GC–MS Analysis, Neuropharmacological, and Antidiarrheal Activities of the Acetone Extract of <i>Najas gracillima</i> Seaweed: In Vivo and In Silico Study

Najas gracillima, a marine seaweed found in North America and Asia, was investigated for its neuropharmacological and antidiarrheal properties. Acetone extracts of N. gracillima (ANG) were analyzed using both in vivo and in silico methods. Gas chromatography-mass spectrometry (GC-MS) analysis was conducted to identify bioactive compounds present in the extract. In vivo assessments, including the elevated plus maze, light-dark box, and hole board tests, showed that ANG at doses of 200 and 400 mg/kg exhibited significant (p < 0.001) anxiolytic effects. Both doses also demonstrated antidepressant effects in the forced swimming and tail suspension tests by significantly (p < 0.001) reducing immobility time, with the 200 mg/kg dose showing more pronounced effects. Sedative activity was confirmed through open field and hole cross tests, where both doses exhibited significant (p < 0.001) sedative effects. ANG also demonstrated significant antidiarrheal effects at 400 mg/kg in castor oil-induced diarrhea (p < 0.05) and gastrointestinal motility tests (p < 0.01). Molecular docking simulations revealed that compounds from ANG had strong binding affinities to critical drug targets involved in anxiety, depression, sleep disorders, and diarrhea. These findings suggest that N. gracillima holds potential for therapeutic use in treating neuropharmacological disorders and diarrhea, warranting further investigation.