PertanikaJ. Sci. & Techno!. 6(2): 171 - 182 (1998)ISSN: 0128-7680

© Universiti Putra Malaysia Press

Wax Lipids from Leaf Surfaces of SomeCommon plants of Malaysia

M. Radzi bin Abas l and Bernd R.T. SimoneieIDepartrnent of Chemistry, Universiti Malaya,

50603 Kuala Lumpur, Malaysia.

2Petroleum and Environmental Geochemistry Group,College of Oceanic and Atmospheric Sciences,

Oregon State University,Corvallis, OR 97331, U.S.A.

Received: 10 November 1997

ABSTRAKEkstrak lipid lilin epikutikular daripada daun-daun beberapa jenis tumbuhanyang terdapat di Lembah Klang telah di asingkan kepada pecahan-pecahanhidrokarbon, asid karboksilik, keton dan alkohol. dan seterusnya dianalisisdengan menggunakan kaedah kromatografi gas (KG) dan kromatografi gasspektrometri jisim (KG-5J). Mesau fem!a menghasilkan amaun lilin terbanyak,semen tara yang paling sedikit diperolehi daripada Eugenia gral1dis. Dalamkebanyakan spesies yang dikaji, n-alkana utama yang ditemui ialahhentriakontana (C

31), diikuti oleh triakontana (C,,) dan nonakosana (C",,). n­

Alkana mempamerkan pola mata-gergaji, iaitu merupakan satu ciri hidrokarbondari sumber biogenik, sementara asid n-alkanoik dan n-alkanol pulamempamerkan satu corak di mana bilangan karbon genap lebih ketara daripadabilangan karbon ganjil. j)-5itosterol merupakan fitosterol utama yang dikesan didalam sesetengah spesies, tetapi dalam kuantiti surihan sahaja. Tritel-penoiddan triterpena kebanyakannya ditemui di dalam Jilin spesies MeS1lo fen'eo dimana asid (1.- dan p-boswelik merupakan komponen mama, dan (1.- danj)-amyrin dengan amaun yang minor. Biopenunjuk lain yang dikesan termasuklah(1.- dan j)-amyron, friedelin, friedelanol, friedelana, 0Iean-12-ena, tarakserena,skualena, asid dihidroniktantik, asid dihidroburik dan asid dihidrokanarik.Kajian ini menunjukkan bahawa taburan n-alkana merupakan fungsi suhupersekitaran setempat.

ABSTRACT

Epicuticular wax lipids from leaves of some common plant species found inthe Klang Valley, Malaysia were extracted into dichloromethane for analysis.Extracts were separated into hydrocarbon, carboxylic acid, ketone and alcoholfractions. The fractions after derivatization were then subjected to gaschromatographic (GC) and gas chromatography-mass spectrometric (GC-M5)analyses. The wax yield was highest for Mestta fen'ea while the lowest yield wasobtained from Eugenia gran dis. In most species studied the m~or n-alkanewas found to be hentriacontane (C31 ), followed by tritriacontane (C,,) andnonacosane (C",) , respectively. The n-alkanes exhibit a saw-tooth patternwhich is characteristic of a biogenic origin. A strong even-to-odd carbonnumber predominance is observed for both the n-alkanoic acids and 1)­

alkanols. Only traces of mainly p-sitosterol were detected in some of the

M. Radzi bin Abas and Bernd RT. Simoneit

species. The triterpenoids and triterpenes were mostly found in the wax ofMesua ferrea with «- and p-boswellic acids as the major components andminor amounts of «- and p-amyrin. Other biomarkers identified were «­and p-amyrones, friedelin, friedelanol, friedelane, olean-12-ene, taraxerene,squalene, dihydronyctanthic acid, dihydroroburic acid and dihydrocanaricacid. This study has shown that the distribution of n-alkanes is a functionof the ambient temperature.

KeyWords: epicuticular wax, organic chemical analysis, Ge, GC-MS

INTRODUCTION

The leaf surfaces of vascular plants generally consist of a lipophilic polymermembrane (cuticle) whose monomers are mostly hydroxy fatty acids(Kolattukudy, 1970, 1980; Martin and Juniper, 1970). Growing from thecuticular membrane are complex mixtures of lipids, often in crystalline form,called epicuticular plant waxes. These waxes act as a protective barrier betweencuticula and the atmosphere (Eglinton et at. 1962a; Hall and Jones, 1961;Jameison and Reid, 1972; Kolattukudy, 1970, 1976; Martin and Juniper, 1970;Rogge et at. 1993a; Schreiber and Schonherr, 1992) and also to prevent losts ofwater, ions, etc. from the leaves.

