A yellow to green organic colorant extract from small berries from any shrub of the buckthorn family, such as Rhamnus infectorius, R. amygdalinus, R.oleodies, or R.alaternus. Rhamnetin is a water-soluble colorant composed of the methyl ester of a tri-hydroxyflavonol. It was extracted from the berries for use in textiles, wood stains, and lake pigments. The unripe berries produce a yellow juice used to make Sap green lake. The ripe berries were used to make Dutch pink, a yellow lake.
Physical and Chemical Properties
Soluble in hot water, methanol, acetone.
|mol. wt. = 316.27