Bioactive Zoochemicals From Portunus sanguinolentus Shells: A Sustainable Source of Acetylcholinesterase Inhibitors and Antimicrobial Agents.

This study explores the therapeutic potential of methanol extracts from the shells of the marine crab Portunus sanguinolentus, with a focus on inhibiting acetylcholinesterase (AChE) to enhance acetylcholine (ACh) levels, an essential strategy in the management of Alzheimer's disease (AD). GC-MS analysis identified 18 distinct zoochemicals, predominantly fatty acid derivatives, and HPLC analysis confirmed the presence of n-Hexadecanoic acid, while FT-IR spectroscopy confirmed the presence of functional groups typical of polyphenols, alkaloids, and terpenoids. The extract exhibited notable antioxidant activity, with IC50 values of 62.08 µg/mL (DPPH) and 68.05 µg/mL (ABTS), both showing strong dose-dependent responses (R2 = 0.90). AChE inhibition assays revealed dose-dependent effects with an IC50 of 161.49 µg/mL (R2 = 0.943). Molecular docking studies further supported the bioactivity, indicating strong interactions between identified zoochemicals and key targets, including AChE (1EVE), Peroxiredoxin 5 (1HD2), Myeloperoxidase (1DNU), and MraY (5CKR). Additionally, the extract demonstrated significant antibacterial efficacy, confirmed through MIC, MBC, zone of inhibition assays, cytoplasmic leakage (DNA and protein), and in silico predictions. These findings suggest that the P. sanguinolentus shell methanol extract contains bioactive zoochemicals with promising AChE-inhibitory, antioxidant, and antibacterial activities. Importantly, the use of crab shells not only contribute to drug development for Alzheimer's disease but also offers a sustainable approach to marine biowaste valorization.