Antimicrobial activity of Inula helenium L. essential oil against Gram-positive and Gram-negative bacteria and Candida spp.

In this work we report results regarding the in vitro antimicrobial activity of Inula helenium L. dried root extracts obtained by stepwise supercritical fluid extraction (SFE) and by hydrodistillation (HD). Inula helenium L. (Compositae family) is a perennial plant widely occurring in Europe and East Asia. Its oil is one of the richest sources of sesquiterpenoid lactones, which have strong anthelminthic activity and have the potential to induce detoxifying enzymes [1,2]. Inula helenium L. roots (C-040705130905) were purchased from Minardi (Bagnacavallo-Ravenna, Italy).

Extraction was carried out in a semibatch mode: batch charging of vegetable matter and continuous flow solvent. HD was performed for 4 h in a circulatory Clevenger-type apparatus up to exhaustion of the oil contained in the matrix, which was the same material as used in the SFE.