 500 series PerkinElmerClarusGCcoupled with Perkin Elmer Clarus MS quadrupole analyzermass spectrometer at 70 eV Fused silica capillary column typewas DB-17 (30m times 025mm id) and the oven temperaturewas programmed at 80ndash280∘C at a rate of 10∘Cmin usinghelium as carrier gas injector and detector (FID) tempera-tures were both maintained at 250∘C The constituents wereidentified by matching their 70 eV mass spectra with NISTWiley databases and user generated mass spectral librariesby comparing their corresponding retention time (119905

119877) on

the chromatogram by interpretation of the mass spectrafragmentation data and by comparison of the mass spectraobtained with those of the published literature data [2 10 14ndash19]

3 Results and Discussion

31 Chemical Compositions of the Essential Oils The essentialoils of the resins of B neglecta B rivae and B papyriferawereobtained by hydrodistillation The essential oils obtained assuch were analyzed by GC and their corresponding results(chromatograms) are presented subsequently in Figures 1 2and 3 and Tables 2 3 and 4

5 6 7 8 9 10 11 12 13 14 15 16

00

02

04

06

Inte

nsity

(au

)

Retention time (min)

WachileMega

Dubuluk

Figure 1 Comparison of chromatogram of essential oil of three Bneglecta resins

6 7 8 9 10 11 12 13 14

00

01

02

03

04In

tens

ity (a

u)


Dolo OdoFiltuChereti

Figure 2 Comparison of chromatogram of essential oil of three Brivae resins

32 Chemical Composition of the Methanol Extracts Frank-incense is a complex mixture of essential oils and alcoholsoluble resins and the remaining are water-soluble gumswhich are polysaccharides In this study chemical compo-sitions of methanol extract of resins of the three Boswelliaspecies were investigated by GC-MS and their correspondingchromatograms are presented in Figures 4ndash8

The chromatogram (Figure 4) for the methanol extract ofresin of B neglecta collected from Wachile area revealed onemonoterpene 120572-pinene and three triterpenoic constituents120573-amyrenone 120572-amyrenone and 120572-amyrin The first peakwhich appeared at 633min was identified as 120572-pineneThe components having retention time of 3678 3820 and3893min were identified as 120573-amyrenone 120572-amyrenoneand 120572-amyrin respectively The chromatographic profile(Figure 5) of the methanol extract of B rivae resin collected


6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

000

005

010

015

020

025

Inte

nsity

(au

)


MetemaMetekelHumera

Figure 3 Comparison of chromatogram of essential oil of three ofB papyrifera resins

Table 3 Chemical compositions () of essential oils of three ofB rivae resins

Retentiontime (min) Components Dolo Odo Filtu Cheretilowast

64 120572-Thujene 100 23 1767 120572-Pinene 662 373 32578 o-Cymene 26 56 3091 Δ-3-Carene 07 67 6295 p-Cymene 57 98 21197 Limonene 11 97 196134 120572-Campholene aldehyde 18 15 16136 trans-Verbenol 29 29 17lowastComponents identified from the essential oil of same sample reported inour previous study [13]

Table 4 Chemical compositions () of essential oils of three ofB papyrifera resins

Retentiontime (min) Components Metekel Metema Humeralowast

64 120572-Pinene 09 20 23104 Limonene 14 21 38111 n-Octanol 34 47 88121 Linalool 10 11 21158 Octyl acetate 571 657 604181 Geraniol 14 08 25lowastComponents identified from the essential oil of same sample reported inour previous study [13]

from Chereti area evidenced the presence of one monoter-pene 120572-pinene and two triterpenoic constituents 120573-amyrinand 120572-amyrin The components which had retention timeof 638 3747 and 3813min were identified as 120572-pinene 120573-amyrin and 120572-amyrin respectively

100

0

()

600 1100 1600 2100 2600 3100 3600Time

633

2888 3678

3820

3893

Figure 4 Chromatogram of methanol extract of B neglecta resinofWachile origin

638

2799

37473813

3888

100

0

()

600 1100 1600 2100 2600 3100 3600Time

Figure 5 Chromatogram of methanol extract of B rivae resin ofChereti origin

Another species studied was B papyrifera the resin ofwhichwas collected fromnorthern part of Ethiopia (MetemaMetekel and Humera areas) The methanol extract of Bpapyrifera resin was found to be composing one diter-pene and three triterpenes The chromatogram (Figure 6)of methanol extract of B papyrifera resin collected fromHumera area revealed components with retention timeof 2087 2483 2495 and 2625min which were identi-fied as incensyl acetate 120573-amyrenone 120573-amyrin and 120572-amyrin respectively For those collected from Metekel areathe chromatographic profile (Figure 7) revealed compo-nents with retention time of 2041 2178 2187 3047 and3128min and were recognized as verticilla-4(20)711-trieneincensole incensyl acetate 24-noroleana-312-diene and 24-norursa-312-diene respectively whereas the chromatogram(Figure 8) of methanol extract of B papyrifera resin collectedfrom Metema area revealed components with retention timeof 2090 and 2644min and these were identified as incensylacetate and 120572-boswellic acid respectively

