Composição química do óleo volátil de Myrcianthes nativas da região sul do Brasil

Abstract

ABSTRACT: “Chemical composition of the volatile oils of native Myrcianthes species from South Brazil”. The essential oil of Myrcianthes gigantea (Myrtaceae) leaves, which were collected in Rio Grande do Sul (Southern Brazil), was obtained by hydrodistillation in a Clevenger apparatus. The chemical investigation was performed by GC-FID and GC-MS. Thirty-six compounds were identifi ed accounting for 90.1% of the oil content. The analyzed species was rich in cyclic sesquiterpenes, mainly those from the germecrane cyclization pathway, among them spathulenol (28.8%) and its isomer, iso-spathulenol (9.5%). Leaves of M. cisplatensis and M. pungens were also collected in the same region and the analysis of the oil composition was compared with those previously reported for collections from other countries in South America. M. cisplatensis oil showed a high content of monoterpenes (56.3%), specially from the p-mentane and pinane groups, with three major compounds: 1,8-cineole (29.8%), limonene (10.9%) and α-pinene (8.9%). These fi ndings are in agreement with those reported previously. For M. pungens, thirty-six compounds were identifi ed without a predominant component. β-caryophyllene (10.1%), with caryophyllane skeleton, was the main substance for this sample. For this species the oil composition was quite different from those related for two exemplars collected in Argentina, in which both oil were rich in monoterpenes. This result suggests the occurrence of chemotypes.