Phytotoxic mechanism of allelochemical liquiritin on root growth of lettuce seedlings

Enhanced herbicidal activity of coumarin via carbon dot nanoformulation: synthesis and evaluation

BACKGROUND

The integration of nanocarriers with biochemicals can markedly enhance the stability and efficacy of these agents, which will help to diminish the reliance on chemical pesticides, and contribute to the advancement of sustainable agricultural practices.

RESULTS

We prepared nanometer carbon dots (CDs) from black wolfberry (Lycium ruthenicum Murr.) and synthesized coumarin-loaded carbon dots (Cm-CDs) nanocomposites. The CDs exhibited a uniform distribution and high stability, with a coumarin loading rate of 65.45%. Experimental results on the herbicidal activity of both coumarin and Cm-CDs against Portulaca oleracea and Setaria viridis showed that, compared with coumarin alone, Cm-CDs completely inhibit the germination of S. viridis or prevent further development of P. oleracea post-germination at lower concentrations. The application of Cm-CDs has the potential to significantly diminish the biomass of P. oleracea and S. viridis (the dry weight decreased by 69.3% and 63.61% respectively), leading to a cessation of growth and the manifestation of wilting symptoms (P < 0.05). This indicates that the binding of coumarin to CDs markedly enhances the herbicidal efficacy of coumarin. Both coumarin and Cm-CDs exhibit consistent alterations in biomass, hormone levels, antioxidant enzyme activity, malondialdehyde (MDA) content, root morphology, and vitality, however, the effects observed with Cm-CDs were consistently more pronounced than those associated with coumarin (P < 0.05).

CONCLUSION

In both the germination bioassay and the pot experiment, Cm-CDs demonstrated stronger herbicidal toxicity. Both coumarin and Cm-CDs exhibit identical modes of action on P. oleracea and S. viridis. This study confirms that CDs can serve as effective nanocarriers to markedly enhance the herbicidal biological activity of coumarin in controlled conditions. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Elucidating the eco-friendly herbicidal potential of microbial metabolites from Bacillus altitudinis

Microbial herbicides play a vital role in agricultural preservation, amid growing concerns over the ecological impact from extensive development and use of chemical herbicides. Utilizing beneficial microbial metabolites to combat weeds has become a significant focus of research. This study focused on isolating herbicidal active compounds from Bacillus altitudinis D30202 through activity-guided methods. First, the n-butanol extract (n-BE) of B. altitudinis D30202 underwent fractionation using macroporous adsorption resin D101 and Sephadex LH-20, identifying Fr. F as the most potent segment against wild oats (Avena fatua L.). Ultra-performance liquid chromatography - quadrupole time-of-flight mass spectrometry (UPLC - QTOF-MS) identified nine compounds in the active fraction Fr. F. Subsequently, three subfractions (Fr.F-1 to Fr.F-3) were derived from Fr.F via semi-preparative liquid chromatography, resulting in methyl indole-3-acetate (MeIAA) purification. MeIAA, functioning as an auxin analog, exhibited effects of indole-3-acetic acid (IAA) on wild oats' growth, with a root length median inhibitory concentration of 81.06 µg/ml. Furthermore, we assessed MeIAA's herbicidal impact on five weed species across diverse families and genera, providing a first-time analysis of MeIAA's mechanism on wild oats. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed structural damage to leaves and roots post-MeIAA treatment. MeIAA treatment increased superoxide anion and hydrogen peroxide levels in wild oat roots, alongside with elevated peroxidase (POD) and superoxide dismutase (SOD) activity, chlorophyll-degrading enzymes (Chlase, MDACase), malondialdehyde (MDA) content, and relative conductivity in leaves. Conversely, it decreased catalase (CAT) activity and chlorophyll content. Therefore, this study provides a new material source and theoretical foundation for ecologically sustainable agricultural weed control.

Characterization key genes of Arabidopsis seedlings in response to β-caryophyllene, eugenol using combined transcriptome and WGCN analysis

Weeds present a significant challenge to high crop yield and quality. In our study, we investigated the phytotoxic activity of β-caryophyllene (BCP) and eugenol, which are natural allelopathic chemical compounds, on Arabidopsis seedlings. We found that these compounds inhibited the growth of Arabidopsis thaliana plants. When either BCP or eugenol was applied, it led to decrease in the content of cell wall components such as lignin, cellulose, hemicellulose, and pectin; and increase in the levels of endogenous hormones like ETH, ABA, SA, and JA in the seedlings. Through transcriptome profiling, we identified 7181 differentially expressed genes (DEGs) in the roots and shoots that were induced by BCP or eugenol. The genes involved in the synthesis of lignin, cellulose, hemicellulose, and pectin were down-regulated, whereas genes related to synthesis and signal transduction of ABA, ETH, SA, and JA were up-regulated. However, genes related to IAA synthesis and signal transduction were found to be down-regulated. Furthermore, we characterized 24 hub genes using Weighted Correlation Network Analysis (WGCNA). Among them, the identified 16 genes in response to BCP was primarily associated with hypoxia stress, while 8 genes induced by eugenol were linked to inhibition of cell division. Our results suggested that BCP and eugenol had ability to target multiple genes to inhibit growth and development of Arabidopsis plants. Therefore, they can serve as excellent candidates for natural biological herbicides.