33 Interpretation of Mass Spectra of the Identified Compo-nents In the present study the identified components wereconfirmed by interpretation of their mass spectra (MS)


100

()

2087

2483

2495

2625

2703

300 700 1100 1500 1900 2300 2700 3100Time

0

Figure 6 Chromatogram of methanol extract of B papyrifera resinof Humera origin

100

0

()

600 1100 1600 2100 2600 3100 3600Time

2041

2187

2178

30473128

3718

Figure 7 Chromatogram of methanol extract of B papyrifera resinof Metekel origin

Some chemical compositions of methanol extract of frank-incense samples examined were found to be very similarand the identified compounds have already been reportedfrom similar and other species of Boswellia as well as inother plants Most of them are triterpenes which belong tothe oleanane or ursane series and are characterized by abase peak at 119898119911 = 218 Hence to avoid confusion oninterpreting mass spectra of terpenes identified analyticalreview on the base peaks main fragments and fragmentationpatterns of the skeleton of terpenes identified was presentedThe fragmentation patterns of pentacyclic triterpenoid com-pounds having a double bond at position 12 (12-oleananetype and 12-ursane type) show similar fragment at 119898119911 =218 which is formed by Retro-Diels-Alder (RDA) fragmentThe MS of 12-ursane type triterpene resembles that of 12-oleanene type The compounds have been identified by theirretention time and mass spectral comparison 12-Ursane and12-oleanene type pentacyclic triterpenes undergo primarilyRDA fragmentation The RDA fragment including rings Dand E of both types of compounds altered only in theposition of a single methyl group at C-20 In 12-ursane typetriterpenes C-17 C-19 and C-20 were occupied with methylgroups whereas in 12-oleanene types C-20 was occupiedwith two methyl groups The retention time is influenced

100

()

300 700 1100 1500 1900 2300 2700 3100Time

01954

2090

2644

2953

Figure 8 Chromatogram of methanol extract of B papyrifera resinof Metema origin

by the number and the type of functional groups presentand generally increases with increasing molecular weight oftriterpenes [17] Depending on the absolute configuration120572-configuration (ursane type) was found to have longerretention time than 120573-configuration (oleanane type) due toshift of the CH

3group from an axial conformation at C-20

in oleanane structures to an equatorial conformation at C-19in ursane type compounds which caused an increase in theplanarity of the molecules that related to their retention time[2] Comparison in theirMS between peaks at119898119911 = 203 and119898119911 = 189 allows making the distinction between oleananeand ursane type triterpenes But a loss of a methyl groupproduced the signal at 119898119911 = 203 for both compoundsHowever the later fragment was more abundant in the massspectrum of oleanane type than ursane type This happensbecause of more stable tertiary carbenium ion formed inoleanane type of triterpenes than the secondary carbeniumion formed in ursane type of triterpenes as a result of methylcleavage [2] As reported by Mathe et al [17] for oleanenederivative the fragment ion at 119898119911 = 203 is more intensethan the peak at 119898119911 = 189 while for identical ursanederivatives both peaks have almost similar intensities in theirmass spectra

Accordingly the two components identified in this studyas 120573-amyrenone and 120572-amyrenone showed molecular ionpeaks (M+) at 119898119911 = 424 in their mass spectrum which isconsistent with molecular formula of C

30H48O However the

abundant ions at119898119911 218 203 205 409 and 189 are typical forthe fragmentation of 120573-amyrenone and 120572-amyrenone Bothcompounds showed similar MS and their mass spectrumshows a typical fragmentation pattern of ursane and oleananetype triterpenes Finally identification was made by compar-ing their retention time and intensity of signal at 119898119911 = 189and119898119911 = 203 Therefore the component which had shorterretention time and more intense peak at 119898119911 = 203 wasassigned as 120573-amyrenone and 120572-amyrenone was found tobe compound with longer retention time and similar peaksignal intensity at119898119911 = 189 and 203 Possible fragmentationpattern for 120573-amyrenone is presented in Figure 9

Compounds identified as 120573-amyrin and 120572-amyrin pro-duced molecular ion peak signal at 119898119911 = 426 in their mass


