Study On The Aromatic Constituents Of Some Osmanthus Fragrans Cultivars In China

Osmanthus fragrans Lour., a species in the family Oleaceae, is one of China's ten top traditional flowers. Endemic to southwestern China, O. fragrans has given rise to numerous cultivars through millennia of natural selection and artificial breeding. O. fragrans is famed for its rich fragrance,which remains little studied.The present study selected representative members of the four O. fragrans cultivar groups. Gas chromatography/mass spectrometry (GC/MS) was used to conduct qualitative and quantitative analyses of the volatile aromatic components given off by the cultivars. Optimal extraction time and temperature were determined through comparative analysis. We also identified major differences in volatile aromatic component compositions of the cultivars, as well as the characteristic aromatic components of O. fragrans. The results are as follows:1. We believe that Headspace Solid-Phase Microextraction (HS-SPME) is an ideal technique for extracting volatile aromatic components of O. fragrans. Best results may be achieved using 65μm PDMS at 55℃for 45 min.2. Using the HS-SPME and GC/MS techniques,we detected 58 volatile aromatic components from the O. fragrans cultivars under study. Alcohols and terpenes are the predominant components. In O. Fragrans cultivars from Kaifeng, 30 volatile aromatic components were detected, many of which were ester compounds of relatively high concentrations.3. We found that O. fragrans cultivars differ significantly in both the identity of main aromatic compounds and the composition of volatile aromatic compoents.4. The Luteus Group cultivars contained high concentrations of linalools; the Albus Group cultivars had linalools, nonanals, linalool compounds, and ionones in more or less similar concentrations; the Aurantiacus Group cultivars had relatively few aromatic components; the Asiaticus Group cultivars had low concentrations of chemical compounds and lacked some major aromatic components. The Asiaticus Group appears to be the most aromatic of the four cultivar groups.