Phytotoxic effects of essential oils ofNepeta curvifloraBoiss. andNepeta nudaL. subsp.albifloragrowing wild in Lebanon

Abstract

The chemical composition of the essential oils of two Nepeta species collected in Lebanon was studied by means of GC and GC-MS analysis. The essential oil from N. curviflora Boiss. contained high amounts of bcaryophyllene (41.6%), caryophyllene oxide (9.5%), (E)-b-farnesene (6.2%) and (Z)-b-farnesene (4.8%); in the oil from N. nuda L. subsp. albiflora (Boiss.) Gams. collected in Laklouk the main compounds were b-bisabolene (11.8%), pulegone (10.8%), (E,Z)-nepetalactone (8.0%), (E)-b-farnesene (7.1%) and caryophyllene oxide (6.9%), while N. nuda L. subsp. albiflora collected in Tannourine Cedar Forest contained high percentages of hexadecanoic acid (10.1%), b-bisabolene (7.8%), caryophyllene oxide (7.3%), pulegone (7.2%) and (E,Z)-nepetalactone (4.4%). The effects of the essential oils on germination and initial radical elongation of Raphanus sativus L. (radish) and Lepidium sativum L. (garden cress) were studied, resulting in a significant inhibitory activity against radical elongation of the species tested.

Chemical Composition and Possible in Vitro Phytotoxic Activity of Helichrsyum italicum (Roth) Don ssp. italicum

“…The essential oil was evaluated for its phytotoxic activity against germination and initial radicle elongation of radish and garden cress, two species frequently utilized in biological assays [30]. The germination of radish and garden cress did not appear significantly sensitive to the essential oil (Table 2).…”

Chemical Composition and Phytotoxic Effects of Essential Oils from Four Teucrium Species

“…The four essential oils were evaluated for their phytotoxic activity against germination and initial radicle elongation (Table 2) of radish and garden cress, two species usually utilized in biological assays [21]. Also the main components of these oils were assayed for the same activity ( Table 3).…”

Chemical Composition and Phytotoxic Effects of Essential Oils of Salvia hierosolymitana Boiss. and Salvia multicaulis Vahl. var. simplicifolia Boiss. Growing Wild in Lebanon

“…The study of compounds produced by plants, which inhibit or stimulate the germination and the development of other plants, is important for understanding the mechanisms of the ecological interaction. For this reason, our research group is carrying out a series of studies on the possible allelopathic properties of medicinal plants [ 4 ] that, being rich in active principles, are considered a primary source of potential allelochemicals. Aromatic species, in particular, are toxic almost without exception and the degree of toxicity seems to vary in effectiveness roughly with the intensity of aroma.…”