HH

OH

HOminusCH3

mz = 409mz = 424

RDA

mz = 218

minusCH3

mz = 203

minusCH2CH3

mz = 189

Omz = 205

∙+

CH2

Figure 9 Possible fragmentation patterns for 120573-amyrenone

mz = 426

mz = 411

mz = 218

mz = 203

mz = 189

mz = 393

mz = 207

mz = 409

H

H

H

H

minusCH3

minusCH3

minusOH

minusH2O

OH

OH

CH2

RDA

∙+

Figure 10 Possible fragmentation patterns for 120572-amyrin

spectrum that corresponded to an elemental compositionof C30H50O Similar to that of amyrenone derivative they

produced similar MS The difference of two in the massunit indicates exchange of a keto group for a hydroxy groupwhich leads to an increase of molecular weight and polarityAs a consequence this compound had longer retentiontime than derivative of amyrenone 120572- and 120573-Amyrin weredifferentiated by examination of the relative intensities ofthe peaks at 119898119911 = 189 and 203 120573-Amyrin had highintensity peak at 119898119911 = 203 which is around twice thatof 119898119911 = 189 peak while 120572-amyrin spectra show similarintensity for both peaks which was consistent with the earlierresults [2] Generally the 120572-amyrin triterpene possesses abasic skeleton of the ursane type and the 120573-amyrin triterpenepossesses a basic skeleton of the oleanane type and the onlydifference between them is the methyl position in the E-ringAccordingly the possible fragmentation pattern for120572-amyrinis shown in Figure 10

Two nortriterpenes (24-norursa-312-diene and 24-noroleana-312-diene) identified from resin of B papyriferaproduced molecular ion (M+) peak signal at 119898119911 = 394in their mass spectrum that corresponded to an elementalcomposition of C

29H46 Both compounds showed similar

mz = 394

mz = 218

mz = 203

mz = 175

mz = 161

minusCH3

minusCH3

H

H

H

+∙

+

Figure 11 Possible fragmentation patterns for 24-norursa-312-diene [2]

∙+

mz = 306 mz = 263

O

OH OH

OminusC3H7

+

Figure 12 Possible fragmentation patterns of incensole

MS and their mass spectrum showed a similar fragmentationpattern to ursane and oleanane type triterpenes having adouble bond at position 12 For both compounds the RDAreaction revealed a fragment ion signal at 119898119911 = 218 and afurther methyl cleavage from this fragment formed signal at119898119911 = 203 But the intensity of the fragment ion signal at119898119911 = 203 produced by 24-norursa-312-diene was foundto be greater almost by 50 than that produced by 24-noroleana-312-diene because the former is ursane derivativeof the latter As such the two nortriterpenes were identifiedPossible fragmentation pattern for 24-norursa-312-diene isgiven in Figure 11

The compound which produced molecular ion peaksignal at (M+)119898119911 = 306 in its mass spectrum correspondedto an elemental composition of C

20H34O2 Cleavage of the

isopropyl group from molecular ion at 119898119911 = 306 producedfragment with an elemental composition of C

17H27O2which

gave rise to peak at 119898119911 = 263 This diterpene is found to beincensole Possible fragmentation pattern for incensole wasgiven in Figure 12

Another compound identified in this study producedmolecular ion peaks signal at (M+) 119898119911 = 348 in its massspectrum that corresponded to an elemental composition ofC22H36O3 There are peaks that appeared in the mass spectra

at 245 288 and 305 Elimination of the isopropyl group frommolecular ion at 119898119911 = 348 produced fragment with anelemental composition of C

19H29O3which gave rise to peak

at 119898119911 = 305 whereas the fragment ion signal 119898119911 = 288is produced by cleavage of acetic acid group from molecularion (M+) Fragment ion peak signal at 119898119911 = 245 could beproduced by loss of an isopropyl group from 119898119911 = 288


OO

O

O

O

OO O

minusC3H7

minusC3H7

+

+

+

+

mz = 348mz = 305

mz = 288

mz = 245

minusCH3COOHminusCH3COOH

Figure 13 Possible fragmentation patterns for incensyl acetate [2]

This compound was identified as incensyl acetate Possiblefragmentation pattern for incensyl acetate was presented inFigure 13

Another pentacyclic triterpene identified from resin of Bpapyrifera producedmolecular ion peak signal at (M+)119898119911 =456 in its mass spectrum that corresponded to an elementalcomposition of C

30H48O3 When methyl group is lost from

molecular ion peak signal (119898119911 = 456) fragment with anelemental composition of C

29H45O3is produced which gave

rise to peak at 119898119911 = 441 The RDA reaction produced peaksignal at119898119911 = 218which produces peak signal at119898119911 = 203by loss of methyl group These fragmentations hold true forboth 120573-boswellic acid and 120572-boswellic acid However thefragment at 119898119911 = 203 was more abundant in the massspectrum of 120572-boswellic acid than 120573-boswellic acid due to themore stable ion formed from 120572-boswellic acid [2] Possiblefragmentation pattern for 120572-boswellic acid was presented inFigure 14

Another diterpene was also identified from methanolextract of B papyrifera by GC-MS The compound producedmolecular ion (M+) 119898119911 = 272 in its mass spectrumthat corresponded to an elemental composition of C

