Chemical composition of essential oils of the tree Melaleuca quinquenervia (Myrtaceae) cultivated in Costa Rica

Abstract

Introduction: Melaleuca is a Myrtaceous genus of flowering plants of about 290 species, distributed throughout Indonesia, Papua New Guinea, Australia, and New Caledonia. Objective: To identify the chemical composition of the essential oils from leaves, twigs and fruits of M. quinquenervia cultivated as ornamental in Costa Rica. Methods: The essential oils were obtained through the steam distillation process in a Clevenger type apparatus. The chemical composition of the oils was done by GC-FID and GC-MS, using the retention indices on a DB-5 type capillary column in addition to mass spectral fragmentation patterns. Results: The essential oils consisted mainly of terpenoids (88,2-96,6%). A total of 88 compounds were identified, accounting for 93.1-97.0% of the total amount of the oils. The major constituents from the leaf oil were 1,8-cineole (31,5%), viridiflorol (21,7%), and α-pinene (17,9%). The fruit essential oil consisted mainly of viridiflorol (42,1%), α-pinene (15,0%), limonene (6,4%), α-humulene (4,7%), β-caryophyllene (3,9%), and 1,8-cineole (3,4%). The major components of twigs oil were viridiflorol (66,0%), and 1,10-di-epi-cubenol (4,0%). Conclusion: The plants introduced in Costa Rica belong to chemotype II whose oils contain as major constituents 1,8-cineole and viridiflorol, and it suggest that the original plants were brought from southern Queensland or northern New South Wales (Australia) or from New Caledonia.