Soybean is a high-value food source, and the invasive weeds Mexican prickly poppy (Argemone ochroleuca) could release allelochemicals that inhibit the growth of this crop. The impact of A. ochroleuca on the germination and growth of soybean is not well documented. Therefore, the aim of this study was to evaluate the TLC profiles of different extracts of A. ochroleuca and assess the effects of extracts on the germination of soybean seeds. Shoots and roots of A. ochroleuca were weighed and 100 g of each was separately extracted with 1000 mL deionized water, hexane or acetone. Ten concentrations of water extracts ranging from 10 to 100 mL per 100 mL of deionized water and three concentrations of acetone and hexane extracts ranging from 2.5 to 7.5 g/L were separately used for seed germination bioassays. Thin-layer chromatography (TLC) analysis was used to compare the chemical profiles in the shoot and root water, and in the hexane and acetone extracts of A. ochroleuca. The highest reduction was recorded from the water extract, at 100%. The TLC profiling of A. ochroleuca addressed different classes of compounds, including alkaloids, phenolic acids and flavanoids. There is, however, a need to identify the most active phytochemicals in the suppression of germination.

Argemone ochroleuca Sweet is an alien invasive weed dominating most cultivated lands, however, the phytochemicals present in this plant and the effects of these on the germination and growth of economically important crops such as maize are not well-documented. The objective of the study was to characterize the phytochemistry of the shoots and roots of A. ochroleuca and determine whether the extracts could inhibit the germination of maize seeds. The shoots and roots of A. ochroleuca were extracted in water, hexane, and acetone. Ten maize seeds were used in the germination bioassay. A phytochemical analysis was conducted using gas chromatography-mass spectrometry (GC-MS). The effects of the A. ochroleuca water, hexane, or acetone extracts on maize seed germination were concentration and plant-part dependent. The highest reduction was recorded from the water extract with 82%. Identified compounds with high percentages in A. ochroleuca were 9,12-octadecadienoic acid (Z,Z) and 9,12,15-octadecatrienoic acid, (Z,Z,Z)-. The present study indicated that A. ochroleuca extracts suppress the germination of maize seeds, likely due to the presence of both the identified and potentially unidentified phytochemicals that were not detected by the selected method. There is, however, a need to establish the relationship between the phytochemical compounds and the enzymes responsible for germination.

Argemone ochroleuca is an invasive alien weed that poses a significant threat to crop production through the release of phytochemicals associated with inhibiting seed germination in several crops. However, the phytochemical composition of A. ochroleuca and the potential molecular interactions of its phytochemicals with maize proteins associated with seed germination remain insufficiently understood. Therefore, this study aimed to characterise the phytochemical profile of A. ochroleuca extracts and investigate the potential interactions of selected phytochemicals with maize proteins associated with seed germination using molecular docking. Key maize proteins involved in seed germination were virtually screened against phytochemicals identified from A. ochroleuca extracts. 9,12-Octadecadienoic acid (Z,Z), 2-hydroxy-1-(hydroxymethyl) ethyl ester exhibited the most favourable predicted binding affinity towards Zea mays β-glucosidase-1, while 9,12,15-octadecatrienoic acid showed a favourable predicted interaction with maize casein kinase. Roots and shoots of A. ochroleuca were extracted using hexane and acetone, and their phytochemical composition was characterised using liquid chromatography–mass spectrometry (LC–MS). The major compounds identified included 9,12-octadecadienoic acid (Z,Z), 1-hexacosanol, 9,12,15-octadecatrienoic acid (Z,Z,Z), Z-10-tetradecen-1-ol acetate, n-hexadecanoic acid, and α-sitosterol. The findings indicate that A. ochroleuca contains diverse phytochemical constituents, with selected compounds exhibiting potential interactions with maize proteins involved in seed germination. These in silico findings provide preliminary molecular insights that require experimental validation.