20H32

The fragmentation mechanism shows initially cleavage ofallyl methyl group from the molecular ion which furtherundergoes RDA reaction in the cyclohexene ring to producepeak signal at 119898119911 = 257 representing the base peak in itsmass spectra Accordingly possible fragmentation pattern forverticilla-4(20)711-triene was presented in Figure 15

34 Comparison of Chemical Compositions of the ThreeBoswellia Species As the concern of this study was com-parative chemical investigation on resins of three differentBoswellia species the essential oil and methanol extract ofB papyrifera B neglecta and B rivae resin were analysedby GC and GC-MS This led to the identification of thechemotaxonomical markers for each speciesThe GC investi-gations of the essential oils of B papyrifera B neglecta andB rivae resin showed that these oils were composed of anumber of monoterpenoic constituents But investigation onthe methanol extract of three Boswellia species showed thatthey are composed of diterpenes and triterpenes However

B papyriferawas identifiable by its diterpenoic and nortriter-penoic constituents

The essential oil of B papyrifera was found to bedominated by octyl acetate (571ndash657) followed by highcontent of n-octanol (34ndash88) linalool (10ndash21) andothersmonoterpenes In our previous study preliminary dataobtained by investigation on resin samples of three types ofBoswellia species collected from very limited area revealedsimilar results with the current study [13] In the presentstudy except for their composition similar constituentswere identified from the essential oils of the three Boswelliaspecies [13] Surprisingly similar components with identicalpercent composition were obtained for samples collectedfrom the same areas with samples collected for preliminaryinvestigation in our previous study The result obtained inthis study is also consistent with result obtained by otherauthors 646 according to Hamm et al [18] 636 byCamarda et al [20] and 56 by Dekebo et al [15] Assefaet al [21] also reported octyl acetate as major componentof B papyrifera In addition incensyl acetate was foundto be dominant component in methanol extract of resinsof B papyrifera B papyrifera was the only species thatwas found to contain octyl acetate n-octanol linalool andgeraniol and they are chemotaxonomical markers for thisspecies Octyl acetate and n-octanol were reported as theyare responsible for acrid odour of the resin [2] Oils fromboth B neglecta and B rivae were predominantly composedof 120572-pinene B neglecta was found to be rich in 120572-pinene(326ndash507) followed by terpinen-4-ol (175ndash299) and 120572-thujene (127ndash165) Similarly B rivaewas predominated by120572-pinene (325ndash662) followed by p-cymene (57ndash211) andlimonene (11ndash196)

The methanol extract of the Boswellia species resin sam-ples had considerable importance because the resin portion(di-and tri-terpenes) of frankincense is alcohol soluble Theboswellic acid was identified in frankincense samples aspentacyclic triterpenoic acids which follow the ursane andoleanane basic skeletonsThe presence of diterpenoic (incen-sole incensyl acetate and verticilla-4(20)711-triene) nor-triterpenes (24-noroleana-312-diene and 24-norursa-312-diene) and pentacyclic triterpene acid (120572-boswellic acid)constituents turned out to be a chemotaxonomical markerfor B papyrifera Methanol extract of B rivae and B neglectawas also found to containmonoterpene (120572-pinene) and triter-penes namely 120573-amyrin 120572-amyrin 120573-amyrenone and 120572-amyrenoneMost importantly twomonoterpenes (p-cymeneand 120572-thujene) were found to be characteristic for the Brivae and B neglecta Terpinen-4-ol and verbenone weretwo constituents identified as chemotaxonomical markersof essential oil of B neglecta whereas transverbenol and120572-campholene aldehyde are two monoterpenes which wereidentified only from essential oil of B rivae and hence arecharacteristic for this species

4 Conclusion

In this study essential oils and methanol extractof B papyrifera B neglecta and B rivae were investigated


H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+

Figure 14 Possible fragmentation patterns of 120572-boswellic acid

H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+

Figure 15 Possible fragmentation mechanism for verticilla-4(20)711-triene [2]

The investigations which were carried out by GC and GC-MSled to the identification of the chemotaxonomicalmarkers foreach species Some differences in their chemical constituentswere observed and are chemotaxonomical markers for eachspecies

The chemical investigations performed on threeBoswelliaspecies show that they consist of high number of monoter-penoic constituents and their methanol extract is composedof diterpenes and triterpenesThepresence of octyl acetate n-octanol and incensyl acetate provided an immediate recog-nition of B papyrifera from the other two species But still itis difficult to conclude that there is profound chemical qualityvariation between B papyrifera and the other two species(B neglecta and B rivae) that makes them not of exportstandard even though further study is required Howevera further investigation is crucial especially to extract somechemical information regarding the constituentswhichmightbe reasonable for their difference in color and physicalappearance

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to thank Center for InternationalForestry Research Ethiopia Office Addis Ababa the CentralLaboratory of the Haramaya University the Department ofChemistry of Addis Ababa University Department of Chem-istry of Indian Institute of Technology and the Ethiopian

