Flavonol glycosides in the flowers of the Himalayan Meconopsis paniculata and Meconopsis integrifolia as yellow pigments
2018
Two flavonol glycosides were isolated from the yellow flowers of Bhutani Himalayan Meconopsis paniculata, together with other two minor flavonol glycosides. They were identified as 6-hydroxykaempferol 3-O-glucoside and 6-hydroxykaempferol 3-O-sophoroside by UV, LC-MS, acid hydrolysis and 1H and 13C NMR. Two minor flavonol glycosides were identified as kaempferol 3-O-glucoside and kaempferol 3-O-sophoroside. Although herbacetin (8-hydroxykaempferol) 3-O-glucoside has been reported from M. paniculata as a yellow pigment by Harborne (1969), 6-hydroxykaempferol 3-O-glucoside and 3-O-sophoroside were found in this survey. The latter flavonoid was reported in nature for the first time. On the other hand, four flavonol glycosides were isolated from the yellow flowers of M. integrifolia and characterized as quercetin 3-O-gentiobioside and three 3-O-(acetylgentiobiosides). Thus, it was proved that the yellow flower colour of two Meconopsis species, M. paniculata and M. integrifolia, are due to flavonol glycosides.
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