Background:Cenostigma bracteosum (Tul.) Gagnon & G.P. Lewis (Fabaceae), popularly known as “catingueira”, is a plant widely distributed in the Caatinga biome, which comprises 11% of the Brazilian territory. While this species is of interest given local knowledge, formal reports are lacking in the literature, warranting targeted investigation. This study aimed to prepare and characterize a hydroethanolic extract of C. bracteosum leaves, prepare carbopol gels containing the extract, and evaluate their cytotoxicity and antibacterial activity against Staphylococcus aureus and Escherichia coli. Methods: The initial extract was prepared in an ultrasonic bath using ethanol/water (70:30, v/v). The extract (1 mg/mL) was analyzed by liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS). Carbopol-based gels containing 1% and 3% of C. bracteosum extract were prepared and characterized in terms of pH, conductivity, spreadability, and rheology. The cytotoxicity was determined by the MTT method using MC3T3-E1 pre-osteoblast cells and L929-CCL1 fibroblast cells. The antibacterial activity of the extract and gels was evaluated using the agar diffusion method against S. aureus and E. coli. Results: The C. bracteosum leaves extract demonstrated antibacterial activity against S. aureus and E. coli, were not cytotoxic for the assessed cells at concentrations up to 100 μg/mL, and its analysis by UHPLC-MS/MS allowed the annotation of 18 metabolites, mainly of the phenolic acid and flavonoids glycoside classes, together with a biflavonoid. The prepared gels remained stable over the 30-day post-production analysis period. Conclusions: These findings provide a better understanding of the chemical diversity of the secondary metabolites of a common Caatinga biome species—C. bracteosum—specifically present in leaves hydroethanolic extract and gel formulation adapted for skin application with activity against S. aureus.

As the global demand for eco-friendly food ingredients grows, marine macroalgae emerge as a valuable resource for multiple applications using a circular bioeconomy approach. In this study, green macroalgae Ulva flexuosa, naturally accumulated in aquaculture ponds as a residual biomass (by-product) of shrimp and oyster farming, were investigated regarding their bioactivity, chemical composition, and antioxidant properties. The use of aquaculture by-products as raw materials not only reduces waste accumulation but also makes better use of natural resources and adds value to underutilized biomass, contributing to sustainable production systems. For this, a comprehensive approach including the evaluation of its composition and environmentally friendly extraction of bioactive compounds was conducted and discussed. Green macroalgae exhibited high fiber (37.63% dry weight, DW) and mineral (30.45% DW) contents. Among the identified compounds, palmitic acid and linoleic acid (ω-6) were identified in the highest concentrations. Pigment analysis revealed a high concentration of chlorophylls (73.95 mg/g) and carotenoids (17.75 mg/g). To evaluate the bioactivity of Ulva flexuosa, ultrasound-assisted solid–liquid extraction was performed using water, ethanol, and methanol. Methanolic extracts showed the highest flavonoid content (59.33 mg QE/100 g), while aqueous extracts had the highest total phenolic content (41.50 mg GAE/100 g). Ethanolic and methanolic extracts had the most potent DPPH scavenging activity, whereas aqueous and ethanolic extracts performed best at the ABTS assay. Overall, we show the upcycling of Ulva flexuosa, an underexplored aquaculture by-product, as a sustainable and sensible strategy for multiple value-added applications.

This study investigated the analgesic, anti‐inflammatory, and antiulcer activities of thioxo‐thiazolidinone derivatives ( 2a , 2b , and 2c ) and synthesized from glycine, alanine, and phenylalanine. Male Wistar rats (240–290 g; n = 5/group) and Swiss mice (25–35 g; n = 6/group) were used for anti‐inflammatory and analgesic tests, respectively, under approved ethical protocol (CEUA/UFRN n ° 004/2012) and following the ARRIVE and 3 Rs guidelines. Analgesic activity was assessed using the hot plate and acetic acid‐induced writhing tests; anti‐inflammatory effects were evaluated in carrageenan‐induced paw edema and peritonitis models; and antiulcer potential was tested against indomethacin‐induced gastric lesions. In the rat paw edema model, Compound 2c (200 mg/kg, p.o.) and sodium diclofenac reduced edema. In the peritonitis model, Compound 2c decreased the number of leukocytes ( p < 0.05), similar to indomethacin ( p < 0.05). In the hot plate test, Compound 2c (200 mg/kg) produced significant antinociceptive effects at 30, 90, and 120 min ( p < 0.05), partially reversed by naloxone, suggesting opioid involvement. Compounds 2a (50 mg/kg:, p < 0.01) and 2b (50 mg/kg:; 100 mg/kg: p < 0.05) and indomethacin at a dose of 10 mg/kg ( p < 0.05) significantly reduced writhing responses comparable to control. Unlike indomethacin (ulcer score: 63.4 ± 5.2), all compounds showed minimal gastric damage (scores ≤ 8.1 ± 1.3, p < 0.001). In silico analysis revealed that 2c exhibited strong binding affinities to PLA2 (−10.38 kcal/mol) and ADA (−9.78 kcal/mol), supporting its pharmacological profile. Together, these quantitative and comparative findings demonstrate that 2c exhibits potent analgesic and anti‐inflammatory activities with markedly reduced gastric toxicity, reinforcing its potential as a safe multitarget anti‐inflammatory candidate.