Screening of Tunisian plant extracts for herbicidal activity and formulation of a bioherbicide based on Cynara cardunculus

• Published in: South African journal of botany Vol. 128; pp. 67 - 76
• Main Authors: Kaab, S.B., Rebey, I.B., Hanafi, M., Hammi, K.M., Smaoui, A., Fauconnier, M.L., De Clerck, C., Jijakli, M.H., Ksouri, R.
• Format: Journal Article Web Resource
• Language: English
• Published: Elsevier B.V 01.01.2020; National Inquiry Services Centre
• Subjects: Activité herbicide; Bioherbicide; Biologie végétale (sciences végétales, sylviculture, mycologie...); Chemistry; Chimie; composés phénoliques; Extracts; extraits; Formulation; Herbicidal activity; Life sciences; Phenolic compound; Physical, chemical, mathematical & earth Sciences; Physique, chimie, mathématiques & sciences de la terre; Phytobiology (plant sciences, forestry, mycology...); plant extracts; Sciences du vivant; Extracts; Herbicidal activity; Phenolic compound; Formulation; Bioherbicide
• ISSN: 0254-6299; 1727-9321
• DOI: 10.1016/j.sajb.2019.10.018

The need to reduce the use of chemical pesticides currently fosters great interest in eco-friendly biological control agents. In addition, the isolation of plant allelopathic substances and the evaluation of their phytotoxic effects can lead to the discovery of new natural herbicides. In this context, our study aimed to assess the herbicidal activity of ten crude extracts obtained from aerial parts of Tunisian spontaneous plants against Trifolium incarnatum, Silybum marianum and Phalaris minor. It confirmed that the Cynara cardunculus methanolic extract best inhibited weed germination and seedling growth, and caused necrosis or chlorosis. Following a bioassay-guided fractionation, five main phenolic compounds, (1) syringic acid, (2) p-coumaric acid, (3) myricitrin, (4) quercetin and (5) naringenin were identified in the most active crude methanolic extract. Then, only 3 of the flavonoids contained in the most active fraction were tested on Trifolium incarnatum. The 3 compounds had a significant phytotoxic effect and therefore could be employed in a new composition of botanical herbicides to control crop weeds. Besides, a novel herbicide composition was designed to improve the post-emergence activity of the methanolic extract. The formulation containing the C. cardunculus crude methanolic extract showed the same herbicidal activity as the standard industrial bioherbicide containing pelargonic acid. These results make C. cardunculus a suitable source of natural compounds potentially usable as natural herbicides. [Display omitted] •C. cardunculus extract had the best herbicidal activity among 10 plant extracts.•Five phenolic compounds were identified in C. cardunculus.•Myricitrin, naringenin and quercetin were the main active compounds in C. cardunculus.•Fraction 2 of C. cardunculus had the same herbicidal effect as biological herbicide.