Ultrasound-assisted Extraction of Ursolic Acid from the Flowers of Linn (Rubiaceae) and Antiproliferative Activity of Ursolic Acid and Synthesized Derivatives.

Background: Linn (Rubiaceae) is an evergreen shrub with bright scarlet colored flowers found in several tropical and subtropical countries. It is used as an ornamental and medicinal plant. Phytochemical studies revealed that its major special metabolites are triterpene acids, such as ursolic and oleanolic acid.