Barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is a problematic weed in rice (Oryza sativa L.) fields. Overapplication of herbicides causes environmental pollution and the emergence of resistant weeds, and integrated weed management methods can reduce dependence on herbicides. The growth of E. crus-galli and rice seedlings was shown to be significantly inhibited by high concentrations of fulvic acid (FA, C14H12O8) under flooding conditions (HF, 0.80 g L−1) (P < 0.05). In contrast, seedling growth was promoted by the application of very low concentrations of FA (LF, 0.02 g L−1). The activities of glutathione S-transferase (GST) and antioxidant enzymes, including total superoxide dismutase (T-SOD), peroxidase (POD), and catalase (CAT), in E. crus-galli seedlings were enhanced by the LF treatment; while POD activity decreased and GST, T-SOD, and CAT activity was not significantly altered by the HF treatment. The metabolomic and transcriptomic analyses showed that FA regulated E. crus-galli seedling growth by affecting the synthesis of indole derivatives and flavonoid compounds. Compared with the blank control (CK, 0 g L−1), the levels of four indole derivatives were upregulated under the HF treatment, and the indole derivatives were slightly downregulated under the LF treatment. The flavonoids, including naringenin, naringenin chalcone, eriodictyol, kaempferol, and epigallocatechin, were downregulated under HF treatment, and the growth of E. crus-galli was reduced. In contrast, the metabolism and transcription of flavonoids were not significantly altered by the LF treatment. The addition of 0.80 g L−1 FA obviously inhibited the growth of newly sprouted E. crus-galli, whereas rice growth was significantly promoted 8 d after rice planting (P < 0.05). The application of FA, therefore, might be a potential integrated weed management method to control the damage caused by E. crus-galli in paddy fields.

Due to side-effects and inefficiency of the drugs used in malaria treatment, finding alternative medicine with less side-effects has attracted much attention. In this regard, in the present study, nanocomposite synthesized and its effects on the metabolites of P. falciparum were investigated. Subsequent to synthesis of nanocomposites, characterization was carried out using nuclear magnetic resonance (NMR), liquid chromatography-mass spectrometry (LC-MS), scanning electron microscopy, dynamic light scattering and Fourier-transform infrared tests. Solubility and drug release were measured and its toxicity on Vero cell was assessed using the MTT assay. The antiparasitic effect of the nanocomposite on the metabolites of P. falciparum was investigated by 1H NMR spectroscopy. Among synthesized nanocomposites, the average size of 239 nm showed suitable solubility in water as well as slow drug release. The MTT assay showed no toxicity for Vero cell lines. Concentrations of 2.5 μg mL−1 of nanocomposite eliminated 82.6% of the total parasites. The most effected metabolic cycles were glyoxylate and dicarboxylate metabolism. In this study, 1H NMR spectroscopy was used with untargeted metabolomics to study the effect of the nanocomposite on P. falciparum. Playing an essential role in understanding drug-target interactions and characterization of mechanism of action or resistance exhibited by novel antiprotozoal drugs, can be achieved by targeting metabolic using LC-MS.