Epicuticular plant waxes consist mainly of aliphatic compounds such ashigher molecular weight (usually >C24 ) n-alkanes, n-alkanals, n-alkanols, n­

alkanoic acids, and wax esters (Eglin ton et at. 1962a; Kolattukudy, 1970,1976; Simoneit and Mazurek, 1982; Simoneit, 1989). Due to wind-inducedmechanical shear, rubbing of leaves against each other and rainfall, suchepicuticular wax protrusions become airborne. In some areas, the leafmaterial produced during an annual growing cycle is deposited in nearbygardens and along streets. In this manner, leaf waxes may be added togarden soil and to road dust. Wind- or traffic-induced turbulence canresuspend garden soil and road dust, thus entraining particles of vegetativedetritus into the atmosphere. Therefore, it is not uncommon to find theoccurrence of plant wax constituents in airborne particulate matter in bothurban and rural aerosols (Doskey and Andren, 1986; Gagosian et at. 1982;Mazurek et at. 1991; Rogge et at. 1993b; Sicre et at. 1990; Simoneit, 1979,1989; Simoneit and Mazurek, 1982; Simoneit et at. 1988, 1990, 1991 b; Wilset at. 1982). So any study on the organic composition of atmosphericaerosols will require knowledge of the natural background signal fromindigenous vegetation.

Many compositions of plant waxes from individual species have beenreported in order to utilize the data for chemotaxanomic correlations (e.g.Eglinton et at. 1962a,b; Eglinton and Hamilton, 1963; Borges del Castillo et at.1967; Herbin and Robins, 1968a,b; Martin-Smith et at. 1967; Nishimoto, 1974;Salasoo, 1987; Stransko (y, ') et at. 1967; Tulloch, 1976; Wollrab, 1967; Zygaldoet at. 1994). However, the plant wax composition found in aerosols is anadmixture, generally representative of the plant species in the air shed

172 PertanikaJ. Sci. & Techno!. Vo!' 6 No.2, 1998

Wax Lipids from Leaf Surfaces of Some Common plants of Malaysia

(Simoneit, 1977. 1989; Simoneit and Mazurek, 1982). Thus it is more usefulto consider vegetation species which are representative of a particular studyarea for wax analysis, in order to use the results for aerosol sourcereconciliations.

This paper describes the composition of the solvent extractable organicmatter obtained from leaf surfaces of ten plant species commonly found in andaround the city of Kuala Lumpur, Malaysia. It is hoped that this study willenable us to identify some suitable marker compounds or marker compoundassemblages for tracing vegetative detritus particularly in the aunosphere ofKuala Lumpur.

EXPERIMENTAL

Ten plant species were chosen for this study based on their high abundancein and around the city of Kuala Lumpur. The plants were sampled mostlyon the campus of the Universiti Malaya. The species chosen were: Calophylluminophyllum Linn. (Guttiferae); Cerbera odollarn Gaertn. (Apocynaceae); Eugeniagran.dis Wight (Myrtaceae); Fagraea Jragrans Roxb. (Loganiaceae); Heveabrasiliensis M.A. (Euphorbiaceae); Melaleuca leucadendron Linn. (Myrtaceae);Mirnusops elengi Linn. (Sapotaceae); Mesua Jerrea Linn. (Guttiferae);Lagerstroemia indica Linn. (Lythraceae); and Pterocarpus in.dicus Willd.(Leguminoseae). Descriptions of these species can be found in Burkill(1935).

Sampw ExtractionA representative sample of between 20-45 mature leaves of uniform size andappearance was taken from at least five individual plants of a particular speciesand combined. Care was taken to exclude any insects from the leaves. Theleaves were placed in a paper bag before being u'ansported to the laboratory.In the laboratory, each leaf was dipped (up to the stem) for 3-5 seconds intoabout 150 ml of distilled-in-glass methylene chloride. All leaves were handledwith forceps. The extracted leaves were dried and weighed. The excess solventwas removed by rotary evaporation and nitrogen blowdown to 1-2 ml. Eachconcentrated extract was transferred to a vial with Teflon lined cap and keptrefrigerated until further analysis.

Lipid Separation and AnalysisThe concentrated extracts were reacted with BF

3-methanol to esterify carboxylic

acids and separated into hydrocarbon, ester, ketone (and aldehyde) andalcohol fractions by thin layer chromatography on silica gel plates. Thesefractions were then subjected to gas chromatographic (GC) and gaschromatography-mass spectrometric (GC-MS) analyses. Alcohol fractionswere converted to the trimethylsilyl ethers prior to GC and GC-MS analysis byreaction with N, D-bis-(timethylsilyl)-trifluoroacetamide(BSTFA). Perdeutero­n-dotriacontane was used as a coinjection standard. A more detailed description

Pertanika.J. Sci. & Technol. Vol. 6 No.2, 1998 173

M. Radzi bin Abas and Bernd RT. Simoneil

of the complete experimental format has been described elsewhere (Abas el at.1995). The GC analyses used a capillary column coated with DB-l (30 m 30.25 mm i.d.) and the operating conditions, for the analyses of fraction 1only, were as follows: isothermal at 65"C for 2 min, temperature program 65­180"C at 25"C per minute and 180-310nC at 4"C per minute, then holdisothermal at 310"C for 60 min. A slightly slower temperature programme (65to 310"C at 4"C/min) was used for the other fractions.

