Sulphides and furanones from steam volatile oils of Allium fistulosum and Allium chinense

The constituents of the steam volatile oils from two kinds of Allium fistulosum, A. fistulosum var. caespitosum and A. chinense, have been investigated by GC and spectral techniques (IR, UV, GC/MS, ¹H NMR and ¹³C NMR). The compounds identified from the neutral fraction of each volatile oil included sulphides, thiolanes, alcohols, aldehydes, ketones, furanones and others. Among the sulphur compounds, dipropyl disulphide comprised ca 28% of A. fistulosum oil, ca 23% of A. fistulosum var. caespitosum oil and ca 30% of A. chinense oil. A. fistulosum oil was characterized by a large quantity of tridecan-2-one (ca 52%) and 2,3-dihydro-2-octyl-5-methylfuran-3-one (ca 16%). Also, a large amount of 2,3-dihydro-2-hexyl-5-methylfuran-3-one (ca 20%) was isolated from A. chinense oil.