Marine macroalgae (commonly known as seaweeds), a rich yet underexplored resource, have emerged as a promising source of bioactive compounds with potent antioxidant properties. While oxidative stress is a critical factor in the pathogenesis of numerous chronic diseases, including neurodegenerative disorders, cardiovascular conditions, and cancer, macroalgae-derived compounds such as polyphenols, carotenoids, peptides, and sulfated polysaccharides have demonstrated the ability to mitigate oxidative damage through multifaceted mechanisms. These compounds neutralize reactive oxygen species and modulate key cellular pathways involved in inflammation and apoptosis. Despite significant advancements, gaps persist in understanding the pharmacokinetics, bioavailability, and clinical applications of these bioactives. Additionally, the inefficiencies of traditional extraction methods call for adopting innovative, environmentally friendly techniques that preserve bioactivity. This review synthesizes current knowledge on the therapeutic potential of macroalgal bioactives, acknowledges the contributions of other marine algae where relevant, highlights challenges in their extraction, and proposes future directions for research and application.

Breast cancer is the leading cause of death in women worldwide. The search for novel compounds with antitumor activity, with less adverse effects and higher efficacy, and the development of methods to evaluate their toxicity is an area of ​​intense research. In this study we implemented the preparation and culture of breast tumor explants, which were obtained from precision-cut breast tumor slices. In order to validate the model we are proposing to screen antineoplastic effect of natural compounds, we selected caffeic acid, ursolic acid, and rosmarinic acid. Using the Krumdieck tissue slicer, precision-cut tissue slices were prepared from breast cancer samples; from these slices, 4 mm explants were obtained and incubated with the selected compounds. Viability was assessed by Alamar Blue assay, LDH release, and histopathological criteria. Results showed that the viability of the explants cultured in the presence of paclitaxel (positive control) decreased significantly (P<0.05); however, tumor samples responded differently to each compound. When the explants were coincubated with paclitaxel and compounds, a synergic effect was observed. This study shows thatex vivoculture of breast cancer explants offers a suitable alternative model for evaluating natural or synthetic compounds with antitumor properties within the complex microenvironment of the tumor.

Seven medicinal plants from Chiapas, Mexico, used by Native Americans were analyzed, aiming to improve the understanding of their medicinal properties through the evaluation of various biological activities, i.e., bactericidal, antioxidant, α-glucosidase inhibition, and toxicity, to provide a scientific basis for the management of infectious and hyperglycemic diseases in the Mexican southeast. Plant extracts were obtained from Cordia dodecandra, Gaultheria odorata, Heliotropium angiospermum, Justicia spicigera, Leucaena collinsii spp. collinsii, Tagetes nelsonii, and Talisia oliviformis through maceration techniques using methanol and chloroform (1:1). Minimum Inhibitory Concentration (MIC) was employed to determine the antibacterial activity against Staphylococcus aureus, Enterobacter faecalis, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, and Pseudomonas aeuroginosa. The antiradical/antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays and antihemolytic activity using the 2,2’-Azobis(2-amidinopropane) dihydrochloride radical (APPH). The anti-α-glucosidase activity was evaluated in vitro through the chromogenic PNPG assay. The toxicity was assessed using the brine shrimp lethality assay. The highest antimicrobial activity was displayed by T. nelsonii, mainly against E. faecalis and P. aeuroginosa. The extracts of L. collinsii, J. spicigera, and T. nelsonii possess antioxidant properties with EC₅₀ < 50 μg/mL. J. spicigera and T. nelsonii extracts showed the highest antihemolytic activity with IC₅₀ < 14 μg/mL. T. nelsonii exhibited a remarkable inhibitor effect on the α-glucosidase enzyme and the greatest toxic effect on Artemia salina with IC₅₀ = 193 ± 20 μg/mL and LD₅₀ = 14 ± 1 μg/mL, respectively. According to our results, G. odorata, J. spicigera, T. nelsonii, and T. oliviformis extracts contained active antimicrobial compounds. At the same time, T. nelsonii stands to be a possible source of effective antineoplastic and antihyperglycemic compounds.

Focused on our interest to develop novel antiparasistic agents, the present study was aimed to evaluate the biological activity of an extract of Laurencia johnstonii collected in Baja California Sur, Mexico, against an Acantamoeba castellanii Neff strain. Bioassay-guided fractionation allowed us to identify the amoebicidal diastereoisomers α-bromocuparane (4) and α-isobromocuparane (5). Furthermore, bromination of the inactive laurinterol (1) and isolaurinterol (2) yielded four halogenated derivatives, (6)–(9), which improved the activity of the natural sesquiterpenes. Among them, the most active compound was 3α-bromojohnstane (7), a sesquiterpene derivative which possesses a novel carbon skeleton johnstane.