Chemical Composition and Antimicrobial and Allelopathic Activity of Tunisian Conyza sumatrensis (Retz.) E.Walker Essential Oils

• Published in: Chemistry & biodiversity 2013-02, Vol.10 (2), p.209-223
• Main Authors: Mabrouk, Samia, Salah, Karima Bel Hadj, Elaissi, Ameur, Jlaiel, Lobna, Jannet, Hichem Ben, Aouni, Mahjoub, Harzallah-Skhiri, Fethia
• Format: Article
• Language: English
• Subjects: Allelopathy; Anti-Infective Agents - chemistry; Anti-Infective Agents - isolation & purification; Anti-Infective Agents - pharmacology; Antimicrobial activity; Asteraceae; Bacterial Infections - drug therapy; Candida albicans; Candida albicans - drug effects; Conyza; Conyza - chemistry; Conyza sumatrensis; Enterococcus faecalis; Enterococcus faecalis - drug effects; Essential oils; Flowers & plants; Fungi - drug effects; Gas Chromatography-Mass Spectrometry; Humans; Matricaria; Matricaria ester; Microbial Sensitivity Tests; Microbiology; Mycoses - drug therapy; Oils, Volatile - chemistry; Oils, Volatile - isolation & purification; Oils, Volatile - pharmacology; Proteus mirabilis; Proteus mirabilis - drug effects; Raphanus - drug effects; Raphanus - growth & development; Raphanus sativus; Staphylococcus aureus; Staphylococcus aureus - drug effects; Tunisia
• ISSN: 1612-1872; 1612-1880
• DOI: 10.1002/cbdv.201200117

Conyza sumatrensis (Retz.) E.Walker (Asteraceae) is a spontaneous annual herb, fairly widespread throughout Tunisia, which has rarely been studied or valued in any sector. Essential oils were obtained by hydrodistillation of different parts (flower heads, leaves, stems, and roots) of C. sumatrensis plants, which were collected in autumn (November 2007) at the flowering stage in the area of Monastir, Tunisia. In total, 98 compounds, representing 88.1–99.3% of the oil composition, were identified by GC‐FID and GC/MS analyses. The root essential oil was distinguished by its high content in acetylenes (matricaria ester, 4; 74.3%), while those from flower heads and leaves were dominated by oxygenated sesquiterpenes (61.1 and 50.3%, resp.). The oils of C. sumatrensis from Tunisia belonged to a matricaria ester/caryophyllene oxide chemotype. All the oils were evaluated for antibacterial, antifungal, and allelopathic activities. The results indicate that the leaf oil exhibited significant in vitro antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Proteus mirabilis and that the C. sumatrensis oils isolated from the aerial parts presented high mycelia‐growth inhibition of Candida albicans and the filamentous fungi tested. Moreover, the essential oils of the different plant parts inhibited the shoot and root growth of Raphanus sativus (radish) seedlings. Indeed, the inhibition of the hypocotyl growth varied from 28.6 to 90.1% and that of the radicle from 42.3 to 96.2%.