Isoquercitrin May Fight Glaucoma

GANGNEUNG, KoreaIsoquercitrin, a fractionated extract of a Chinese cypress shrub, may protect ganglion cells from oxidative damage, possibly preventing progression of glaucoma, according to a new study (Neurochem Int. ePub 2010 Aug 11. DOI: 10.1016/j.neuint.2010.08.005). The shrub known as Thuja orientalis, now classified as Platycladus orientalis, is an evergreen coniferous tree in the cypress family; it is native to northwestern China and has been used extensively as an herbal medicine in Korea and China.

Researchers from Oxford University, England, and the Korea Institute of Science and Technology (KIST), Gangneung, fractionated and purified extracts of the plant to seven compounds: myricitrin, isoquercitrin, hypoletin-7-O-beta-d-xylopyranoside, quercitrin, kaempferin, kaempferol and amentoflavone. While exposure to hydrogen peroxide (H2O2) caused apoptosis in retinal ganglion cells (RGC-5 line), affecting certain proteins linked to cell survival and death, pre-treatment with isoquercitrin prevented apoptosis. The researchers subsequently found isoquercitrin acts as a powerful antioxidant, scavenging radical oxygen species (ROS), while also reducing depletion of the endogenous antioxidants glutathione (GSH) and catalase in RGC-5 cells caused by elevated radical species. They concluded oral consumption of isoquercitrin could reach the retina and help prevent glaucoma, as oxidative stress is thought to play a major role in the demise of retinal ganglion cells.