Black bamboo, Phyllostachys nigra, attenuates retinal degeneration caused by oxidative stress in vitro and in vivo

Abstract

In order to find the neuroprotective compounds from the leaves of Phyllostachys nigra (P. nigra), we investigated the protective effect on the negative influence of oxidative stress such as l-buthionine-(S,R)-sulfoximine (BSO) with glutamate or hydrogen peroxide (H2O2). Ethyl acetate fraction showed a significant higher inhibition both of negative insults, and eight compounds were isolated using preparative RP-HPLC and Sephadex LH-20 column chromatography. Among them, only luteolin 6-C-(6″ O-trans-caffeoylglucoside) (compound 6) was found to possess strongly protection both insults of BSO with glutamate or H2O2. Treatment of the RGC-5 cells with PN reduced the reactive oxygen species and recovered glutathione ratio caused by various radical species such as H2O2, OH▪ or O2▪-. Moreover, PN showed potent protective effect of against lipid peroxidation. NMDA to the retina affected the thickness of inner plexiform layer (IPL) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) positive cells in ganglion cell layer (GCL). Importantly, the thinning of IPL and increased TUNEL positive cells were attenuated by P. nigra . In conclusion, PN has neuroprotective effects against retinal damage both in vitro and in vivo, and compound 6 isolated from P. nigra could possibly be acting compounds due to its anti-oxidative properties.