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...