FLAVOUR AND FRAGRANCE JOURNAL

Flavour Fra`r[ J[ 1999^ 04] 321Ð322

Copyright Þ 1999 John Wiley + Sons\ Ltd[

Chemical composition of the essential oils of exudatesfrom Pinus oocarpa Schiede

Jesus Velasquez,1* Marıa E. Toro,1 Osvaldo Encinas,2 Luis Rojas3 and Alfredo Usubillaga3

1 Universidad Nacional Experimental de Guayana, Upata, Edo, Bolıvar, Venezuela2 Facultad de Ciencias Forestales y Ambientales, Universidad de Los Andes, Merida, Venezuela3 Instituto de Investigaciones, Facultad de Farmacia, Universidad de Los Andes, Merida, Venezuela

Received 2 March 1999

Revised 07 July 1999

Accepted 08 July 1999

ABSTRACT] Essential oil of exudates from Pinus oocarpa Schiede\ grown in the Andes of Venezuela\ was

obtained by hydrodistillation in a Clevenger!type apparatus[ A GCÐMS analysis showed that a!pinene and b!

pinene were the main constituents\ but the turpentine was also high in heptanes[ Copyright Þ 1999 John Wiley

+ Sons\ Ltd[

KEY WORDS] Pinaceae^ Pinus oocarpa^ turpentine^ oleoresin^ a!pinene^ terpenes^ heptanes

Introduction

The conifer Pinus oocarpa Schiede is native to tropicalAmerica\ from northern Mexico to south Nicaragua\and its distribution is wider than any other centralAmerican pine[0 In general\ the conifer trees exude vari!able quantities of oleoresin as a response to injury "path!ology oleoresin# or as a natural exudate "physiologyoleoresin#[1\2

Previous studies on P[ oocarpa|s oleoresin from cen!tral America have shown values of 04Ð29) of essentialturpentine\ which has a demand as disinfectant\ insec!ticide\ solvent and fragrance additive[2\3 Furthermore\there is a growing industrial demand for essential tur!pentine with high a! and b!pinene content\4 which isusually commercially obtained mainly from Pinus elli!

ottii "USA#\ P[ roxbur`hii "India# and P[ massoniana

"China#[ In Central America and some Caribbean coun!tries it is commonly obtained from P[ caribaea var[hondurensis and P[ oocarpa Scheide[2

Experimental

Sample Collection

Oleoresin samples were collected by wounding the stemof 01 healthy trees of P[ oocarpa Scheide growing in SanJavier del Valle\ selected using random tables[ The studyarea is located at 0[899Ð1[099 m above sea level[5 Dur!

�Correspondence to] J[ Vela�squez\ Universidad Nacional Experimental deGuayana\ Upata\ 7941\ Edo[ Bol(�var\ Venezuela[ E!mail] velasquezjÝlatinmail[com

ing the dry season "MarchÐApril#\ from each selectedtree\ two exudates "labelled A and B# were collectedwithout application of stimulants[

Isolation of Essential Oils

The volatile compounds of the oleoresins were sep!arated by hydrodistillation using a Clevenger!type trapfor 3 hours[ The physical properties of the essential oilswere measured using standard procedures[

Gas Chromatography

The compounds were separated and analysed using aPerkin!Elmer Autosystem Gas Chromatograph^ heliumat 0 ml:min was used as carrier gas[ The essential tur!pentine "9[4 ml# was injected without dilution at 199>Con a 59 m×9[14 mm i[d[ AT!4 capillary column "Deer!_eld\ IL\ USA#\ 9[14 mm _lm thickness[ The startingtemperature of 59>C "0 min# was increased to 199>C at3>C:min^ a second ramp of 09>C:min was applied to179>C and the _nd temperature was maintained for 19min[ The gas chromatograph was equipped with a FIDdetector operated at 179>C[ The peak areas were cal!culated using Turbochromm Navigator software[ Kov!a�ts indices were measured by comparison of retentiontimes with a series of n!alcanes[

