Monica Jordheim

Identification of cyanidin 3-O-β-(6″-(3-hydroxy-3-methylglutaroyl)glucoside) and other anthocyanins from wild and cultivated blackberries.

Anthocyanins from blackberries are natural dietary pigments. The aim of this study was to investigate the occurrence of anthocyanins in fruits of wild Norwegian blackberries and three blackberry ( Rubus fruticosus L.) cultivars and to report the complete identification of cyanidin 3-O-β-(6″-(3-hydroxy-3-methylglutaroyl)glucopyranoside), 5. This new pigment is most probably the same pigment that has previously been reported to occur in various blackberry samples as cyanidin 3-dioxalylglucoside. All of the examined blackberry samples contained in similar relative proportions the 3-glucoside (1), 3-rutinoside (2), 3-xyloside (3), and 3-O-β-(6″-malonylglucoside) (4) of cyanidin and 5. The absolute amounts of 1-5 in the wild Norwegian blackberries were 249, 18, 10, 24, and 22 mg of cyanidin 3-glucoside equivalents/100 g of fresh weight, respectively.

Chemistry of Flavonoid-Based Colors in Plants

This chapter reviews plant pigmentation on the basis of flavonoid chemistry of anthocyanins, chalcones, and aurones reported in recent years. Various structural elements that influence anthocyanin coloration are described in detail. Figures illustrate copigmentation mechanisms. Reports on the anthocyanin content in blue flowers, fruits, and vegetables in the human diet, and molar absorptivity values are compiled. Anthocyanin localization in plant tissue and their production in plant cultures by microorganisms are discussed. A short review of flavonoid biosynthesis is included, and various functions of anthocyanins and other flavonoid pigments in plants are discussed.

Purple anthocyanin colouration on lower (abaxial) leaf surface of Hemigraphis colorata (Acanthaceae)

Graphical abstract Purple abaxial colouration of leaves of Hemigraphis colorata (Acanthaceae) is caused by two unusual anthocyanins.

Characterization of Polyphenolic Content in the Aquatic Plants Ruppia cirrhosa and Ruppia maritima —A Source of Nutritional Natural Products

Herein, the polyphenolic content in extracts of Ruppia cirrhosa (Petagna) Grande and Ruppia maritima L.was fully characterized for the first time. High amounts of the main compound chicoric acid (CA) (≤30.2 ± 4.3 mg/g) were found in both Ruppia species. In addition, eight flavonoids, namely the 3-O-glucopyranosides and 3-O-galactopyranosides, as well as malonylated 3-O-glycosides of quercetin and isorhamnetin, were isolated and identified. The antioxidant activity of Ruppia cirrhosa extracts and isolated compounds was investigated spectrophotometrically by a 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radical scavenging assay. IC50 values were 31.8–175.7 μg/mL for Ruppia cirrhosa extracts and 12.1–88.4 μg/mL for isolated flavonoids. Both individual and total phenolic and flavonoid content were quantified in crude extracts using analytical HPLC. The relative high amount of total flavonoids ranged from 5.9 to 14.7 mg/g in both species, with concentrations of individual flavonoids ranging from 0.4 to 2.9 mg/g dry weight. The content of chicoric acid was twofold more in Ruppia maritima than in Ruppia cirrhosa. Seasonal variation of the quantitative content in Ruppia cirrhosa was examined. Total flavonoid content ranged from 8.4 mg/g in October to 14.7 mg/g in August, whereas the highest concentration of chicoric acid was observed in March (29.2 mg/g).