In recent years, the increase in antibiotic resistance demands searching for new compounds with antimicrobial activity. Phytochemicals found in plants offer an alternative to this problem. The genus Pelargonium contains several species; some have commercial use in traditional medicine such as P. sinoides, and others such as P. peltatum are little studied but have promising potential for various applications such as phytopharmaceuticals. In this work, we characterized the freeze-dried extracts (FDEs) of five tissues (root, stem, leaf, and two types of flowers) and the ethyl acetate fractions from leaf (Lf-EtOAc) and flower (Fwr-EtOAc) of P. peltatum through the analysis by thin-layer chromatography (T.L.C.), gas chromatography coupled to mass spectrometry (GC-MS), phytochemicals quantification, antioxidant capacity, and antimicrobial activity. After the first round of analysis, it was observed that the FDE-Leaf and FDE-Flower showed higher antioxidant and antimicrobial activities compared to the other FDEs, for which FDE-Leaf and FDE-Flower were fractionated and analyzed in a second round. The antioxidant activity determined by ABTS showed that Lf-EtOAc and Fwr-EtOAc had the lowest IC₅₀ values with 27.15 ± 1.04 and 28.11 ± 1.3 µg/mL, respectively. The content of total polyphenols was 264.57 ± 7.73 for Lf-EtOAc and 105.39 ± 4.04 mg G.A./g FDE for Fwr-EtOAc. Regarding the content of flavonoid, Lf-EtOAc and Fw-EtOAc had the highest concentration with 34.4 ± 1.06 and 29.45 ± 1.09 mg Q.E./g FDE. In addition, the minimum inhibitory concentration (M.I.C.) of antimicrobial activity was evaluated: Lf-EtOAc and Fwr-EtOAc were effective at 31.2 µg/mL for Staphylococcus aureus and 62.5 µg/mL for Salmonella enterica, while for the Enterococcus feacalis strain, Fwr-EtOAc presented 31.2 µg/mL of M.I.C. According to the GC-MS analysis, the main compounds were 1,2,3-Benzenetriol (Pyrogallol), with 77.38% of relative abundance in the Lf-EtOAc and 71.24% in the Fwr-EtOAc, followed by ethyl gallate (13.10%) in the Fwr-EtOAc and (Z)-9-Octadecenamide (13.63% and 6.75%) in both Lf-EtOAc and Fwr-EtOAc, respectively.

Seaweeds are used in traditional agriculture practices because of their beneficial effects. Recently, the rising demand for organically grown foods has amplified the use of organic fertilizers such as seaweed extracts. Despite their beneficial effects, few studies have reported information about compounds in seaweed extracts that are responsible for these benefits. Thus, the aim of this study was to evaluate the potential relationships between the components and secondary metabolites in four seaweed liquid extracts from Eisenia arborea, Macrocystis pyrifera, Padina caulescens, and Sargassum horridum and their biostimulant activity through changes in the germination, growth, and protein content of tomato seedlings (Solanum lycopersicum). The E. arborea and S. horridum extracts showed similar compositions (ash, organic carbon, bicarbonates, and chlorides), minerals (Ca, Fe, and Cu) and secondary metabolites (triterpenes and saponins), albeit with different component concentrations. The chemical composition of the P. caulescens extract was significantly different from those of the other extracts; it was characterized by high levels of total nitrogen, phenols, and carbohydrates. Almost all seaweed extracts had beneficial effects on seed germination and seedling length, except the S. horridum extract that inhibits germination. The hierarchical clustering plots and principal component analysis indicated that germination and protein content are related to the presence of sterol. Shoot length was closely related to mineral levels (K, Zn, B, Na) and the C:N ratio, whereas radicle length was closely related to the content of nitrogen, carbohydrates, phenols, and flavonoids in the seaweed extracts. However, the underlying mechanisms are still unclear and require further studies.

