Chemical Composition and Allelopathic Potential of Essential Oils from Citharexylum spinosum L. Grown in Tunisia

• Published in: Chemistry & biodiversity 2017-04, Vol.14 (4), p.np-n/a
• Main Authors: El Ayeb‐Zakhama, Asma, Sakka‐Rouis, Lamia, Flamini, Guido, Ben Jannet, Hichem, Harzallah‐Skhiri, Fethia
• Format: Article
• Language: English
• Subjects: Allelopathy; Allelopathy - physiology; Chemical characterization; Citharexylum; Citharexylum fruticosum; Citharexylum spinosum; Distillation; Essential oils; Esters - isolation & purification; Flowers - toxicity; Gas Chromatography-Mass Spectrometry; Germination - drug effects; Herbicides - isolation & purification; Lactuca - drug effects; Lactuca - growth & development; Lactuca sativa; Monoterpenes - isolation & purification; Oils, Volatile - chemistry; Oils, Volatile - pharmacology; Plant Structures - chemistry; Sesquiterpenes - isolation & purification; Tunisia; Verbenaceae; Verbenaceae - chemistry
• ISSN: 1612-1872; 1612-1880
• DOI: 10.1002/cbdv.201600225

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.