Characterization of seasonal and chemotypical variability in the essential oil from leaves of Annona neosalicifolia H. Rainer (Annonaceae)

The essential oil (EO) from leaves of Annona neosalicifolia H. Rainer (Annonaceae) obtained from two chemotypes in the southern Brazilian Atlantic Rainforest was analysed both by GC-FID and GC-MS. Forty compounds were identified, accounting for 95.9 to 99.5% of the total oil in each sample. The VOs were characterized by the predominance of sesquiterpenes in all samples, being main compounds bicyclogermacrene (13.9-41.8%) and beta-caryophyllene (9.3-26.3%); germacrene D was also found in high amounts, but its concentration was more variable. Monoterpene compounds were absent in the summer and fall samples, with higher concentrations in winter samples (6.1-7.4% for α-pinene and 6.4-11.2% for β-pinene). EO from chemotype II was characterized by a high concentration of the sesquiterpene alcohol (E)-nerolidol (36.3%), which was absent or in trace amounts in chemotype I. The characterization of these seasonal and individual variations in the chemical composition of the essential oil from A. neosalicifolia may have agronomical implications and may be important in the understanding and delimitation of the metabolic plasticity of the highly variable taxon A. emarginata as well.