Hydrogels are polymers of great importance due to their multiple applications, which have led to an exponential increase in their production. However, once they have fulfilled their function, they become waste and their ecotoxicological effects are unknown. The aim of the present study was to evaluate the acute toxicity and total antioxidant capacity of the earthworm (Eisenia fetida) exposed to a terpolymeric hydrogel (acrylic acid, acrylamide, and 2-acrylamido-2-methyl-1-propane-sulfonic acid) crosslinked with modified kraft lignin. Four different amounts of hydrogel per unit area were evaluated (0.0924, 0.1848, 0.9242, and 1.848 mg hydrogel/cm²) plus a control, and three replicates were performed for each group. Starting from the amount of 0.1848 mg hydrogel/cm², the earthworms showed physiological and behavioral alterations; at higher amounts, 0.9242 and 1.848 mg hydrogel/cm², more acute signs were observed with mortality rates of 51.7% and 100%, respectively. On the other hand, the antioxidant activity assay showed that the higher the hydrogel exposure amount, the higher the oxidative stress, as evidenced by lower antioxidant activity (67.09% inhibition of the ABTS^●+ radical). Therefore, we concluded that the lignin-modified hydrogel generated oxidative stress and acute lethal toxic effects in Eisenia fetida.

The use of extracts derived from different plants has gained popularity as an alternative option to manage weeds and support phenological development in plants. One of the main problems facing agricultural production is the intensive application of chemical fertilizers that harm the environment. This study investigated the biostimulant effects of the aqueous extracts of Verbesinasphaerocephala and Verbesinafastigiata on the germination and growth of tomato (Solanum lycopersicum) and American cucumber (Cucumis sativus) seedlings. The aqueous extracts of both species of Verbesina were tested at concentrations of 0.5 and 1%. Seed germination and seedling development under nursery conditions were evaluated. The seed germination percentage was reduced in all treatments with the extracts of both Verbesina species when compared to that of the control treatment, which was considered an allelopathic effect. However, seedling growth in pots showed different behavior, with the extracts beneficially affecting certain agronomic variables, such as root and leaf length. The results suggest potential uses for V. sphaerocephala and V. fastigiata extracts, although a greater range of action may be experienced through the effects of certain molecules on weed growth. Additional studies with chemical approaches are necessary to better direct the uses and applications of Verbesina biomolecules, as they also functioned as growth promoters.

In the last decade, interest in the use of seaweed and seaweed-derived products in horticulture has grown due to their great potential as biostimulants for increasing yields and improving food quality in multiple crops. A greenhouse experiment was conducted to investigate the effects of the application of the green seaweed Ulva ohnoi (either as a seaweed suspension [SWS] or seaweed extract [SWE]) on the yield, size, shape, and nutritional quality (i.e., proximate composition and dietary antioxidant content) of tomato fruits (Solanum lycopersicum L. cv. Rio Fuego). A total of 36 tomato plants were potted individually and organized into three experimental groups: SWS (plants drenched with 250 mL of seaweed suspension [2.0%]), SWE (plants drenched with 250 mL of seaweed extract [0.2%]), and control (plants irrigated with water). Each treatment included three replications. The fruits harvested (66%) from SWS-treated plants were produced during the earliest harvest stages. In contrast, the fruits harvested from SWE-treated plants (82%) and control plants (77%) were produced during the late and very late harvest stages. Notably, SWS application significantly enhanced the number of fruits harvested per plant, average fruit weight, yield (kg/plant), number of seeds per fruit, and fruit size. Furthermore, tomato fruits from plants treated with either SWS or SWE exhibited higher percentages of protein, fat, crude fiber, dry matter, and total soluble solids, as well as lower acidity and reduced total carbohydrate content, compared to the control. The antioxidant metabolites in tomatoes, including lycopene, β-carotene, flavonoids, and phenolic acids, increased following the application of SWS and SWE, while anthocyanin and ascorbic acid contents increased only in SWS-treated plants. These results demonstrate that both forms of U. ohnoi application have biostimulating effects on tomato. In particular, the use of SWS shows great potential as a strategy to enhance tomato fruit productivity and quality in sustainable horticultural systems.