Essential oil composition, antioxidant and antibacterial activities of wild and cultivated Lavandula mairei Humbert

International audienceLavandula mairei is an endemic and rare plant species growing in the mountains from the southeast to the southwest of Morocco. It is an aromatic and medicinal plant widely used in traditional medicine for the treatment of various diseases. To our knowledge, no data are available on the chemical composition and the biological activities of L. mairei essential oils (EOs). The aim of this study was to investigate the effect of cultivation on the chemical composition, antioxidant and antibacterial activities of EOs isolated from L. mairei. The hydrodistilled oils obtained from wild and cultivated L. mairei were analyzed by GC/ MS. Twenty-three compounds were identified representing more than 98% of both EOs (wild and cultivated). Oils were characterized by high amount of carvacrol (78.29 and 76.61% for wild and cultivated EO respectively). The antioxidant and antibacterial assays revealed that the two EOs tested showed significant activities. The results highlighted that cultivation affected neither the chemical composition nor the biological activities of L. mairei. Cultivation of L. mairei may constitute an alternative to the conservation of this species

Chemical characterization and antifungal activities of four Thymus species essential oils against postharvest fungal pathogens of citrus

International audienceThe aim of this study was to find an alternative to synthetic fungicides currently used in the control of postharvest fungal diseases of citrus. Antifungal activities of essential oils from four Thymus species were investigated against Penicillium digitatum, Penicillium italicum and Geotrichum citri-aurantii. The essential oils, obtained by hydrodistillation from aerial parts of four Thymus species were submitted to gas chromatography hyphenated with mass spectrometry analysis. The main constituents were carvacrol (76.94%) for Thymus leptobotrys, borneol (27.71%) and thymol (18.47%) for Thymus satureioides subsp. pseudomastichina, camphor (46.17%) and-terpineol (7.69%) for Thymus broussonnetii subsp. hannonis and carvacrol (32.24%),-terpinene (19.60%) and p-cymene (13.52%) for Thymus riatarum. In the in vitro mycelial growth assay, complete inhibition of the three pathogens was obtained by T. leptobotrys and T. riatarum essential oils, at 1000 l L −1. The effect of essential oils on spore germination varied significantly between tested Thymus species. T. leptobotrys essential oil displayed the highest bioactivity, inhibiting completely the spore germination of G. citri-aurantii at 250 l L −1 and of P. digitatum and P. italicum at 500 l L −1. T. riatarum essential oil was able to inhibit completely the spore germination of G. citri-aurantii (2000 l L −1) and both Penicillium species used as target organisms (1000 l L −1). The essential oil of T. leptobotrys had the lowest minimum inhibitory concentration (MIC) for the three pathogens (MIC value < 500 l L −1). These findings suggest that essential oils obtained from T. leptobotrys, T. riatarum and T. satureioides subsp. pseudomastichina may be useful and effective agents for control of citrus fungal pathogens