Flavonoids from the flowers of Adenium obesum (Forssk.) Roem. & Schult., Mandevilla sanderi (Hemsl.) Woodson, and Nerium oleander L. (Apocynaceae)

Abstract

Twenty-two ornamental flowers from different Adenium obesum, Mandevilla sanderi, and Nerium oleander cultivars/seedlings were analyzed for the presence of anthocyanins, flavonols, and chlorogenic acid using nuclear magnetic resonance (NMR) and mass spectrometry (MS). Cyanidin 3-O-[6-O-(rhamnosyl)-galactoside] and cyanidin 3-O-(galactoside) were identified as the major and minor anthocyanins, respectively, in three A. obesum seedlings that had red and red-purple flowers.Cyanidin 3-O-[2-O-(xylosyl)-galactoside] was identified as the major anthocyanin, whereas cyanidin 3-O-[6-O-(rhamnosyl)-galactoside] and cyanidin 3-O-(galactoside) were identified as the minor anthocyanins in 8 M. sanderi cultivars that had red and red-purple flowers. Cyanidin 3-O-[6-O-(rhamnosyl)-galactoside] and cyanidin 3-O-(galactoside) were identified as the major anthocyanins, whereas cyanidin 3-O-[2-O-(xylosyl)-galactoside] was identified as the minor anthocyanin in 8 N. oleander cultivars with red and red-purple flowers. Low levels of anthocyanins were detected in the N. oleander and M. sanderi cultivars that had white flowers, and there were no anthocyanins detected in the N. oleander cultivars with yellow flowers. Chlorogenic acid and four flavonols, quercetin 3-O-[6-O-(rhamnosyl)-galactoside], quercetin 3-O-[6-O-(rhamnosyl)-glucoside], kaempferol 3-O-(galactoside), and kaempferol 3-O-[6-O-(rhamnosyl)-galactoside], were identified in the flowers from all 22 cultivars/seedlings investigated.