Flavonol derivatives of Desmanthodium (compositae)

The flavonoids of three species of Desmanthodium are based upon kaempferol, quercetin and quercetagetin. Sugar substitutions comprise glucosides, galactosides, rhamnosides, rutinosides and diglucosides. Four different O-methylated compounds occur in field populations of the genus, but they are found in all species and are therefore not useful for sectional or subgeneric delimitations. The flavonoid profile of Desmanthodium is very similar to that of Clibadium, which parallels their close morphological affinity.     

Flavonol derivatives of the genus Clibadium (compositae)

The flavonoids of eleven species of Clibadium are all based on the flavonols kaempferol, quercetin and quercetagetin. Glucose and galactose sugar substitutions occur in all taxa, while rhamnosides, arabinosides, xylosides, rutinosides and diglucosides are less widely distributed. O-Methylated compounds provide the most meaningful taxonomic information and serve to divide the species into two groups. Infraspecific variation of flavonoids is commonplace. This is the first report of flavonoids in Clibadium.     

Further studies of flavonols of Clibadium (compositae)

The flavonoids of an additional eight species of Clibadium have been determined. The compounds are derivatives of kaempferol, quercetin and quercetagetin. O-Methylated quercetagetin derivatives were found in several taxa with the possibility that 6-methoxykaempferol may also exist in one collection. Kaempferol and quercetin exist as 3-O-glucosides, galactosides, rhamnosides, rutinosides and diglucosides although not all glycosides occur in each taxon. Quercetagetin derivatives occur as 7-O-glucosides. Observations on these newly investigated species confirm previous work in the genus that three types of flavonoid profiles exist: (1) kaempferol and quercetin 3-glycosides; (2) kaempferol and quercetin 3-glycosides plus quercetagetin 7-glucoside; and (3) kaempferol and quercetin 3-glycosides plus quercetagetin 7-glucoside and O-methylated derivatives of quercetagetin.     

Flavonol derivatives of Ichthyothere terminalis

The flavonoids of Ichthyothere terminalis are based upon quercetin, with minor amounts of kaempferol and dihydroquercetin. All glycosides are linked at position-3. Quercetin 3-glucoside, 3-galactoside, and 3-arabinoside comprise the monoglycoside fraction. The diglycoside fraction consists of quercetin 3-rutinoside, 3-rhamnosylgalactoside and 3-digalactoside. The single triglycoside present was shown to be quereetin 3-rhamnosylgalactosylgalactoside. A major constituent of the aglycone fraction was shown to be 3-0-methylquercetin. The flavonoid profile of Ichthyothere terminalis shows marked ditterences from those of the related genera Clibadium and Desmanthodium.