The GC-MS analyses were conducted on a Finnigan Model 4021 quadrupolemass spectrometer interfaced directly with a Finnigan Model 9610 gaschromatograph equipped with the same column as for the GC analyses. TheGC used the same operating conditions as above and the MS scanned for50-650 da at 2 sec/decade with an electron impact ionization potential of 70 eY.Mass spectrometric data were acquired and processed with the Finnigan-Incosdata system. In GC-MS analyses the homologous compound series are definedby key ion mass chromatograms. Thus, the n-alkanes are characterized in m/z 99 [ragmentograms, the n-alkanoic acids as the methyl esters in m/z 74 or 87[ragmentograms, the n.-alkanols as the trimethylsilyl ethers in m/z 75[ragmentograms and by their M-15 ions, and the n-alkanals and lI-alkan-2-onesin m/z 71 and m/z 58 [ragmentograms, respectively. Alkyl diesters of benzene­1,2-dicarboxylic acid (phthalates) are identified by m/z 149 and m/z 163[ragmen tograms.

RESULTS AND DISCUSSION

The extract yields and lipid characteristics of the plant waxes [rom the speciesstudied are given in Table 1. The wax yield was highest for Mesua Jerrea whilethe lowest yield was obtained from Eugen.ia grandis. Because of the similarity ofthe compound series amongst the species, only a selected number of sampleswas examined further by GC-MS. The carbon number maxima (Cm"J, carbonnumber range and carbon preference indices (CPI) for the on-alkanes, 17­

alkanoic acids and n-alkanols are also listed in Table 1.

Aliphatic HydrocarbonsThe n-alkanes were identified in fraction 1 of the separated wax extracts andare listed in Table 2. The n-alkanes of biosynthesized leaf wax exhibit a strongodd-to-even carbon number predominance with the dominant n-alkanes beingC~~" C31 , and C33 (Eglin ton et at. 1962b; Kolauukudy, 1970; Rieley el al. 1991;Simoneit and Mazurek, 1982). This is also evident in our study where weidentified on-alkanes ranging [rom C1!1 to C31i, having the odd-carbon II-alkanesexceeding their even-carbon neighbors, thus exhibiting a saw-tooth patternwhich is characteristic of biogenic n-alkanes. In most species the major alkane(Cm"x' Mazurek and Simoneit, 1984) was henu"iacontane (C31 ), followed bytritriacontane (C33) and nonacosane (C2!I), respectively. It was also noted thattriacontane (C

30) was present as an important component in Fagraea Jragrans.

The CmoLx

[or the n-alkanes of vascular plant wax samples from Amazonia,

174 PertanikaJ Sci. & Techno!. Va!. 6 TO. 2, 1998

TABLE IExlracl yields and lipid characleristics of epiculicular plant waxes invesligaled

n-Alkanes n-Alkanoc acids n-Alkanols

EXlract FractionCode l'ield rielel of total C t CP' C t Range CPr' C t Range Cpp

Plant Species] Ill;IX 1ll;1'( lII:l'll:

(mg/g dry wt.) (mg/g) wax(%)=i2.,x

Calophyllum inophyllum Cn 6.4 2.0 32 29,31 13.3 lQ,24,26 16-23 13.5 ]O,lQ 10-20 00 C(All Heal Tree, Penaga -0

~Laut) V>

"0 Cerbera odollum Co ]8.2 4.6 25 11,33,35 13.5 16,32,34 14-36 35.5 34 24-36 18.3 =i'" a.,0;- (Yellow-eyed Carbera, 33. Pong-Pong) r',.,. ".,

Eugenia grandis Eg 1.2 0.4 33 11 14.5 16,32,34 ]2-34 5.9 32 24-34 12.2.,

,..... ...,C/l

C/l (Sea Apple, Jambu Lalli) :::('l .,

Fagraea fragrans Ff 7.2 0.6 8 29,30,11 3.6 24,26,28 ]6-34 12.2 ]0,28 10-34 6.2 ;l'?!> ('l

(Common Tembusu, "..., V>

" Tembusu) a('l ...,",. Hevea brasiliences Hb 4.3 0.7 15 11,33 7.2 20,24 14-24 40.7 18 18-20 00 C/l

