Volatile Constituents from the Fruits of FourSyzygium Species Grown in Malaysia

Abstract

The volatile constituents of five fruits from four Syzygium species from Malaysia were isolated by vacuum distillation with subsequent extraction of the distillates with dichloromethane. The concentrated extracts were analysed by capillary GC and GC-MS. Forty-three components were identified in roseapple (S. jambos Alston) volatiles, including 28 which have not been previously reported in this fruit. A total of 42, 39, 36 and 41 constituents were identified in water apple (S. aqueum Alston), wax jambu (S. samarangense Merr. & Perry) and two varieties of Malay apple (S. malaccense Merr. & Perry), respectively. The volatile compositions of these fruits were quite different. 3-Phenylpropan-1-ol, (E)-cinnamyl alcohol and other compounds with the C6-C3 skeleton constituted about 60% of roseapple volatiles, but were absent among the volatiles of the other Syzygium fruits. Water apple yielded the largest number and proportion (41.4%) of terpenoids, among which γ-terpinene was clearly dominant. The volatiles of wax jambu were characterized by the presence of a large number of C9 aldehydes and alcohols, and those of Malay apple by the very low terpenoid content (< 1.7%). The two varieties of Malay apple produced volatiles which showed much similarity regarding the number of compounds found in common, but differed widely in the proportions of some of the common constituents.