The content of zeaxanthin in Gou Qi Zi, a potential health benefit to improve visual acuity

Gou Qi Zi was obtained from 6 different sources. The specimens were homogenised in water-ethanol followed by extraction with hexane. Total carotenoid content in the hexane extract was estimated by the absorbance at 450 nm. Chromatography on a silica column eluted by dioxane-hexane showed only 1 carotenoid peak which was converted to zeaxanthin upon hydrolysis. The zeaxanthin concentrations should be useful as an objective parameter for grading of Gou Qi Zi.