~a

(Para Rubber Tree, 3-< Getah Para) "a ('):- Lagerstroemia indica Li 2.8 0.3 11 11 6.5 16,20,26 ]2-36 14.8 26,28 22-36 8.5 aC>

(Crepe M)'rLle, Bungor) 3Z 3? Mimusops elengi Me 2.0 1.6 79 31,33 18.1 16,28,30 14-34 26.6 28,30 18-36 [4.4 a-"" (Tanjung Tree,

:l

- -0<0 Pokok Tanjung) ;J<0 :lex> Mesua ferrea Mf 35.4 0.04 2 29,31 9.6 16,18 14-32 37.2 30,32 24-34 5.3 v;

(Indian Rose Chestnut, a...,Penaga Lilin) ~

Melaleuca leucadendron MI 5.6 0.04 0.6 31 3.0 n,28,30 14-32 7.3 28,30 24-34 5.3.,;J

(Capepul, Gelam) ~

Plerocarpusindicus Pi 5.0 1.7 33 29,31,33 25.2 16,26 14-34 97.5 26,28 22-36 30.[;;'

(Red Sandalwood.Angsana)

...., I Lalin name, in parentheses English common name, Malal'sian vernacular name.U'. 2 Cm", = carbon number maximum as defined in Mazurek and Simoneil (1984) .

~ CPI = Carbon preference index is the sUlllmation of 111(' odd carbon number hOlllologs divided hy rhe summation af Ihe even carbon number hamalags farII-alkanes and Ihe inverse for 1/-alkanoic acids and /~alkanols (Mazurek and Simoneil, 1984).

TABU: '2

- Major II-alkanes and biomarkers in the epiCllticular plant waxes analyzed froll1 Malaysia-.)Ol

Compound Plant Species

Name Composition Cn Co Eg Ff lIb Li Me Mf MI Pi

Il-Alkanes (, dative concentration")Docosane CnH,r. 0.6 0.4Tricosane C"H'8 0.7 1.2 I I 2 0.4Tetracosane C21 H"" 0.5 I 2 I 0.2 2 8 0.4

'"0 Pentacosane C"H" 0.9 2 2 3 0.4 2 12 1.5 ;s:".., Hexacosane C2foH" 0.8 I 2 2 0.4 2 15 0.5

~0;:l Heptacosane

C'7H

""3 0.5 14 3 6 2.6 3 22 4.2 0-

~ Octacosane C.sK" 3 0.5 7 2 3 0.5 2 19 0.7 ~.

'":- Nonacosanc C,.H", 100 5 16 78 9 36 15 32 41 33 ~Vl Tiacontane C",Hr., 7 I 3 37 4 10 2 6 II 2

:l!:l. >Ro Hentriaconl<1ne C."H", 90 61 100 100 100 100 81 100 100 100 U"- '"~ Dotriaconlane C"H,,, 3 10 5 9 16 13 7 3 9 3 '"

'"" Tritriacontanc C"H,,, 8 100 17 7 96 21 100 11 J9 31 ::ln=- 0-

'" Tetrnlriacontanc C"H70 3 4 I 0.2~ Pentatriacontane C"H" 19 13 2 0.7

1:0"-< Hexalriacontane C,,;H71 I..,'"0 0-:- Heptatriacontane C37Hili 2 3

C> ~

Z ;..,!' Biomarkers (hl'drocarbons relative to n-alkanes, oxygenated relative presence) Vl.~ a-Amrrin C",H""O + ++ ++ ~3'- B-Am}'rin C",K",O + +++ +++ 0<0 '"<0 a-Boswellic acid C",H"O, ++++, £.co

B-Boswellir acid C",H"O, ++++-+a- & B-AIll}'rones C",H'80 +++ ++ ++-+FriedelinC30mOO C",H."O + +++ + ++ ++Friedelanol C",K"O + +++Friedclanc C..,H." 7Olean- 12 - cne C",H:" I 4 15Taraxcn;llc C",H." 1.4 19 40Dih}'dron}'ctanthic acid C",H."O, + +Dih}'drorobul ir acid C",H."O, ,

~

Dih}'dJ ocanaric acid C",H:"O, + t +Squalene C",H:" 3

'Colllpound wilh fhe highesL concentration is assigned a value of 100

Wax Lipids from Leaf Surfaces of Some Common plants of Malaysia

Australia, Punta Arenas (S. America), igeria and the United States arc allgenerally at C

2Y(Table 3). Thus the higher Cm", of these samples reflects the

higher ambient temperature which results in biosynthesis of longer carbonchain lipids which have higher melting points (Simoneit, 1977).

