Persimmon (Diospyros kaki Thunb.) leaves are used as a traditional folk medicine in Korea and considered to
have various health benefits. We investigated the effect of ethanol extract of D. kaki (EEDK) on an animal model of retinal degeneration (RD), a leading cause of photoreceptor
cell death resulting in blindness. In a RD mice model, in which retinal damage was
indued by intraperitoneal injection of N-methyl-N-nitrosourea (MNU) (50 mg/kg), a DNA-methylating agent that causes photoreceptor damage.
Various concentrations of EEDK were daily administered, orally, for 1, 2, and 4 weeks
after MNU injection. EEDK markedly reduced up-regulation of glial fibrillary acidic
protein (GFAP) and inhibited up-regulation of cleaved caspase-8. Moreover EEDK up-regulated
rhodopsin against RD. Morphologically, the outer nuclear layer, where photoreceptors
reside, was well preserved in the EEDK-treated mice retinas throughout the experimental
period. To standardize EEDK, we performed chromatographic analysis and identified
8 flavonoids as marker compounds using spectroscopic methods. These results demonstrate
that EEDK has protective effects against MNU-induced retinal damage, and may be considered
as an agent for treating or preventing retinal degeneration.
Keywords: Diospyros kaki, MNU, N-methyl-N-nitrosourea, retinal degeneration
