Studies on the flavonoids from the flowers of Hylocereus undatus

Objective: To study the chemical constituents of the flowers of Hylocereus undatus.

Methods: The constituents were isolated and purified by various modern chromatographic techniques. The structures of the compounds were elucidated based on their physicochemical properties and spectral analyses.

Results: Thirteen compounds were isolated from the flowers of H. undatus. Their structures were elucidated as kaempferol (1), quercetin (2), isorhamnetin (3), kaempferol 3-O-alpha-L-arabinfuranoside (4), kaempferol 3-O-beta-D-glucopyranoside (5), quercetin 3-O-beta-D-glucopyranoside (6), isorhamnetin 3-O-beta-D-glucopyranoside (7), kaempferol 3-O-beta-D-galactopyranoside (8), quercetin 3-O-beta-D-galactopyranoside (9), kaempferol 3-O-beta-D-rutinoside (10), isorhamnetin 3-O-beta-D-rutinoside (11), kaempferol 3-O-alpha-L-rhamopyranosyl-(1 --> 6)-beta-D-galactopyranoside (12), and isorhamnetin 3-O-alpha-L-rhamopyranosyl-(1 --> 6)-beta-D-galactopyranoside (13).

Conclusions: All the compounds are isolated from this plant for the first time.