| Summary: | A detailed chemical composition of <i>Dendrobium</i> essential oil has been only reported for a few main species. This article is the first to evaluate the essential oil composition, obtained by steam distillation, of five Indian <i>Dendrobium</i> species: <i>Dendrobium chrysotoxum</i> Lindl., <i>Dendrobium harveyanum</i> Rchb.f., and <i>Dendrobium wardianum</i> R.Warner (section <i>Dendrobium</i>), <i>Dendrobium amabile</i> (Lour.) O’Brien, and <i>Dendrobium chrysanthum</i> Wall. ex Lindl. (section <i>Densiflora</i>). We investigate fresh flower essential oil obtained by steam distillation, by GC/FID and GC/MS. Several compounds are identified, with a peculiar distribution in the species: Saturated hydrocarbons (range 2.19–80.20%), organic acids (range 0.45–46.80%), esters (range 1.03–49.33%), and alcohols (range 0.12–22.81%). Organic acids are detected in higher concentrations in <i>D. chrysantum</i>, <i>D. wardianum</i>, and <i>D. harveyanum</i> (46.80%, 26.89%, and 7.84%, respectively). This class is represented by palmitic acid (13.52%, 5.76, and 7.52%) linoleic acid (<i>D. wardianum</i> 17.54%), and (<i>Z</i>)-11-hexadecenoic acid (<i>D. chrysantum</i> 29.22%). Esters are detected especially in species from section <i>Dendrobium</i>, with ethyl linolenate, methyl linoleate, ethyl oleate, and ethyl palmitate as the most abundant compounds. Alcohols are present in higher concentrations in <i>D. chrysantum</i> (2.4-di-tert-butylphenol, 22.81%), <i>D. chrysotoxum</i> (1-octanol, and 2-phenylethanol, 2.80% and 2.36%), and <i>D. wardianum</i> (2-phenylethanol, 4.65%). Coumarin (95.59%) is the dominant compound in <i>D. amabile</i> (section <i>Densiflora</i>) and detected in lower concentrations (range 0.19–0.54%) in other samples. These volatile compounds may represent a particular feature of these plant species, playing a critical role in interacting with pollinators.
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