Volatile Constituents of Floral Scents from Encyclia cordigera (Kunth) Dressler and E. randii (Barb. Rodr.) Porto & Brade (Orchidaceae)

Abstract

Encyclia cordigera is native from Central America tropical region, and Encyclia randii occurs at Brazilian Amazon environment domains. Floral concentrates from both Encyclia species were extracted, analyzed by gas chromatography-mass spectrometry, and identified compounds belong to terpenoids, phenylpropanoids, and fatty acid derivatives classes. Primary constituents of the E. cordigera floral scent were β-ionol (45.4%), terpinen-4-ol (12.4%), benzyl benzoate (5.6%), and indole (5.0%). (2E,6Z)-Farnesol (24.9%), heptanal (11.8%), (E)-nerolidol (9.4%), nonanal (6.4%), p-vinyl-guaiacol (6.0%), and phenylethyl benzoate (5.3%) have predominated in the floral scent of E. randii. From the olfactory standpoint, E. cordigera scent was previously characterized as a blend of ionone-floral and aromatic-floral notes. Very likely, E. randii scent presents the woody fragrance due to sesquiterpenes (2E,6Z)-farnesol and (E)-nerolidol and the fruity note from the aldehydes heptanal and nonanal. Floral perfume plays a fundamental role in attracting pollinating insects, whose symbiosis contributes to the appearance of chemical variations in orchid species.