Natural Gum and Marketing Enterprise for their collabora-tions during the research work that led to the productionof this paper Most of the expenses of this research workwere funded by the Austrian Development Agency throughCIFORrsquos Community Forestry Project in Ethiopia (Projectno 200803) The authors are thankful to the people andGovernment of Austria

References

[1] K Vollesen ldquoBurseraceaerdquo in Flora of Ethiopia I Edwards andS Hedbergand Eds vol 3 pp 442ndash447 National HerbariumAddis Ababa University Addis Ababa Ethiopia 1989

[2] S Basar Phytochemical investigations on Boswellia species [PhDthesis] University of Hamburg Hamburg Germany 2005

[3] A Al-Harrasi and S Al-Saidi ldquoPhytochemical analysis ofthe essential oil from botanically certified oleogum resin ofBoswellia sacra (Omani luban)rdquo Molecules vol 13 no 9 pp2181ndash2189 2008

[4] R A A Mothana S S Hasson W Schultze A Mowitzand U Lindequist ldquoPhytochemical composition and in vitroantimicrobial and antioxidant activities of essential oils of threeendemic Soqotraen Boswellia speciesrdquo Food Chemistry vol 126no 3 pp 1149ndash1154 2011

[5] H Safayhi E R Sailer and H P T Ammon ldquo5-Lipoxygenaseinhibition by acetyl-11-keto-120573-boswellic acid (AKBA) by a novelmechanismrdquo Phytomedicine vol 3 no 1 pp 71ndash72 1996

[6] S M AbdelWahab E A Aboutabl and SM El-Zalabani ldquoTheessential oil of olibanumrdquo PlantaMedica vol 53 no 4 pp 382ndash384 1987

[7] A Sharma S Chhikara S N Ghodekar et al ldquoPhytochemicaland pharmacological investigations on Boswellia serratardquo Phar-macognosy Reviews vol 3 no 5 pp 206ndash215 2009

[8] A O Tucker ldquoFrankincense and myrrhrdquo Economic Botany vol40 no 4 pp 425ndash433 1986

[9] J Stenhouse ldquoZusammensetzung des Elemi- undOlibanumolsrdquo Liebigs Annalen der Chemie vol 35 pp304ndash306 1840

[10] A Dekebo M Zewdu and E Dagne ldquoVolatile oils of frank-incense from Boswellia papyriferardquo Bulletin of the ChemicalSociety of Ethiopia vol 13 no 1 pp 93ndash96 1999

[11] Girmay Fitwi ldquoThe status of gum Arabic and Resins inEthiopiardquo Report of the Meeting of the Network for NaturalGumandResins inAfrica (NGARA)Network forNatural Gumand Resins in Africa Nairobi Kenya 2000

[12] Mulugeta Lemenih and Demel Teketay ldquoFrankincense andmyrrh resources of Ethiopia medicinal and industrial usesrdquoEthiopian Journal of Science vol 26 no 2 pp 161ndash172 2005

[13] M Assefa B Shimelis H Kassa et al ldquoChemical investigationson frankincense from Boswellia trees to improve produc-tion handling and grading practices for the export marketin Ethiopiardquo Global Journal of Pure amp Applied Science andTechnology vol 2 pp 15ndash30 2012

[14] J H Y Vilegas F M Lancas W Vilegas and G L PozettildquoFurther triterpenes steroids and furocoumarins from Brazil-ian medicinal plants of Dorstenia genus (Moraceae)rdquo Journal ofthe Brazilian Chemical Society vol 8 no 5 pp 529ndash535 1997

[15] A Dekebo E Dagne O R Gautun and A J Aasen ldquoTriter-penes from the resin of Boswellia neglectardquo Bulletin of theChemical Society of Ethiopia vol 16 no 1 pp 87ndash90 2002


[16] F A Badria B R Mikhaeil G T Maatooq andMM A AmerldquoImmunomodulatory triterpenoids from the oleogum resin ofBoswellia carterii birdwoodrdquo Zeitschrit fur Naturforschung Cvol 58 no 7-8 pp 505ndash516 2003

[17] C Mathe G Culioli P Archier and C Vieillescazes ldquoChar-acterization of archaeological frankincense by gaschromatography-mass spectrometryrdquo Journal of Chro-matography A vol 1023 no 2 pp 277ndash285 2004

[18] S Hamm J Bleton J Connan and A Tchapla ldquoA chemicalinvestigation by headspace SPME and GC-MS of volatile andsemi-volatile terpenes in various olibanum samplesrdquo Phyto-chemistry vol 66 no 12 pp 1499ndash1514 2005

[19] S G Leitao D R De Oliveira V Sulsen et al ldquoAnalysis of thechemical composition of the essential oils extracted fromLippialacunosa Mart amp Schauer and Lippia rotundifolia Cham (Ver-benaceae) by gas chromatography and gas chromatography-mass spectrometryrdquo Journal of the Brazilian Chemical Societyvol 19 no 7 pp S1ndashS28 2008

