Zonal Effect on the Essential Oil Profile from <i>Cymbopogon citratus</i> (Lemongrass) Leaves and <i>Citrus sinensis</i> (Orange) Peels harvesting in Mali

Nowadays, <i>Cymbopogon citratus</i> (DC.) Staph (Poaceae), (Lemongrass) and <i>Citrus sinensis</i> (L.) Osbeck (Rutaceae), (orange) are very coveted for aromatic, food and medicinal purposes. Lemongrass leaves and orange zests are reputed to be rich in essential oils, which are highly prized by the food industry. The aim of this study was to determine the essential oil (EOs) extraction yields and their profile of these species collected in three agro-ecological zones of Mali. EOs were extracted by steam distillation and their profile was determined by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). All registered data revealed zonal variation of extraction yields as well as in EO components (p-value < 0.05). Extraction yields varied from 0.32±0.02 to 0.44±0.03% for lemongrass and 0.32±0.01 to 0.50±0.03 for orange. These yields were higher in Sahelian zones for both species. Moreover, chromatography technique highlighted an important diversity of lemongrass and orange peel in individual EO components. Thus, Retention factors values recorded from TLC allowed to detect a maximum of different EO individuals: 15 for lemongrass and 13 for orange, mainly in Sahelian. Similarly with GC technique, more EO elements were found: a total of 23 for orange zests samples and 17 for lemongrass. Samples collected in Sudano-guinean sites presented the highest number of total individual EO constituents, 16 for orange and 12 for lemongrass. The major individual EO components were Limonene (43.14±0.20%), Neral (36.00±0.14%), and M-Camphorene (19.88±0.17%) for leaves of lemongrass, and carvone (19.59±0.58%), Citral (17.99±0.01%), and Neral (17.48±0.10%) for orange zests. This richness and diversity could be useful to better valorization of lemongrass leaves and orange peel in Mali.