Temporal accumulation of pigments during colour transformation from white to red in Combretum indicum (L.) DeFilipps (syn. Quisqualis indica L.) flowers.

This study focuses on the identification of major anthocyanin following its temporal accumulation in colour changing flowers of Combretum indicum (L.) DeFilipps (syn. Quisqualis indica L.). Separation and identification of pigments governing changes in floral colour were performed using HPLC-DAD. Comparison of chromatographic runs with retention time and UV-Vis spectra of authentic standards determined cyanidin 3-O-glucoside as the major anthocyanin accumulating in the petals. Acid hydrolysis of anthocyanin extracts further confirmed cyanidin as the major anthocyanidin in floral tissue. Light microscopic studies revealed gradual accumulation of pigments in the epidermal and hypodermal cell layers of petals. Antioxidant potentials of floral extracts in ethanol, methanol, water and ethyl acetate were determined by DPPH assay where methanolic extracts showed highest free-radical scavenging capacity, and petals of red stage showed maximum activity. Antioxidative potentials measured in terms of FRAP and ABTS also indicated similar results showing highest activity in the red stage.