[20] L Camarda T Dayton V Di Stefano R Pitonzo and DSchillaci ldquoChemical composition and antimicrobial activityof some oleogum resin essential oils from Boswellia spp(Burseraceae)rdquo Annali di Chimica vol 97 no 9 pp 837ndash8442007

[21] M Assefa A Dekebo H Kassa A Habtu G Fitwi andM Redi-Abshiro ldquoBiophysical and chemical investigations offrankincense of Boswellia papyrifera from North and North-western Ethiopiardquo Journal of Chemical and PharmaceuticalResearch vol 4 no 2 pp 1074ndash1089 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


triterpenes exhibit very low volatility and polysaccharides arenot volatile [8]

Different commercial varieties of frankincense can bedistinguished by the chemical constituents of their essentialoil The constituents of the essential oil of frankincense werefirst investigated by Stenhouse [9] and he identified fourteenmonoterpenoic constituents Chemical investigation byBasar[2] on the essential oil of B neglecta and B rivae led toisolation and identification of monoterpenes The majorcompounds identified in B neglecta were 120572-thujene (213)120572-pinene (213) sabinene (13) Δ-3-carene (19) p-cymene (118) terpinen-4-ol (53) and verbenone (21)B rivae resin oil composition is quite similar to thatof B neglecta which consists of cara-24-diene (18) 120572-thujene (29) 120572-pinene (167) o-cymene (39) Δ-3-carene (173) p-cymene (32) and limonene (211) Inthe study triterpenoic constituents namely 120572-amyrin (91)120573-amyrin (07) epi-120572-amyrin (16) 120573-amyrenone (14)120572- and 120573-amyrin (3-12-dien-120572-amyrin (34) and 3-12-dien-120573-amyrin (11) were also identified from pyrolysateof B neglecta Similarly 24-norursa-312-diene (187) 120572-amyrin (42) 120573-amyrin (09) 120572-amyrenone (28) 120573-amyrenone (23) and epi-120573-amyrin (09) were detectedin the pyrolysate of B rivae Dekebo et al [10] reported theessential oil constituents of the resin of B papyrifera andidentified n-hexyl acetate (1) 120572-pinene (26) limonene(65) n-octanol (80) linalool (32) octyl acetate (56)caryophyllene oxide (21) and 120573-elemene (29)

Although Ethiopia is one of the few countries that areendowed with large frankincense resources little properexploitation of this resource has been made so far (iethe export market from Ethiopia has been weakened) dueto inconsistent supply and ambiguity of grades [11] Ofthe three Boswellia species found in Ethiopia frankincenseresin obtained from B papyrifera is the most widely tradedfrankincense accounting for over 90 of the natural gumexported The frankincense obtained from B rivae andB neglecta species is yet not of export standard [12] Asreported by Assefa et al [13] basis for selection of exportitem and the respective price quotations need to be revisedto reflect contents of ingredients sought after by buyersEthiopia will be more benefited from the export of theseitems provided efforts are made to develop these resourcesmore than the current situation However there is paucityof information on chemical quality variations between theexport standard frankincense (B papyrifera) and the othertwo Boswellia species (B rivae and B neglecta) which arenot of export standard This study is therefore initiatedfor comparative purpose where essential oil and methanolextract composition of one species were contrasted with theother(s) to characterize the chemical classes of constituentspresent and to find chemotaxonomical markers among theseconstituents for the three Boswellia species

2 Materials and Methods

21 Description of Sampling Sites and Sample Collection Theresin samples of frankincense (Boswellia species) used for this

study were collected in August 2011 from northwestern andsoutheastern Ethiopia From northwestern Ethiopia threesites were selected Metema from Amhara region Humerafrom Tigray regional state and Metekel from BenishangulGumuz regional state From these sites exudates were col-lected from B papyrifera Samples from southeastern partof the country were collected from three districts namelyMega Dubuluk and Wachile from Borana zone of Oromiyaregion In these entire three sites one dominant speciesknown as B neglecta is widely grown Then samples werealso collected from Filtu Chereti and Dolo Odo districts ofSomalia regional state In these sites B rivae was dominantThe studied samples were an authentic sample which arecertified for their authenticity by Agricultural Departmentof the Ethiopian Government Natural Gum Processing andMarketing Enterprise The geographical locations of thedistricts are given in Table 1

22 Chemicals and Reagents All chemicals and reagents usedwere of analytical grade Chloroform (999) and methanol(998) were purchased fromMerck (Darmstadt Germany)Anhydrous sodium sulfate was purchased fromFluka (BuchsSwitzerland)

23 Equipment and Instruments Polyethylene plastic bagsceramic mortar and pestle (Haldenwanger Germany)a digital analytical balance (Mettler Toledo Model AG204 Switzerland) round bottom flask (Mumbai India)Clevenger apparatus (Rac India) rotary evaporator andheating mantle (Buchi Switzerland) Gas chromatography(Monza Italy) Gas chromatography-mass spectrometry(PerkinElmer USA) and syringes (Hamilton Bonaduz AGSwitzerland) are among the equipment and instruments thatwere used in the study

