Characterization and Antioxidant Activity of Essential Oil of Four Sympatric Orchid Species.

Annalisa Giovannini,Jacopo Calevo,Aldo Tava,Francesco Saverio Robustelli Della Cuna,Cinzia Boselli,Elia Bari

doi:10.3390/molecules24213878

Abstract

The volatile fractions from fresh inflorescences of naturally growing orchids Anacamptis coriophora (L.) R. M. Bateman, Pridgeon & M. W. Chase subsp. fragrans (Pollini), Anacamptis pyramidalis (L.) R. Ophrys holosericea (Burm.) Greuter and Serapias vomeracea (Burm. f.) B. were isolated by steam distillation and analyzed by GC/FID and GC/MS. Saturated hydrocarbons were quantified as the major constituents of the volatile fraction (47.87–81.57% of the total essential oil), of which long-chain monounsaturated hydrocarbons accounted from 9.20% to 32.04% of the total essential oil. Double bond position in linear alkenes was highlighted by dimethyl disulfide derivatization and MS fragmentation. Aldehydes (from 3.45 to 18.18% of the total essential oil), alcohols (from 0.19% to 13.48%), terpenes (from 0.98 to 2.50%) and acids (0.30 to 2.57%) were also detected. These volatiles compounds may represent a particular feature of these plant species, playing a critical role in the interaction with pollinators. DPPH assay evaluating the antioxidant activity of the essential oils was carried out, showing a dose-dependent antioxidant activity.

Highlights

Pollination of flowers by animals is often influenced by a wide variety of volatile molecules [1,2].The floral scent in plants has the primary aim to attract and guide pollinators [3,4], playing a critical role both in long- and short-distance attraction [2,5,6]
The essential oil obtained by steam distillation from fresh inflorescences were evaluated as 1.3 mg for A. coriophora subsp. fragrans, 1.8 mg for A. pyramidalis, 2.6 mg O. holosericea and 3.4 mg for S. vomeracea, respectively
The main represented volatiles constituents are saturated hydrocarbons, especially in A. coriophora subsp. fragrans followed by S. vomeracea, O. holosericea and A. pyramidalis, and unsaturated hydrocarbons mainly present in O. holosericea essential oil

Summary

Introduction

Pollination of flowers by animals is often influenced by a wide variety of volatile molecules [1,2].The floral scent in plants has the primary aim to attract and guide pollinators [3,4], playing a critical role both in long- and short-distance attraction [2,5,6]. The floral scent may influence/drive pollinator constancy [3,8], which ensures pollen transfer, reduces pollen loss and contributes to maintaining both the plant reproductive fitness and their barriers among species [9,10]. Additional functions of floral volatile chemicals occur as defensive and protective mechanisms vs biotic and abiotic stresses [11,12,13]. This may explain the wide variety of volatiles fragrances emitted by orchids acting as key characters to drive pollinators when food or sexual deception takes place [2]

Methods

Results

Conclusion