A influência sazonal na composição química dos óleos essenciais das folhas de Eugenia uniflora de um biótipo de cor de fruto vermelho-alaranjado indicou a presença de dois grupos de óleos em relação às duas estações do Cerrado brasileiro. O grupo I incluiu amostras coletadas na estação seca (abril-setembro), caracterizadas por conterem as mais altas percentagens de espatulenol (10%) e óxido de cariofileno (4,1%). No grupo II, com amostras coletadas na estação úmida (outubro-março), o constituinte majoritário foi o epóxido de selina-1,3,7(11)-trien-8-ona (29%). A correlação canônica indicou que o espatulenol e o óxido de cariofileno apresentaram um forte relacionamento com o balanço de nutrientes (S, Ca, Fe) e os fenólicos foliares, enquanto o epóxido de selina-1,3,7(11)-trien-8-ona foi correlacionado ao conteúdo de K, Cu, Mn e a precipitação nos meses da estação úmida. Os sesquiterpenos oxigenados predominaram em todas as amostras e a variação química nos óleos essenciais parece ser determinada pelo ambiente com uma clara influência sazonal.Seasonal influence on the chemical composition of essential oils of Eugenia uniflora leaves with red-orange fruit colour biotype has indicated the presence of two oil clusters in the two seasons of the Brazilian Cerrado. Cluster I included samples collected during dry months (April-September) which were characterized by the highest percentages of spathulenol (10%) and caryophyllene oxide (4.1%). In cluster II, whose samples were collected during wet months (October-March), the major constituent was selina-1,3,7(11)-trien-8-one epoxide (29%). The canonical correlation indicated that spathulenol and caryophyllene oxide revealed a strong relationship with the phenolics and nutrient balance (S, Ca, Fe) in leaves, whereas selina-1,3,7(11)-trien-8-one epoxide was related to K, Cu, Mn, and precipitation during the months of the wet season. Oxygenated sesquiterpenes were predominant in all the sampling months and the oil chemovariation observed might be environmentally determined by a clear seasonal influence.Keywords: Eugenia uniflora, Myrtaceae, essential oil, seasonal influence, principal component analysis, canonical correlation analysis
IntroductionEugenia uniflora L. (Myrtaceae) is a Brazilian shrubby tree with edible cherry-like fruits which is locally known as "pitangueira". Its leaves have been used in folk medicine for the treatment of diarrhea, 1,2 inflammation, 1 hyperglycemia, hyperlipidemia, hypertriglycemia, 3,4 and hypertension. In addition, they have been used as an antimalarial [5][6][7] and spasmolytic agent 6,8 as well as an inhibitor of DNA polymerase, maltase, sucrase, and α-glucosidase.
4,9Phytochemical studies have mainly focused on the essential oil and polyphenolic constituents of the leaf. [9][10][11][12][13][14][15][16] Antimicrobial activities have been reported for essential oils and expressed juice, including bacterial and dermatophyte isolates. [17][18][19] Previous studies have identified the ellagitannin oenothein B as responsible for the inhibition ...