Since biosynthetic n-alkanes exhibit a strong odd-carbon numberpredominance, the concenu"ation ratio of odd-to-even number homologues(carbon preference index, CPI, Mazurek and Simoneit, ] 984) of plant wax /1­

alkanes will have values of >1. The CPI values of the n-alkane homologuesobtained in this study range from 3.0-25.2. These values are comparable to theCPI values reponed for other studies (Table 3).

n-Alkanoic alld n-Alkenoic AcidsAnother major compound class commonly identified in epicuticular plantwaxes is the group of long-chained saturated n-fatty acids (Kolattukudy, ]970;Simoneit, 1977, ]989; Simoneit and Mazurek, ]982; Rieley et ai. 1991). In thisstudy, the 'n-alkanoic acids are found in both fractions 2 and 3 of the extracts,The n-alkanoic acids show a strong even-to-odd carbon number predominancewith Cm", at Clli and C20' C24 ' C28 or C32. Of all the species investigated five speciesexhibit Cm", at C\li and two have Cm", at C28' with the remainder at other carbonnumbers (Table]). The CPIc,",'" values range from 5.9 to 97.5. For comparison,the CPI',""ll values reponed for other studies range from ]3.1 to 34.0 (Table 3).

Unsaturated n-fatty acids have also been identified and quantified in theleafwax eXU"acts. Oleic (C IS:I )' linolenic (CI8:2), and linoleic (C I8::) acids are themajor unsaturated n-fattyacids (n-alkenoic acids) identified here, however. theyoccur as trace components.

n-Alkanols and n-AlkanafsBoth n-alkanols and II-alkanals are synthesized enzymatically by plants fromprecursor n-alkanoic acids (Kolattukudy, 1970). The long-chain primary 11­

alkanols with even carbon number predominances and Cm.1X

at C2li

' C28

' Cw Gl2

or C34

have been identified in the present study. They range from CIIJ to G'li

with CPIcvell values from 5.3 to 00 (Table 1). These values are in the same rangeas reported for other areas (Table 3). The n-alkanals are not as common inthese samples. Only two samples had long chain alkanals as minor components(·r the wax.

Molecular Markers (Biomarkers)Biogenic molecular markers (i.e. biomarkers) include the triterpenes andterpenoids or their derivatives such as phytosterols, triterpenols and triterpenolacids, sesquiterpenoids and diterpenoids.

(a) Ph)'tosferofsIn this study, the phytosterols are found in the alcohol fractions of the plantwax exu"acts, but only U"aces of mainly b-sitosterol were detected in some of thesamples. Phytosterols are not major components of wax from u'opical vegetation.

PertanikaJ Sci. & Technol. Vol. 6 0.2,1998 177

- TABLE 3....00

A comparison of lipid characteristics of vascular palant wax from various global locations.

n-Alkanes n-Alkanoc acids n-Alkanols

Latitude Mean ambient Total Yield CPI Qlla=< Yield CPI Ollil); Yield CPI OIl,Ur,

(approx.) temperature extract ( gig) ( gig) ( gig) Ref.Locations (0C) (mg/g)

"1:1 Malaysia 3°N 28 1.2-35.4 40-4600 3.0-25.5 29,QJ.,33 n.a. 5.9-97.5 16,14,28, n.a. 5.3- 16,18,26, Present study ~n32 28,30,32,..,

i:?0;34:l 0-

~ t:!.

'" 0-:- Australia 34°S 22 80 1400 16.0 29 2650 17.1 16.25 80000 47.5 26 Simoneit el al. 5'en (199Ib)CJ. >-0-

R" '"'"..., Brazil 3°C 30 n.a. n.a. 14.1 29 n.a 25.0 16,22 n.a. 8.5 30 Simoneits el. al.'"n

(1990) ::lt'l (Amazonia)::r 0-:l

tl:l~ Chile 54°S 10 630 mg 12 ng/g 30 29 34.0 16,26 10.0 gg,24 Simoneits el. al.n

2: n.a. n.a. ..,:l(Punta Arenas) (1991a) 0-

0'> :>:lZ Nigeria 9°N 24 300 28.4 29 200 13.1 16,20,24 240 14.6 30 Simoneits el. al.

;...,9 n.a.

en-"" 30 (1988) 3'- 0<.0

U.S.A 39°N 20 6 184 59 320 18.2:l

<.0 29 12,24,30 1680 18.4 16,24,30 Simoneits and ~.00(California) Mazurek (1882)

Japan 34"N 16 n.a. 100-3800 n.a. 29,31 n.a. n.a. n.a. n.a. n.a. n.a. Nishimoto (1974)

UAS. 45"N 18 n.a. n.a. 3.6-17 23-33 n.a. 2.3- 16-28 n.a. 3-11 22-28 Standley (1988) ;Chen(Oregon) (1992)

n.a. = not analyzed

Wax Lipids from Leaf Surfaces of Some Common plants of ~Iala}'sia

(b) TriterpenoidsThe alcohol fraction of M. ferrea wax contains a-boswellic and b-boswellic acidsas major components, with minor amounts of a-amyrin and b-am)'l'in (Table 2).The mass specu'um of methyl b-boswellate trimethylsilyl ether (G14H:,~O:\Si,

methyl 0Iean-12-en-3a-ol-24-oate-3-trimethylsilyl ether) exhibits a molecular ion,M-CH

