Effect of Drying on Chemical Constituents of Peel Essential Oils of Cleopatra Mandarin (L) Grown in the North Central of Nigeria

ABSTRACT:

In this study, the oil extracts from fresh and dried peels of Cleopatra mandarin were isolated and characterized via GC-MS technique. Also the study established both quantitative and qualitative variation in chemical constituents of the essential oils of Cleopatra mandarin (L) cultivated in the North central of Nigeria. Fresh and dried pulverized peels of Cleopatra 

mandarin (500g) were separately hydro distilled and afforded oil in the range 0.2- 0.8%(w/w) respectively. GC/MS analysis of this oils revealed the abundance of monoterpenoids and sesquiterpenoids whose composition are in the ranges (10.4%- 99.1%) and (3.6%-48.6%) respectively. The predominant constituents detected in the oils were citral (1.7-20.6%); eugenol (16.3%); nerol (2.5-10.0%); L-carvone (10.0%); D-carvone (3.2 -8.0%); α- caryophyllene (1.3-9.8%); garmacrene D (0.8-4.2%); α- trans bergamotene (3.0-15.0%); ϒ-elemene (7.0%); geraniol (5.9%) and 4-hexyl-2,5-dihydro-2,5-dioxo-3-furan acetic acid (27.4-72.4%). Other terpenoids that were detected in appreciable quantities in the oils include: 3-carene(1.3-1.4%); α-terpinolene (2.5%) and bicyclogermacrene (1.4%); Z,E-α-farnesene (1.1%); humulene(0.9%); δ-cadinene (0.8-2.0%); alloaromadendrene (2.0-2.5%); elixene (2.3%); eremophilene (1.2%); ϒ-cadinene (3.1%); himachala-3(12),4-diene (1.7%); α-sinensal (1.0%); α-acorenol (1.6%). However, the quantities of the predominant constituents of the oils varied significantly. These variations in the regime of volatile compounds present in the oils are attributable to the differences in the volatility of the compounds of the oils from the peels subjected to different drying conditions.

Keywords: Essential oils, Cleopatra mandarin, gas chromatography (GC), GC/ mass spectrometry (MS), Terpenes, Monoterpenes, Sesquiterpene, mevalonate pathway, Non- mevalonate pathway.