In this study, researchers from Algeria evaluated the phytotoxicity of essential oils extracted from two Labiatae (mint) species, namely, Thymus fontanesii and Satureja calamintha. Their findings were published in the Journal of Essential Oil Research.
T. fontanesii (Algerian thyme) and S. calamintha (lesser calamint) essential oils were tested against some of the most harmful weeds in Algeria.
These included Sinapis arvensis (wild mustard), Avena fatua (common wild oat), Sonchus oleraceus (common sowthistle), Xanthium strumarium (rough cocklebur) and Cyperus rotundus (nutgrass).
The researchers first obtained the essential oils via hydrodistillation and analyzed them using gas chromatography and mass spectrometry.
They reported that T. fontanesii essential oil contained the following dominant compounds:
Carvacrol, 52.1 percent
Thymol, 13.3 percent
P-cymene, 12.2 percent
y-Terpinene, 8.1 percent
Meanwhile, the S. calamintha essential oil contained:
1,8-cineole, 28.4 percent
Pulegone, 10.2 percent
Menthone, 9.7 percent
Isomenthone, 9.6 percent
Bio-assessments showed that both essential oils had strong herbicidal effects on seed germination (at 0.01, 0.02 and 0.03 percent) and 3-4 leaf stage weeds (at 1, 2 and 3 percent).
These effects were attributed to their ability to disrupt physiological processes.
Benchaa S, Hazzit M, Zermane N, Abdelkrim H. CHEMICAL COMPOSITION AND HERBICIDAL ACTIVITY OF ESSENTIAL OILS FROM TWO LABIATAE SPECIES FROM ALGERIA. Journal of Essential Oil Research. 12 February 2019;31(4):335–346. DOI: 10.1080/10412905.2019.1567400