In vitro evaluation of the neuroprotective effect of oligo-porphyran from Porphyra yezoensis in PC12 cells

Porphyran, derived from the marine red algae Porphyra and Pyropia, is a type of polysaccharide. Oligo-porphyran (OP) was prepared from porphyran (isolated from Pyropia yezoensis) through the acidolysis reaction containing a linear backbone of alternating 3-linked beta-d-galactose and 4-linked alpha-l-galactose-6-sulfate. Our previous studies have shown that oligo-porphyran could attenuate MPTP-induced behavioral deficits in mice by inhibiting the tyrosine hydroxylase (TH) loss. In the present study, we further investigated how OP protects the dopamine neurons from loss in PC12 cells. OP significantly attenuated LDH release and the production of reactive oxygen species (ROS) lesioned by 6-OHDA. Moreover, OP alleviated the mitochondrial membrane potential (MMP) loss, the ratio of Bax/Bcl-2, and upregulated the PI3K/ Akt/PKC pathway, the level of tyrosine hydroxylase (TH), and dopamine transporter (DAT). Furthermore, OP decreased the production of proinflammatory cytokines. Terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) staining further indicated that OP treatment inhibited apoptosis. These results might contribute to the overall understanding of the potential health benefits of OP for food and drug applications.