Identification of Compounds

The identi_cation of the compounds was carried outusing a HP!4862 GCÐMS system[ A 29 m×9[14 mmi[d[ capillary column "Hewlett!Packard\ USA#\ 9[14 mm

Copyright Þ 1999 John Wiley + Sons\ Ltd[ Flavour Fra`r[ J[ 1999^ 04] 321Ð322

ESSENTIAL OILS OF PINUS OOCARPA EXUDATES 322

Table 1. Characterization of the essential oils in turpentine from Pinus oocarpa Scheide growing in SanJavier, Merida State, Venezuela

Kova�ts indices Compounds Exudate A "area )# Exudate B "area )# Identi_cation method

699[9 Heptane 26[96 00[46 CGÐMS\ IK891[6 n!Nonane 4[52 7[87 CGÐMS\ IK820[9 Tricyclene 9[02 9[11 CGÐMS\ IK832[4 a!Pinene 39[27 38[83 CGÐMS\ IK846[5 Camphene 9[79 9[72 CGÐMS\ IK860[3 Nonane 2!methyl 9[06 9[27 CGÐMS\ IK874[8 b!Pinene 3[42 03[12 CGÐMS\ IK880[8 Myrcene 9[53 0[50 CGÐMS\ IK

0924[9 Limonene 1[13 2[91 CGÐMS\ IK0090[9 Undecane 0[61 5[38 CGÐMS\ IK0120[9 3!Allyl anisole 1[86 9[05 CGÐMS\ IK1010[4 Isolongifolene 0[74 9[24 CGÐMS\ IK

_lm thickness was used[ The mobile phase was heliumat 0 ml:min and a split ratio of 099 ] 0[ The sample wasdiluted in pentane "14) v:v# and injected at 199>C usingthe same temperature programme as in the GC analyses[The mass spectrometer was registered in the scan modeat 69 eV and the identi_cation of the compounds wasmade using a Wiley library "5th edn#[

Results and Discussion

Exudate A "average harvest 499 g# contained 09) ofessential oil\ while exudate B "average harvest 239 g#produced 01) of essential oil[ The physical propertiesof both essential turpentines were as follows] Density"19>C#\ A�9[62\ B�9[7090^ optical rotation ðaŁ14>

D \A�−0[93\ B�−8[47^ refractive index "15>C#\A�0[3032\ B�0[3495[

Twelve compounds were identi_ed in both exudates"Table 0#[ Several researchers have reported a similarcomposition for the essential oil of Pinus oocarpa\4\6Ð09

but they do not mention the presence of n!heptane\nonane or undecane[ We found an unusually high con!tent of n!heptane[ On the other hand D!2carene and b!phellandrene\ mentioned as discriminatory compoundsin other studies\ are completely absent in all samplesexamined in this study[ These di}erences could be attri!buted to location and altitude[6\8Ð02

The presence of heptane in oleoresin is characteristicof several conifer species growing at higher altitudes03

"San Javier is located at 1999 m above sea level#[ Thiscompound could serve as a solvent and make the ~owof oleoresins easier forming a plastic protective coating\allowing the subsequent evaporation of monoterpenesand crystallization or oxidative polymerization of thediterpene resin acids on the injured surfaces[2\04

Exudate A showed a higher heptane content "26)#and a relatively high amount of a! and b!pinene "39)and 4)\ respectively# as well as n!nonane "4[52)#[ Exu!date B had a lower heptane content "00[46)# but a

higher content of a! and b!pinene "38[83) and 03[12)\respectively# and n!nonane "7[87)#[ In both exudates\other compounds amount to less than 2)[ Di}erencesbetween exudates have been reported also by Hillis2

and Gijzen et al[04 This was attributed to di}erences inresponse of the tree[ The essential oil density of Pinus

oocarpa Schiede in San Javier was found to be 9[654\lower than the average densities reported for other coni!fers[05\06 This lower density could be explained by thehigher heptane content found[

Acknowled`ements * We would like to thank the Colegio Fe y Alegr(�afor the gift of Pinus oocarpa samples and the Research Institute atthe Faculty of Pharmacy\ Los Andes University\ for the use of itsequipment and for technical assistance[

References

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