Advances in the Mechanism of Luteolin against Hepatocellular Carcinoma Based on Bioinformatics and Network Pharmacology

As one of the most common malignant tumors, hepatocellular carcinoma (HCC) has a rising incidence rate and also seriously endangers human life and health. According to research reports, hepatitis B, hepatitis C, intake of aflatoxin in the diet, and the effects of alcohol and other chemicals can induce an increase in the incidence of liver cancer. However, in the current clinical treatment of HCC, most of the drugs are chemical drugs, which have relatively large side effects and are prone to drug resistance. Therefore, the development of natural compounds to treat HCC has become a new treatment strategy. Several studies have shown that flavonoids have shown outstanding effects and exhibit strong tumor growth inhibitory effects in vivo experimental studies. Luteolin, as a natural flavonoid, has anti-tumor, anti-inflammatory, anti-viral, anti-oxidation, immune regulation, and other pharmacological effects. The anti-cancer mechanism of luteolin mainly directly acts on tumor cells to inhibit their growth, induce cell apoptosis, reduce tumor tissue angiogenesis, regulate long non-coding RNA, affect immunogenic cell death, and regulate autophagy. As well as improving the curative effect of radiotherapy and chemotherapy and chemoprevention. In this study, we evaluated the function of luteolin in regulating cancer cell proliferation, migration, and invasion will summarize and analyze luteolin and its mechanism of regulating HCC to improve the role of luteolin in the clinical prevention and treatment of HCC.

Reduction of Weed Growth under the Influence of Extracts and Metabolites Isolated from Miconia spp

Weeds pose a problem, infesting areas and imposing competition and harvesting difficulties in agricultural systems. Studies that provide the use of alternative methods for weed control, in order to minimize negative impacts on the environment, have intensified. Native flora represents a source of unexplored metabolites with multiple applications, such as bioherbicides. Therefore, we aimed to carry out a preliminary phytochemical analysis of crude extracts and fractions of Miconia auricoma and M. ligustroides and to evaluate these and the isolated metabolites phytotoxicity on the growth of the target species. The growth bioassays were conducted with Petri dishes with lettuce, morning glory, and sourgrass seeds incubated in germination chambers. Phytochemical analysis revealed the presence of flavonoids, isolated myricetin, and a mixture of quercetin and myricetin. The results showed that seedling growth was affected in a dose-dependent manner, with the root most affected and the seedlings of the lettuce, morning glory, and sourgrass as the most sensitive species, respectively. Chloroform fractions and myricetin were the most inhibitory bioassays evaluated. The seedlings showed structural changes, such as yellowing, nonexpanded cotyledons, and less branched roots. These results indicate the phytotoxic potential of Miconia allelochemicals, since there was the appearance of abnormal seedlings and growth reduction.

Prdx6-induced inhibition of ferroptosis in epithelial cells contributes to liquiritin-exerted alleviation of colitis

Inhibition of ferroptosis in intestinal epithelial cells ameliorates clinical symptoms and improves endoscopic presentations in inflammatory bowel disease (IBD). Licorice is used worldwide in food and medicine fields. Liquiritin, a flavonoid component in licorice, is an effective substance used as an anti-inflammatory, antioxidant food that has been shown to improve chemically induced colitis. Herein we evaluated the therapeutic effects of liquiritin on colitis and determined whether liquiritin could affect colitis by modulating ferroptosis in epithelial cells. A colitis model was induced in mice by oral administration with 2.5% DSS dissolved in drinking water. The results showed that liquiritin significantly alleviated symptoms, suppressed intestinal inflammation and restored the epithelial barrier function in the colitis mouse model. Liquiritin supplementation upregulated colonic ferritin expression, increased the storage of cellular iron, reduced the cellular iron level and further inhibited ferroptosis in epithelial cells from the colitis model. Pharmacological stimulation of ferroptosis largely blocked liquiritin-induced alleviation of colitis. Peroxiredoxin-6 (Prdx6) expression was significantly decreased in the DSS group, which was reversed by liquiritin treatment. Genetic or pharmacological silencing of Prdx6 largely reversed liquiritin-induced modulation of the ferritin/iron level and ferroptosis in epithelial cells. Molecular docking results showed that liquiritin could bind to Prdx6 through the hydrogen bond interaction with amino acid residues Thr208, Val206 and Pro203. In conclusion, liquiritin treatment largely alleviated DSS induced colitis by inhibiting ferroptosis in epithelial cells. Liquiritin negatively regulated ferroptosis in epithelial cells in colitis by activating Prdx6, increasing the expression of ferritin and subsequently reducing the cellular iron level.

Allelopathic and competitive interactions between native and alien plants

The novel-weapons and homeland-security hypotheses are based on the idea that aliens and natives are not adapted to each other’s allelochemicals as they did not co-evolve. However, as only a few studies have tested this, it remains unclear how important co-evolutionary history is in determining the strength of allelopathic interactions between aliens and natives. Here, we tested for potential pairwise allelopathic effects on each other of five alien and five native herbaceous species in China. We did a germination experiment and a competition experiment. In the germination experiment, we tested whether aqueous extracts of the ten study species had allelopathic effects on each other’s seed germination. In the competition experiment, we tested whether the alien and native species differed in their competitive effects and responses, and whether these were changed by the presence of activated carbon—a presumed allelopathy neutralizer– in the soil. Plant extracts had negative allelopathic effects on seed germination. This was particularly the case for extracts from the native species. Moreover, aqueous extracts had slightly stronger negative effects on germination of the aliens than on germination of the natives. In the competition experiment, on the other hand, the natives suffered more from competition than the alien species did, but we could not relate this to allelopathy. Alien plants had negative competitive and allelopathic effects on native plants, but the reverse was also true. These alien-native interactions, however, were not consistently stronger or weaker than native-native or alien-alien interactions.