3, M-CH

30H

2and the characteristic key ions of the oleanene rings C-E at

m/z 203 and 218. Both a-amyrin and b-am)'l'in are lesser constituents in theother samples (Table 2). The other triterpenoids found are also listed in Table2. Friedelin and friedelanol are significant components of E. gmndis and H.brasiliensis wax, respectively. M. ferrea wax contains various triterpenes such asthe amyrins and minor oxidation and/or alteration products, such as amyrones,seeo-amyrins (i.e. dihydroroburic and dihydronyctanthic acids) and seco-lupeol(i.e. dihydrocanaric acid). These latter compounds are also recognizable asminor components in some of the other waxes where the parent compoundsare present. The mass spectra of these seeD compounds are mainly the dihydroderivatives. Photo-oxidation of the precursors should initially yield theintermediates such as roburic, nyctanthic and canaric acids, however, thedihydro acids have been reported to form directly by photochemical cleavageof amyrones (Arigoni et al. 1960). Methyl dihydronyctanthate exhibits a smallmolecular ion and M-15 with the characteristic key ions of the oleanene ringsC-E at m/z 203 and 218. The GC elution order is as for the amyrins, i.e.dihydronyctanthic acid before dihydroroburic acid.

(c) Sesqui- and DilerpenoidsNo sesquiterpenoids nor diterpenoids were detected in the wax exu'acts ofthese samples.

PhthalalesThe presence of dialkyl esters of benzene-l,2-dicarboxylic acid (phthalates) issignificant (e.g. in fraction 4 of E. grandis and L. indica). These compounds arenot known to be present in waxes of plants, but instead are ubiquitousplasticizers and do occur in urban atmospheres. Thus the presence of thesecompounds in wax extracts further substantiates the findings of Hosker andLindberg (1982) and Shanley (1989) that leaf surfaces are an important sinkfor airborne particulate matter originating from anthropogenic sources.

CONCLUSION

The epicuticular waxes of the common tree species of the KIang Valley consistof the typical lipid fractions with minor biomarkers. Mesua ferrea had thehighest wax yield and Eugenia grandis the lowest. Hentriacontane (C

31) was the

dominant n-alkane for most species, followed by triu'iacontane (GJ3) andnonacosane (C2<) , respectively. The n-alkanoic acids had a Con'L' at Clli and C

20'

C24

, C28

or C32

• The n-alkanols had a Cmax at C28

for most species and at C26

, C3O'C

32or C

34for the others. One distinct feature that is observed in this study is

that the Cn,ax for Tl-alkan(>~ j. higher than thfl t reported for other locations. The

PertanikaJ. Sci. & Techno!. Vo!. 6 No.2, 1998 179

M. Radzi bin Abas and Bernd R.T. Simoneit

biomarkers identified are b-sitosterol, a- and b-boswellic acids (as the majorcomponents), a- and b-amyrins, a- and b-amyrones, friedelin and friedelanol.Other trace biomarkers are friedelane, olean-12-ene, taraxerene, squalene,dihydronyctanthic acid, dihydroroburic acid and dihydrocanaric acid. Thesebiomarkers are among the most common biomarkers identified in theaunosphere.

ACKNO~GEMENT

The analytical work was carried out by MRBA during his sabbatical visit atOregon State University.

REFERENCES

AIIA.~, M.RB., B.RT. SIMONEIT, V. EI.IAS, J.A. CAIIRAL AND J.N. CARDOSO. 1995. Compositionof higher molecular weight organic matter in smoke aerosol from biomass combustionin Amazonia. Chemosphere 30: 995-1015

ARIC;ONI, D., D.H.R BARTON, R BERNASCONI, C. I>IERASSI, J.S. MII.I.~ AND R.E. WOLFF. 1960.The constitutions of dammarenolic and nyctanthic acids. J. Chem. Soc. p.1900-1905.

BOR(;~~~ DEI. CA.~T1LLO, J., CJ.W. BROOKS, R.C. CAMillE, G.EGI.INTO , RJ. HAMILTON A D P.PI·:I.I.1TT. 1967. The taxonomic distribution of some hydrocarbons in Gymnosperms.Ph)'tochem. 6: 391-398.

BURKII.I., 1.H. 1935. A Dictionary of the Economic Products of the Malay Peninsula,Crown Agents for the Colonies, London.

CHEN, X.·J 1992. Oxygenated atural Products in Tropospheric Aerosols - Sources andTransport. M.Sc. Thesis. Oregon State University, Corvallis.

