Chemical diversity of the Melaleuca cajuputi leaf oils from six locations in southern Vietnam

Melaleuca cajuputi Powell, a member of Myrtaceae family, is a popular and valuable plant in Vietnam, especially in the southern region. In this study, gas chromatography-mass spectrometry was used to determine the diversity in chemical composition of M. cajuputi leaf oil collected from six sites in the South of Vietnam. A total of sixty compounds has been identified from the essential oils of M. cajuputi leaf, such as α-thujene, α-pinene, benzaldehyde, β-pinene, β-myrcene, α-phellandrene, α-terpinene, benzene, 1-methyl-2-(1- methylethyl), 1,8-cineole, γ-terpinene, etc. Among those, five compounds were found in all six samples including α-thujene, α-pinene, α-phellandrene, γ-terpinene, and α-terpinolene, whereas other compounds were only present in some samples with varying amounts. Principal Component Analysis (PCA) has been performed to examine the similarities in the composition of leaf oils among the collection sites using XLSTAT software. The results from PCA suggested that six samples of leaf oil could be classified into 2 chemotypes with different chemical constituents. Note that 1,8-cineole only occurred in chemotype group 1 whereas it was omitted in chemotype group 2. This finding explains the diversity of bioactivity of M. cajuputi collected from different regions and provide more information on M. cajuputi for further application in medicine and food industry.