24 Methanol Extraction and Isolation of Essential Oils Theresins of the three Boswellia species were air-dried at roomtemperature for 4 weeks grinded and homogenized to auniform powder by ceramic mortar and pestle and sievedTwo grams of grinded and homogenized resins powder wasextracted with 30mL of methanol at room temperature Theextracts were concentrated using a rotary evaporator andanalyzed by GC-MS For essential oils the ground resins ofthe three Boswellia species B papyrifera B neglecta andB rivae were submitted for 3 h to hydrodistillation using aClevenger-type apparatus The obtained oils were allowed todry over anhydrous sodium sulphate After filtration the oilswere stored at +4∘C until analyzed [4]

25 Gas Chromatography GC analyses were performedon Dani model 1000 Gas chromatography (Monza Italy)equipped with flame ionization detector (FID) The analysiswas carried out on a fused silica capillary column coated withHP-5 column length 30m internal diameter 032mm filmthickness 025 micron and 5 phenyl 95 methyl polysilox-ane as stationary phase The oven was programmed at 50ndash210∘C at a rate of 3∘Cmin using N

2as carrier gas injector

and detector (FID) temperatures were 210∘C and 260∘C






EasternFiltu 5∘051015840353510158401015840 N 40∘391015840309910158401015840 E







119877) on




5 6 7 8 9 10 11 12 13 14 15 16

00

02

04

06

Inte

nsity

(au

)


WachileMega

Dubuluk


6 7 8 9 10 11 12 13 14

00

01

02

03

04In

tens

ity (a

u)







6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

000

005

010

015

020

025

Inte

nsity

(au

)


MetemaMetekelHumera









100

0

()

600 1100 1600 2100 2600 3100 3600Time

633

2888 3678

3820

3893


638

2799

37473813

3888

100

0

()

600 1100 1600 2100 2600 3100 3600Time





100

()

2087

2483

2495

2625

2703

300 700 1100 1500 1900 2300 2700 3100Time

0


100

0

()

600 1100 1600 2100 2600 3100 3600Time

2041

2187

2178

30473128

3718



100

()

300 700 1100 1500 1900 2300 2700 3100Time

01954

2090

2644

2953






30H48O However the




HH

OH

HOminusCH3

mz = 409mz = 424

RDA

mz = 218

minusCH3

mz = 203

minusCH2CH3

mz = 189

Omz = 205

∙+

CH2


mz = 426

mz = 411

mz = 218

mz = 203

mz = 189

mz = 393

mz = 207

mz = 409

H

H

H

H

minusCH3

minusCH3

minusOH

minusH2O

OH

OH

CH2

RDA

∙+






mz = 394

mz = 218

mz = 203

mz = 175

mz = 161

minusCH3

minusCH3

H

H

H

+∙

+


∙+

mz = 306 mz = 263

O

OH OH

OminusC3H7

+






17H27O2which







OO

O

O

O

OO O

minusC3H7

minusC3H7

+

+

+

+

mz = 348mz = 305

mz = 288

mz = 245










20H32






4 Conclusion



H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+


H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+






Acknowledgments



References
































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






EasternFiltu 5∘051015840353510158401015840 N 40∘391015840309910158401015840 E







119877) on




5 6 7 8 9 10 11 12 13 14 15 16

00

02

04

06

Inte

nsity

(au

)


WachileMega

Dubuluk


6 7 8 9 10 11 12 13 14

00

01

02

03

04In

tens

ity (a

u)







6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

000

005

010

015

020

025

Inte

nsity

(au

)


MetemaMetekelHumera









100

0

()

600 1100 1600 2100 2600 3100 3600Time

633

2888 3678

3820

3893


638

2799

37473813

3888

100

0

()

600 1100 1600 2100 2600 3100 3600Time





100

()

2087

2483

2495

2625

2703

300 700 1100 1500 1900 2300 2700 3100Time

0


100

0

()

600 1100 1600 2100 2600 3100 3600Time

2041

2187

2178

30473128

3718



100

()

300 700 1100 1500 1900 2300 2700 3100Time

01954

2090

2644

2953






30H48O However the




HH

OH

HOminusCH3

mz = 409mz = 424

RDA

mz = 218

minusCH3

mz = 203

minusCH2CH3

mz = 189

Omz = 205

∙+

CH2


mz = 426

mz = 411

mz = 218

mz = 203

mz = 189

mz = 393

mz = 207

mz = 409

H

H

H

H

minusCH3

minusCH3

minusOH

minusH2O

OH

OH

CH2

RDA

∙+






mz = 394

mz = 218

mz = 203

mz = 175

mz = 161

minusCH3

minusCH3

H

H

H

+∙

+


∙+

mz = 306 mz = 263

O

OH OH

OminusC3H7

+






17H27O2which







OO

O

O

O

OO O

minusC3H7

minusC3H7

+

+

+

+

mz = 348mz = 305

mz = 288

mz = 245










20H32






4 Conclusion



H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+


H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+






Acknowledgments



References
































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

000

005

010

015

020

025

Inte

nsity

(au

)