DOSKEY, P.V. AND AW. A DREN. 1986. Particulate- and vapor-phase n-alkanes in thenorthern Wisconsin atmosphere. Atmos. Environ. 20:1735-1744.

E<:I.I TON, G., AG. GOWALEZ, RJ. HAMII.TON AND RA RArHAE1..1962a. Hydrocarbonconstituents of the wax coatings of plant leaves: a taxonomic survey. Phytochemist I)'

1: 89-102.

E(;(.INTON, G., RJ. HAMILTON AND M. MARTIN-SMITH. 1962b. The alkane constituents ofsome New Zealand plants and their possible taxonomic implications. Ph),tochem. 1:137-145.

E<:I.INTON, G. AND RJ. HAMILTON. 1963. The distribution of alkanes. In Chemical PlantTaxononLy, ed. T. Swain, p. 187-217. London: Academic Press.

GA<:OSIAN, RB., D.C. ZAFIRIOU, E.T. PELTl.ER ANIlJ.B. ALFORIl.1982. Lipids in aerosols fromthe tropical North Pacific: temporal variabilityJ.Geoph)'s. Res. 87: 11133-11144.

HALL, D.H. Il RL. JONI'_~. 1961. Physiological significance of surface wax on leaves.Nattl1'e 191: 95-96.

HERIIIN, G.A AND P.A. ROlliNS. 1968a. Studies on plant cuticular waxes - 1. The chemo­taxonomy of alkanes and alkenes of the genus Aloe (Liliaceae).Phytochem. 7: 239­255.

HERIIIN, GA. ANIl RA. ROB! s. 1968b. Studies on plant cuticular waxes- II. Alkanes from

180 Pertanika.J. Sci. & Techno!. Vol. 6 No.2, 1998

Wax Lipids from Leaf Surfaces of Some Common planls of Malaysia

members of the genus Agave (Agavacea) the genera Kalanchoe, Eclll'lJPlia, Crassl/lia andSedllll! (Crassulaceae) and the genus ElIcol)1Jtl/S (M)'rtaceae) with an examination ofHutchinson's sub-di\~sion of the Angiosperms into Herbaceae and Lignosae. Phytochem.

7: 257-268.

HOSKER, JR., R.P. ANIl S.E. LINIlIIERC;. 1982. Review: Atmosphericdeposition and plantassimilation of gases and particles. Atmos. Environ. 16: 889-910.

J.-\~III·~"'ON, G.R. ANIl E.H. REID. 1972. The leaf lipids of some coniferspecies. Phytochemistl)"

11:' 269-275.

KOIXrrUKUDY, P.E. 1970. Plant waxes. LijJids 5: 259-275.

KOL-\ITUKudy, P.E. 1976. Chemistl) and Biochemistl) of Natural Waxes. p. 459. Amsterdam:Elsevier.

KOI.AITUKUIlY, P.E. 1980. Biopolyester membranes of plants: cutin and suberin. Science

208: 990-1000.

MARTIN, J.T. ANIl B.E. JUNIPER. 1970. The Cuticles of Plants. p. 347. London: E. ArnoldPublishers.

YfARTIN-S~IITII, M.. G. SUllRA~IA IAN A Il H.E. CON OR. 1967. Surface wax components offive species of Cortadetia (Gramineae) - a chemotaxonomic comparison. Phytochem.

6: 559-572.

MAWREK, M.A. ANIl B.R.T. SI~IONEIT. 1984. Characterization of biogenic and petroleumderived organic matter in aerosols over remote, rural and urban areas. In Identificationand Analysis of Organic Pollutants in Ail; ed. L.H. Keith, p. 353-370. Woburn, MA:Ann Arbor Science/Butterworth Publishers.

MAWREK, M.A., G.R. CASS ANIl B.R.T. SI~IONEIT. 1991. Biological inputLO visibility-reducingaerosol particles in remote arid Southwestern United States. Environ. Sci. Technol.

25: 684-694.

NISHIW>TO, S. 1974. A chemotaxonomic stud)' of n - alkanes in leaf surface waxes ofterrestrial plants. j. Sci. Hiroshima Univ., Ser. A 38: 151-158.

RIELEY, G., RJ. COJ.l.lER, D.M. JONKS AND G. ECJ.lNTO '. 1991. The biogeochemistry ofEllesmere Lake, UK.-I. Source correlation of leaf wax inputs to the sedimentary lipidrecord. Org. Geochem. 17: 901-912.

RO(;C;E, W.F., L.M. HILDHIANN, M.A. MAZUREK, G.R. CAS.S AND B.R.T. SI~IONEIT. 1993a.Sources of fine organic aerosols. 4. Particulate abrasion products from leaf surfacesof urban plants. Environ. Sci. Technol. 27: 2700-2711.

