Antifungal Activity of Cyperus articulatus, Cyperus rotundus and Lippia alba Essential Oils against Aspergillus flavus Isolated from Peanut Seeds

<i>Aspergillus flavus</i> is a cosmopolitan saprophytic fungus that infests several foodstuffs and is associated with adverse effects in humans. In Senegal, significant losses of groundnut production are mainly due to contamination caused by this species. This study evaluated in vitro antifungal activities of <i>Cyperus articulatus</i>, <i>Cyperus rotundus</i> and <i>Lippia alba</i> essential oils against <i>A. flavus</i> isolated from peanut seeds. Essential oils obtained by hydrodistillation of rhizomes of the two <i>Cyperus</i> species and leaves of <i>L. alba</i> were analyzed with GC-DIF and GC-MS. The essential oil yields from <i>C. articulatus</i>, <i>C. rotundus</i> and <i>L. alba</i> were 1.1%, 1.3% and 1.7%, respectively. These three samples had the following chemotypes: (i) mustakone (21.4%)/eudesma-4(15)-7-dien-1β-ol (8.8%)/caryophyllene oxide (5.9%), (ii) caryophyllene oxide (25.2%)/humulene epoxyde 2 (35.0%) and (iii) geranial (46.6%)/neral (34.6%). The three oils tested inhibited the growth of <i>A. flavus</i> at concentrations between 100 and 1000 ppm. The <i>L. alba</i> oil was the most effective with total clearance of <i>A. flavus</i> on PDA. For the essential oils of <i>C. rotundus</i> (93.65%) and <i>C. articulatus</i> (78.11%), the highest inhibition rates were obtained with a 1000 ppm dose. Thus, <i>L. alba</i> oil could be used safely as an effective protector of groundnuts against <i>A. flavus</i>.