MetemaMetekelHumera









100

0

()

600 1100 1600 2100 2600 3100 3600Time

633

2888 3678

3820

3893


638

2799

37473813

3888

100

0

()

600 1100 1600 2100 2600 3100 3600Time





100

()

2087

2483

2495

2625

2703

300 700 1100 1500 1900 2300 2700 3100Time

0


100

0

()

600 1100 1600 2100 2600 3100 3600Time

2041

2187

2178

30473128

3718



100

()

300 700 1100 1500 1900 2300 2700 3100Time

01954

2090

2644

2953






30H48O However the




HH

OH

HOminusCH3

mz = 409mz = 424

RDA

mz = 218

minusCH3

mz = 203

minusCH2CH3

mz = 189

Omz = 205

∙+

CH2


mz = 426

mz = 411

mz = 218

mz = 203

mz = 189

mz = 393

mz = 207

mz = 409

H

H

H

H

minusCH3

minusCH3

minusOH

minusH2O

OH

OH

CH2

RDA

∙+






mz = 394

mz = 218

mz = 203

mz = 175

mz = 161

minusCH3

minusCH3

H

H

H

+∙

+


∙+

mz = 306 mz = 263

O

OH OH

OminusC3H7

+






17H27O2which







OO

O

O

O

OO O

minusC3H7

minusC3H7

+

+

+

+

mz = 348mz = 305

mz = 288

mz = 245










20H32






4 Conclusion



H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+


H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+






Acknowledgments



References
































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


100

()

2087

2483

2495

2625

2703

300 700 1100 1500 1900 2300 2700 3100Time

0


100

0

()

600 1100 1600 2100 2600 3100 3600Time

2041

2187

2178

30473128

3718



100

()

300 700 1100 1500 1900 2300 2700 3100Time

01954

2090

2644

2953






30H48O However the




HH

OH

HOminusCH3

mz = 409mz = 424

RDA

mz = 218

minusCH3

mz = 203

minusCH2CH3

mz = 189

Omz = 205

∙+

CH2


mz = 426

mz = 411

mz = 218

mz = 203

mz = 189

mz = 393

mz = 207

mz = 409

H

H

H

H

minusCH3

minusCH3

minusOH

minusH2O

OH

OH

CH2

RDA

∙+






mz = 394

mz = 218

mz = 203

mz = 175

mz = 161

minusCH3

minusCH3

H

H

H

+∙

+


∙+

mz = 306 mz = 263

O

OH OH

OminusC3H7

+






17H27O2which







OO

O

O

O

OO O

minusC3H7

minusC3H7

+

+

+

+

mz = 348mz = 305

mz = 288

mz = 245










20H32






4 Conclusion



H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+


H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+






Acknowledgments



References
































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


HH

OH

HOminusCH3

mz = 409mz = 424

RDA

mz = 218

minusCH3

mz = 203

minusCH2CH3

mz = 189

Omz = 205

∙+

CH2


mz = 426

mz = 411

mz = 218

mz = 203

mz = 189

mz = 393

mz = 207

mz = 409

H

H

H

H

minusCH3

minusCH3

minusOH

minusH2O

OH

OH

CH2

RDA

∙+






mz = 394

mz = 218

mz = 203

mz = 175

mz = 161

minusCH3

minusCH3

H

H

H

+∙

+


∙+

mz = 306 mz = 263

O

OH OH

OminusC3H7

+






17H27O2which







OO

O

O

O

OO O

minusC3H7

minusC3H7

+

+

+

+

mz = 348mz = 305

mz = 288

mz = 245










20H32






4 Conclusion



H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+


H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+






Acknowledgments



References
































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


OO

O

O

O

OO O

minusC3H7

minusC3H7

+

+

+

+

mz = 348mz = 305

mz = 288

mz = 245










20H32






4 Conclusion



H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+


H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+






Acknowledgments



References
































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


H

H

HRDA

∙

minusCH3

minusCH3

mz = 441

mz = 203

mz = 456

mz = 218

HOOCHO

+


H H

RDAminusCH3

minusCH3

mz = 272 mz = 257mz = 257

+

∙+






Acknowledgments



References
































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Boswellia B. papyrifera (Del.) Hochst., B. neglecta S. B ...4 ISRNAnalyticalChemistry 6 7 8 9 10 11...

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Transcript of Boswellia B. papyrifera (Del.) Hochst., B. neglecta S. B ...4 ISRNAnalyticalChemistry 6 7 8 9 10 11...