Chemical Properties
Roselle is an annual herb native to Africa and is cultivated today in various tropical and subtropical countries. The plant has wedge-shaped, palmate, nervate leaves (the lower leaves, ovate and cleft; the upper ones, acute and dentate) thickening at the top of the branches and bearing a large, axillary, short-petioled flower. The yellow-petaled flowers drop off, leaving protective sepals; these swell into succulent “fruit.” The fruits consist of five-celled capsules containing glabrous, kidney-shaped seeds. The parts used are the fleshy calyxes of flowers, commercially available as dried reddish-brown fragments, approximately 3 to 5 cm (1 to 2 in.) long. Roselle has a pleasant, slightly sour flavor with a faint fruital odor. The fruit has astringent properties.
Physical properties
The infusion is a purple-red liquid with an agreeable, slightly acid taste caused by the presence of tartaric and citric acids. The dark-brown concrete, obtained by petroleum ether extraction, exhibits a faint, fruital odor
