Plantas medicinais e aromáticas
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Allelopathic and Antimicrobial Activities of Leaf Aqueous and Methanolic Extracts of Verbena officinalis L. and Aloysia citrodora L. (Verbenaceae): A comparative study.

Benzarti Saoussen, Imen Lahmayer, Sana Dallali, Wihed Chouchane and Helmi Hamdi

Two Verbena species (Verbena officinalis L. and Aloysia citrodora L.) were investigated to analyze their total phenolic and flavonoids content, DPPH free radical scavenging activity, allelopathic activity and antimicrobial activity. The total phenolic content (Folin-Ciocalteu assay) was shown to be between 160 μg GAE/mg dry weight basis (V. officinalis) and 360.03 μg GAE/mg dry weight basis (A. citrodora). The total flavonoids content (aluminum chloride method) was shown that, total flavonoids content varied from 7.91 to 10.62 μg QE/g DW in V. officinalis and from 11.70 to 12.93 μg QE/g DW in A. citrodora. The antioxidant activity was determined by using a DPPH radical scavenging assay and their antimicrobial activity was determined by utilizing an agar disc diffusion assay. Methanol extracts of the two species analyzed showed high antioxidant activity and among them A. citrodora possessed the highest quantity (249.31 mM ACE/g DW). The aqueous extracts of the species were found to inhibit the germination and radicle elongation of canary grass (P. canariensis L.) and lettuce (L. sativa L.). The methanol extracts showed antibacterial activities against a number of microorganisms. These findings suggest that the aqueous and methanol extracts of the plants tested contain compounds with allelopathic and antimicrobial properties. These exhibited properties propose that such plant extracts can possibly be used as natural preservatives in the food and pharmaceutical industries.