Antifungal activity of essential oils of four medicinal plants on fungi isolated from potato tubers (Solanum tuburosum) from the El Oued region (Eastern Algerian Northern Sahara)

Abstract

The aim of this study is to investigate the chemical composition of essential oils extracted from the aerial parts of four plants: Mentha spicata L, Mentha pepirita L, Mentha pulegium L, and Ocimum basilicumL, in order to evaluate their antifungal properties against several pathogenic fungi isolated from post-harvest potato tubers.The essential oils were extracted through hydrodistillation and analyzed using gas chromatography-mass spectrometry (GC-MS)The results revealed that M. pulegium has the highest content of essential oils with a yield of 2.1%, followed by M. spicata (1.4%), M. piperita (0.83%), and O. basilicum (0.19%).M.spicata is composed of (-)-Carvone (41.66%) and exo-2,7,7-trimethylbicyclo[2.2.1]heptane (10.28%).(-)-Carvone is the main component of M.piperita (48.74%), followed by cis-dihydrocarvone (7.96%) .The essential oil of M. pulegium is characterized by the presence of (-)-carvone as the main component with a content of 30.89%, isopelugone (23.62%).The volatile essence of O. basilicum contains linalool (26.16%), estragole (16.69%).The antifungal activity of the essential oils was evaluated using the direct contact method against the mycelial growth of the tested strains. The results indicated a high potential for antifungal activity against the tested strains.The essential oils of Mentha spicata showed a 100% antifungal effect against Fusarium proliferatum at a concentration of 0.90% and 0.95% for Alternaria alternata,Rhizoctonia solani,and Wickerhamomyces anomalus.Regarding the essential oils of Mentha piperita, a complete inhibition (100%) of mycelial growth was also achieved against all tested strains, at concentrations of 0.95% and 1%, and at 0.87% for Wickerhamomyces anomalus and 0.90% for A. alternata. The essential oil of Mentha pulegium has a fungicidal inhibitory effect at a concentration of 0.97% on Alternaria alternata and Fusarium proliferatum, and at 0.95% on Wickerhamomyces anomalus and Rhizoctonia solani. Regarding the essential oils of Ocimum basilicum, a complete inhibition (100%) of mycelial growth of fungal strains was achieved at a concentration of 0.97% for all strains except Wickerhamomyces anomalus, for which the fungicidal effect was obtained at a concentration of 1% .The obtained results, pave the way for the utilization of essential oils as an alternative to chemical fungicides.