Chemotaxonomy of Indonesian Citrus maxima based on Leaf Essential Oils

Pummelo (Citrus maxima) is one of true citrus species originated from South East Asian regions. Pummelo is known as having high morphological diversity, but lacking of comprehensive publications documenting chemical diversity. The objectives of this study were to reveal essential oil diversity and its implication on the chemotaxonomy of the species. Leaves from forty individual plants were collected from seven districts representing pummelo distribution areas in Indonesia. Isolation of essential oils was done using maceration and solvent extraction procedures. Qualitative and quantitative analysis of the essential oils was conducted using GC-MS. Thirty one compounds were identified, consisted of monoterpenes, sesquiterpenes, diterpenes, ketones, alkenes and fatty acids. Assessment on chemotaxonomical importance of essential oils was carried out using cluster analysis and principal component analysis on volatile compounds. Three chemotypes were recognized, defined as “nerol/loliolide/allo-aromadendrenechemotype”, “alpha-selinenechemotype” and “alpha-pinene/delta-carenechemotype”. Three chemotypes defined in this study was the first reported chemotaxonomic analysis for Indonesian C. maxima.