Anthocyanins of Gladiolus cultivars and their contribution to flower colors

Abstract

Eleven anthocyanins were isolated from the flowers of 6 selected cultivars and identified as 3-O-rutinoside-5-O-glucosides of cyanidin, malvidin, pelargonidin and peonidin, and 3,5-di-O-glucosides of petunidin, malvidin, pelargonidin, cyanidin and peonidin, and pelargonidin 3-O-rutinoside and malvidin 3-O-glucoside, by thin layer chromatography (TLC), liquid chromatograph-mass spectrometry (LC-MS) and high performance liquid chromatography (HPLC) comparisons with authentic specimens. Of these anthocyanins, the first 4 and pelargonidin 3-O-rutinoside have previously been characterized as 3-O-rhamnosylglucoside-5-O-glucoside and 3-O- rhamnosylglucoside. In this survey, they were clearly identified as 3-O-rutinoside-5-O-glucoside and 3-O-rutinoside, for the first time. Anthocyanin composition in the flowers of 84 Gladiolus cultivars was surveyed by HPLC and divided into 18 groups (Groups 1-18) according to the anthocyanin pattern. Of these cultivars, 82 were first surveyed for anthocyanins, except 'Blue Isle' and 'True Love'. The relationship between anthocyanin content and flower colors was discussed. Major anthocyanins of purple flowers were malvidin glycosides together with petunidin 3,5-di-O-glucoside as a minor component, but delphinidin glycoside was not detectable. Red flowers are due to pelargonidin glycosides. Though pink flowers consist of various anthocyanins, pelargonidin, cyanidin, peonidin, petunidin and malvidin glycosides, they were comparatively scarce compared with those of purple and red flowers. In many cases, anthocyanins were not detected from yellow and white flowers; however, a few yellow and white cultivars contained an extremely small amount of anthocyanins. Such cultivars had a colored spot or streak on the perianth, so their anthocyanins were detected by HPLC surveys. JSHS © 2008.