Identification of chemical components from essential oils and aqueous extracts of some medicinal plants and their nematicidal effects on Meloidogyne incognita

Background Essential oils from aerial parts of Achillea wilhelmsii, Tanacetum polycephalum and Teucrium polium were isolated by using Clevenger-type apparatus and tested at different concentrations for their nematicidal activity against the second stage juvenile (J2) of Meloidogyne incognita in vitro condition. The chemical components of the essential oils and seed extracts of each plant (0.2 g) were extracted with maceration with methanol/acetic acid mixture (85:15, v/v). Analysis was done by Gas Chromatography, GC-Mass Spectrometry) and HPLC. Identified chemical components were tested after this on J2 of M. incognitain. Nuclear magnetic resonance spectroscopy was done to investigate the properties of organic molecules by drawing their spectrum using Broker AVANCE AQS-300 MHz. Results Significant difference was achieved on nematicidal activity of essential oils based on the plant species and oil concentrations. GC and GC-MS led to identification of 41, 39 and 45 major compounds from T. polium, T. polycephalum and A. wilhelmsii oils, respectively. A number of 10 components with different ranges of percentage were recorded in all of the tested plants oils. Use of HPLC resulted in identification of 4, 3 and 2 chemical compounds in the extracts of A. wilhelmsii, T. polycephalum and T. polium, respectively. The nematicidal activity of commercial polyphenols at the concentration of 1100 ppm showed 58.3, 48.9, 28.2 and 26.8 percentages J2 mortalities by catechin, coumarin, gallic acid and chlorogenic, respectively. Nematotoxicity test of commercial terpenoids showed the highest J2 mortalities (more than 80%), in concentrations of 100 and 200 ppm limonene, beta-pinene and alpha-pinene. However, it was less than 30% of J2 mortality caused by terpinen-4-ol, alpha-terpineol and linalool. Conclusions Compounds such as Limonene, beta-pinene and alpha-pinene were detected in all of the tested plants, A. wilhelmsii, T. polycephalum and T. polium, having an effective nematicidal action versus terpinen-4-ol, alpha-terpineol and linalool.