ROCC;E, W.F., M.A. MAWREK, L.M. HII.IlHIA ,G.R. G-\s.s ANIl B.R.T. SI~I()NEIT. 1993b.Quantification of urban organic aerosols at a molecular level: Identification,abundance and seasonal variation. AtlllOs. Environ. 27A: 1309-1330.

SAI.ASO(), I. 1987. Alkane distribution in epicuticular wax of some heath plants in onvay.Biochem. S)'st. Ecol. 15: 663-665.

SCHREIIIER, L. A DJ. ScHONHERR. 1992. Uptake of organic chemicals in conifer needles:surface adsorption and permeability of cuticles. Environ. Sci. Technol. 26: 53-159.

SHANLEY, J.B. 1989. Field measurements of dry deposition to spruce foliage and petri

Pertanika.J. Sci. & Technol. Vol. 6 0.2, 1998 181

M. Radzi bin Abas and Bernd R.T. Simoneit

dishes in the Black Forest, F.R.G.. Atmos. Environ. 23: 403-414.

SleRE, M.A, J.C. MARTY AND A. SAI.IOT. 1990. n-Alkanes, fatty acid esters, and fatty acidsalts in size-fractionated aerosols collected over the Mediterranean Sea. J. Geophys.Res. 95: 3649-3657.

SIMONEIT, B.R.T. 1977. Organic matter in eolian dusts over the Atlantic Ocean. Mar.Chell!. 5: 443-464.

SIMONEIT, B.RT. 1979. Biogenic lipids in eolian particulates collected over the ocean.In Proceedings Carbonaceous Pal1ides in the AlmosjJhere, ed. T. avakov, p.233-244. LBL­9037, SF and Lawrence Berkeley Laboratory.

SIMONEIT, B.R.T. AND M.A MAZUREK. 1982. Organic matter of the troposphere-II. Naturalbackground of biogenic lipid matter in aerosols over the rural Western UnitedStates. Alrnos. Environ. 16: 2139-2159.

SimONEIT, B.RT., RE. Cox AND LJ. STANDLEY. 1988. Organic matter of the troposphere­IV. Lipids in Harmattan aerosols of Nigeria. Almos Environ. 22: 983-1004.

SIMONEIT, B.RT. 1989. Organic matter of the troposphere-V: Application of molecularmarker analysis to biogenic emissions into the troposphere for source reconciliations.J. Alrnos. Chem. 8: 251-275.

SIMONEIT, B.RT., J. . CARDOSO A D N. ROBINSON. 1990. An assessment of the originand composition of higher molecular weight organic matter in aerosols oyerAmazonia. Chemosphere 21: 1285-130l.

SIMONEIT, B.RT., J. . CARDOSO AND . ROBINSON. 1991a. An assessment of terrestrialhigher molecular weight lipid compounds in aerosol particulate matter over theSouth Atlantic from about 30-700 S. Chenwsphere 22:447-465.

SIMONEIT, B.RT., PT. CRISP, M.A. MAZUREK AND LJ. STANDLEY. 1991b. Composition ofextractable organic matter of aerosols from the Blue Mountains and southeast coastof Australia. Environ. Inlernal. 17: 405- 419.reactive dye from wastewater. Text.Che1ll. CoL 28(5): 13-17.

STANDLEY, LJ. 1988. Determination of molecular signatures of natural and thermogenicproducts in tropospheric aerosols-input and transport. Ph.D. Thesis. Oregon StateUniversity, Corvallis.

STRANSKO(Y:), K, M. STREIl\L AND V. HEROUT. 1967. On natural waxes. VI.Distribution ofwax hydrocarbons in plants at different evolutionary levels. Coil. Czechoslov. Clum..Cornrnun. 32: 3213-3220.

TULLOCH, AP. 1976. Chemistry of waxes of higher plants. In Chemistl)' and Biochemistl)"of Nalural Waxes, ed. P.E. Kolattukudy, p. 235-287. Amsterdam : Elsevier.

WII_~, E.Rj., AG. HULsT AND j.G HARTOG. 1982. The occurrence of plant wax constituentsin airborne particulate matter in an urbanized area. Chemosphere 11: 1087-1096.

WOI.I.RAl~, V. 1967. Uber Naturwachse V. Kohlenwasserstoffe aus BHi.ttern und Fruchtendes Apfel- und Birnbaumes. Coll. Czechoslov. Chem. Co1ll1llun. 32: 1304-1308.

ZYGAI.DO, J.A., D.M. MAESTRI AND N.R. GROSO. 1994. Alkane distribution in epicuticularwax of some Solanaceae species. Biochem. 5yst. Ecol. 22: 203-209.

182 PertanikaJ. Sci. & Techno!. Vo!. 6 No.2, 1998