Chemical Characterization and Bio-Screening of Neuroprotective Potential of Brazilian Brown Seaweed Canistrocarpus cervicornis in 6-OHDA-Induced Neurotoxicity Model

Brazilian native seaweed Canistrocarpus cervicornis (Ochrophyta, Dictyotaceae) is recognized for its chemodiversity, particularly cyclic diterpenes and polysaccharides, yet its relevance to neurological disorders remains unexplored. This study evaluated the neuroprotective potential of a hydroethanolic extract (ECCH), its polar fraction (CCFPol), a dichloromethane extract (ECCD), and eight derived fractions (CCF1–2, CCF3, CCF4, CCF5–6, CCF7, CCF8–10, and CCF11–15). Cytotoxicity was evaluated in SH-SY5Y neuroblastoma cells, and neuroprotection was examined against 6-OHDA–induced toxicity. The mitochondrial membrane potential, ROS and H2O2 generation assays were conducted to explore the mechanisms underlying the observed effects. Among the key findings, the CCF3 fraction exhibited a high content (75.04%) of dolastane-type diterpenoids. Both CCFPol (100 µg/mL) and CCF3 (1 µg/mL) increased cell viability to 68.43 ± 4.60% and 60.61 ± 0.80%, respectively, compared with 6-OHDA–treated cells (50.70 ± 2.71%). Additionally, CCF3 and CCFPol reduced H2O2 levels (200.0 ± 18.19% and 195.5 ± 16.13%, respectively, vs. 6-OHDA-treated cells: 302.2 ± 17.07%) and lowered intracellular ROS (122.6 ± 22.7% and 129.6 ± 19.4%, respectively, vs. 6-OHDA-treated cells: 153.0 ± 32.7%). This is the first study to demonstrate the neuroprotective potential of the C. cervicornis in a 6-OHDA-induced neurotoxicity cellular model, contributing to the understanding of marine bioactive resources and their relevance for neurological research. Additional studies aimed at isolating the active constituents and clarifying their mechanisms of action will further strengthen and expand the biological relevance of this specie as source of neuroprotective agents.