The luteolin 6-C-(6″-O-trans-caffeoylglucoside) (PN6) isolated from Phyllostachys nigra is effective against both the negative influence of N-methyl-D-aspartate (NMDA) to the rat retina and the oxidative stress induced transformed retinal ganglion cells (RGC-5) death.
The PN6 concentration-dependently inhibited sodium nitroprusside-induced lipid peroxidation. Treatment of the RGC-5 with PN6 decreased the apoptotic proteins of poly (adenosine diphosphate-ribose) polymerase (PARP) and cleaved caspase-3, and increased the antioxidant proteins of superoxide dismutase (SOD)-2, catalase and glutathione peroxidase (GPx-1) expressions by Western blot analysis. The PN6 reduced the thickness of the inner plexiform layer using hematoxylin and eosin staining and decreased the number of terminal deoxynucleotidyl transferase 2′-deoxyuridine 5′-triphosphate nick-end labeling (TUNEL)-positive cells using TUNEL kit assay. Moreover, PN6 attenuated upregulation of apoptotic proteins (PARP and cleaved caspase-3) and downregulation of antioxidant proteins (SOD-2, catalase and GPx-1) caused by NMDA in the rat retina.