Chemical Composition and Allelopathic Potential of Essential Oils from Citharexylum spinosum L. Grown in Tunisia.
Citharexylum spinosum L. (Verbenaceae) also known as Citharexylum quadrangulare Jacq. or Citharexylum fruticosum L. is an exotic tree introduced many years ago in Tunisia, specially used as a street and park ornamental tree. Essential oils (EOs) were obtained by hydrodistillation of the different parts (roots, stems, leaves, flowers and fruits; drupes) collected from trees grown in the area of Monastir (Tunisia). In total, 84 compounds, representing 90.1 - 98.4% of the whole oil composition, were identified by GC-FID and GC/MS analyses. The root EO was distinguished by its high content in monoterpene hydrocarbons (α-phellandrene; 30.8%) whereas that obtained from stems was dominated by sesquiterpene hydrocarbons (cuparene; 16.4%). The leaf oil was rich in an apocarotenoid derivative (hexahydrofarnesylacetone; 26%) and an aliphatic hydrocarbon (nonadecane; 14.5%). Flowers oil was rich in esters (2-phenylethyl benzoate; 33.5%). Finally, drupes oil was rich in oxygenated sesquiterpenes (β-eudesmol; 33.1%). Flowers oil showed a significant phytotoxic effect against lettuce seeds germination, it induces a total inhibition when tested at 1 mg/ml. Root and shoot elongation seemed to be more affected than germination. The inhibition of the shoot length varied from 3.6% to 100% and that of the root from 16.1% to 100%. The highest inhibition of 100% was detected for flower oil tested at 1 mg/ml. Our in vitro studies suggest a possible and new alternative use of C. spinosum EOs in herbicidal formulations, further experiments involving field conditions are necessary to confirm its herbicidal potential.
Laboratory of Genetics Biodiversity and Valorisation of Bio-resources (LR11ES41), High Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia.
Asma
A
El Ayeb-Zakhama
Laboratory of Genetics Biodiversity and Valorisation of Bio-resources (LR11ES41), High Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia.
Lamia
L
Sakka-Rouis
Dipartimento di Farmacia, Università di Pisa, Via Bonanno 33, IT-56126, Pisa, Italy.
Guido
G
Flamini
Laboratory of Heterocyclic Chemistry, Natural Products and Reactivity, Team: Medicinal Chemistry and Natural Products, Faculty of Sciences of Monastir, University of Monastir, Monastir, Tunisia.
Hichem
H
Ben Jannet
Laboratory of Genetics Biodiversity and Valorisation of Bio-resources (LR11ES41), High Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia.
Fethia
F
Harzallah-Skhiri
D064089:Allelopathy / Q000502:physiology*; D057168:Distillation; D004952:Esters / Q000302:isolation & purification; D035264:Flowers / Q000633:toxicity; D008401:Gas Chromatography-Mass Spectrometry; D018525:Germination / Q000187:drug effects; D006540:Herbicides / Q000302:isolation & purification; D018545:Lactuca / Q000187:drug effects / Q000254:growth & development; D039821:Monoterpenes / Q000302:isolation & purification; D009822:Oils, Volatile / Q000737:chemistry* / Q000494:pharmacology; D018514:Plant Structures / Q000737:chemistry; D012717:Sesquiterpenes / Q000302:isolation & purification; D014416:Tunisia; D029648:Verbenaceae / Q000737:chemistry*
D004952:Esters; D006540:Herbicides; D039821:Monoterpenes; D009822:Oils, Volatile; D012717:Sesquiterpenes

Citharexylum spinosum
; 
Lactuca sativa
; Allelopathy; Chemical characterization; Essential oils