Phytochemistry and Allelopathic Effects of Tanacetum vulgare L. (Tansy) Extracts on Lepidium sativum L. (Garden Pepper Cress) and Lactuca sativa L. (Lettuce)

Abstract

Tanacetum vulgare is a perennial plant growing wild along roadsides, pastures, and agricultural fields. Its prevalence is due to several factors: good climatic adaptability, high self-seeding potential, phenotypic plasticity, multiplying via underground rhizomes and its allelochemicals, which influence the seed germination, root development and the overall vegetation of the surrounding plants. The phytochemistry of tansy extracts and their allelopathic activity on the seed germination and growth of garden pepper cress (Lepidium sativum L.) and lettuce (Lactuca sativa L.) were investigated. The major volatile compounds, 1,8-cineole, camphor and borneol were determined in tansy flower extracts. The leaf extracts contained appreciable amounts of 1,8-cineole and borneol. Feruloylquinic, (di)ferulic and dehydrocaffeoyl-5-caffeoylquinic acids, acacetin, ludovicin С and tanacetin were determined both in leaf and inflorescence extracts. Root extracts contained minor quantities of some terpenoids and polyphenols. Extracts of T. vulgare’s aerial parts showed strong allelopathic effects on model plants. The flower and leaf water extracts inhibited lettuce and pepper cress seed germination and growth the most. According to the fractions, the acidic solution had the strongest effect, followed by neutral and alkaline solutions. At the highest relative concentrations of 0.5 and 1.0 tansy leaf acidic fraction, lettuce seed germination and growth decreased by 89.93% (from 35.07 ± 4.79 to 3.53 ± 2.10 mm) and by 98.46% (from 35.07 ± 4.79 to 0.57 ± 0.98 mm) compared to the control, respectively. Tansy root extracts showed weak effects. Our results demonstrated that the allelopathic inhibitory potential of tansy extracts was higher on garden pepper cress than on lettuce. The presence of allelochemicals in T. vulgare may have a significant impact on plant communities and ecosystems.