Identification of impact aroma compounds in Eugenia uniflora L. (Brazilian Pitanga) leaf essential oil

Abstract

O óleo essencial das folhas de Eugenia uniflora L. (Myrtaceae) foi obtido a partir do arraste a vapor em aparelhagem de Clevenger e analisado por cromatografia gasosa acoplada à espectrometria de massas. As folhas foram colhidas e imediatamente extraídas durante cinco dias consecutivos, às 9 e 14h, não sendo observada variação significativa no rendimento dos óleos extraídos no período. Furanodieno e seu produto de rearranjo, furanoelemeno (ou curzereno, num total de 50,2%), β-elemeno (5,9%) e α-cadinol (4,7%) foram os constituintes majoritários. Pela técnica de cromatografia gasosa-olfatometria (CG-O), associada à análise por diluição de aroma AEDA (Aroma Extract Dilution Analysis), foi possível identificar nove substâncias ativas no aroma do óleo de pitanga, sendo que três foram consideradas como de maior impacto: furanodieno (juntamente com furanoelemeno, FD 1024), β-elemeno (FD 256) e (E,E)-germacrona (FD 256). A mistura destas três substâncias, coletadas a partir do CG-sniffing port, levou a uma essência de pitanga de aroma bastante semelhante à fruta, de acordo com a avaliação por análise olfativa comparativa.The leaf essential oil of Eugenia uniflora L. (Myrtaceae) was extracted by Clevenger apparatus and analysed by gas chromatography-mass spectrometry (GC-MS). The leaves were collected and immediately extracted for five consecutive days at 9:00 am and 2:00 pm. No variance in the oil yields were observed in the period. Furanodiene and its rearrangement product, furanoelemene (or curzerene, 50.2%), β-elemene (5.9%) and α-cadinol (4.7%) were identified as the most abundant compounds. GC-Olfatometry (GC-O) associated to Aroma Extract Dilution Analysis (AEDA) allowed the identification of nine active aroma compounds, where furanodiene (along with furanoelemene, FD 1024), β-elemene (FD 256) and (E,E)-germacrone (FD 256) were characterized as the main impact aroma compounds in the odor of this essential oil. Those substances were collected through a sniffing port adapted on the GC allowing to obtain a typical essence of pitanga as indicated by comparative olfatometric analysis.Keywords: Eugenia uniflora L., Myrtaceae, gas chromatography olfatometry-mass spectrometry, sesquiterpenes, AEDA IntroductionEugenia uniflora L. (syns. E. michelii Lam.; Stenocalyx michelii Berg; Plinia rubra Vell.), native of Brazil, is commonly found as bushes which could grow as trees reaching up to 8 meters high, depending upon the cultural practices used. Its reddish fruits grow to the size of pumpkin shaped cherries, with a sweet and sour taste. The young leaves present a pinkish color, which turns into a glossy dark green as they age. Hand crushed leaves release a very pleasant odor with strong fresh and woody notes.1 The tea obtained from the leaves of E. uniflora has been used in folk medicine against fever, infections and to lower blood pressure. Studies discussing the pharmacological activity of this species can be found in the literature.2 Pitanga (Portuguese common name for Eugenia uniflora L. fruit) is appreciated in ice cre...

A new approach for quantifying furanodiene and curzerene: a case study on the essential oils of Eugenia uniflora L., Myrtaceae (pitangueira) leaves

“…The fragments were collected from 40 to 450 u. Identification of oil components was based on the Kovats index, comparison of their mass spectral fragmentation patterns with the Mass Spectra libraries (Wiley 139, 275 and 7 and Nist 127), published data (Weyerstahl et al, 1988;Henriques et al, 1993;Lima et al, 1993;Morais et al, 1996;Maia et al, 1999;Ogunwande et al, 2005;Melo et al, 2007;Costa et al, 2009Costa et al, , 2010Peixoto et al, 2010) and myrrh essential oil injection (Mölleken et al, 1988). The GC-MS quantification was obtained using the total ions chromatogram (TIC) and was expressed as an average of the data obtained for three samples of extracted leaf oil.…”

“…Some authors have reported the same retention time for both components (Melo et al, 2007), while others reported differences (Morais et al, 1996;Mölleken et al, 1998;Baldovini et al, 2001;Baser et al, 2003;Bertoli et al, 2004;Oguwande et al, 2005;Yang et al, 2005Yang et al, , 2007Raj et al, 2008;Wong et al, 2009;Joshi et al, 2009).…”

“…Several studies have examined the composition of oil from the leaves of E. unifl ora L. from different regions in Brazil and other countries (Weyerstahl et al, 1988;Morais et al, 1996;Henriques et al, 1996;Maia et al, 1999;Holetz et al, 2002;Melo et al, 2007;Costa et al, 2009;Peixoto et al, 2010). Such studies have shown that in the essential oil of pitangueira leaves the composition and concentration of components are very complex.…”

“…Excepting this, the minor components present in the sample are well known in essential oils from pitangueira leaves, from South to North Brazil and are also similar to oils from Nigeria. Curzerene is also the principal component in essential oils from pitangueira leaves from Rio de Janeiro (50.2%, Melo et al, 2007), Goiás (42.6%, bright red fruit pitangueira, Costa et al, 2010), Goiás (34.8%, Peixoto et al, 2010) and Nigeria (19.7%, Ogunwande et al, 2005).…”

Indução de fitoalexinas em cotilédones de soja em resposta a derivados de folhas de pitangueira

“…Em folhas de E. uniflora, o composto furanodieno e seu produto de rearranjo, furanoelemeno ou curzereno (50,2%), ß-elemeno (5,9%) e a-cadinol (4,7%) foram os constituintes majoritários (MELO et al, 2007). Possivelmente o óleo essencial, pela forma de obtenção e por ser um produto concentrado, apresente maior diversidade e concentração de substâncias com ação elicitora.…”