Volatile constituents of five species of Portlandia (Rubiaceae)

Portlandia (Rubiaceae) is a genus endemic to Jamaica. The volatile organic constituents of P. albiflora, P. coccinea, P. grandiflora, P. latifolia and P. proctorii were analyzed by headspace solid-phase microextraction (SPME) coupled with capillary mass spectrometry. The main constituents detected in these species are 1-penten-3-one, hexanal, (E)-2-hexenal, linalool, borneol and methyl salicylate. All species are rich in aliphatic aldehydes, mainly represented by (E)-2-hexenal, that range from 17% (P. latifolia) to 90% (P. coccinea) of total volatiles. The high content of aldehydes is characteristic to Portlandia species and may serve as a chemical marker to differentiate Portlandia from related genera within the Rubiaceae.