Characterization of Acylated Anthocyanins in Callus Induced From Storage Root of Purple-Fleshed Sweet Potato, Ipomoea batatas L.

Four anthocyanins were isolated from a highly pigmented callus induced from the storage root of purple-fleshed sweet potato (Ipomoea batatas L) cultivar Ayamurasaki. The anthocyanins were respectively identified as cyanidin 3- $O$ -(2- $O$ -(6- $O$ -( $E$ )-caffeoyl- $\beta$ -D-glucopyranosyl)- $\beta$ -D-glucopyranoside)-5- $O$ - $\beta$ -D-glucopyranoside, cyanidin 3- $O$ -(2- $O$ -(6- $O$ -( $E$ )- $p$ -coumaroyl- $\beta$ -D-glucopyranosyl)-6- $O$ -( $E$ )-caffeoyl- $\beta$ -D-glucopyranoside)-5- $O$ - $\beta$ -D-glucopyranoside, cyanidin 3- $O$ -(2- $O$ -(6- $O$ -( $E$ )- $p$ -coumaroyl- $\beta$ -D-glucopyranosyl)-6- $O$ -( $E$ )- $p$ -coumaroyl- $\beta$ -D-glucopyranoside)-5- $O$ - $\beta$ -D-glucopyranoside, and peonidin 3- $O$ -(2- $O$ -(6- $O$ -( $E$ )- $p$ -coumaroyl- $\beta$ -D-glucopyranosyl)-6- $O$ -( $E$ )- $p$ -coumaroyl- $\beta$ -D-glucopyranoside)-5- $O$ - $\beta$ -D-glucopyranoside by chemical and spectroscopic analyses. These anthocyanins were examined with respect to the stability in neutral aqueous solution as well as the radical scavenging activity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. These acylated anthocyanins exhibited both higher stability and higher DPPH radical scavenging activity than corresponding nonacylated cyanidin and peonidin 3- $O$ -sophoroside-5- $O$ -glucosides.

Acylated anthocyanidin 3-sophoroside-5-glucosides from Ajuga reptans flowers and the corresponding cell cultures.

Four anthocyanins from Ajuga reptans flowers and its cell cultures were isolated, and a fifth was also characterized by HPLC-mass spectrometry. By means of chemical and spectroscopic analyses, their structures were identified as delphinidin 3-(p-coumaroyl-feruloyl)sophoroside-5-malonylglucoside, delphinidin 3-(diferuloyl)sophoroside-5-malonylglucoside, and cyanidin 3-(di-p-coumaroyl)sophoroside-5-glucoside, respectively. The other two were tentatively identified as delphinidin 3-(diferuloyl)sophoroside-5-glucoside and cyanidin 3-(feruloyl-p-coumaroyl)sophoroside-5-malonylglucoside. In neutral aqueous solution, the crude extract from A. reptans flower cell cultures and the major anthocyanin cyanidin 3-(di-p-coumaroyl)sophoroside-5-malonylglucoside were more stable than cyanidin 3-glucoside, and also prevented more efficiently peroxidation than did the latter. A. reptans flower cell culture anthocyanins may have a potential as natural colorants for food utilities or other purposes.

alpha-Glucosidase inhibitory action of natural acylated anthocyanins. 1. Survey of natural pigments with potent inhibitory activity.

alpha-Glucosidase (AGH) inhibitory study by natural anthocyanin extracts was done. As the result of a free AGH assay system, 12 anthocyanin extracts were found to have a potent AGH inhibitory activity; in particular, Pharbitis nil (SOA) extract showed the strongest maltase inhibitory activity, with an IC(50) value of 0.35 mg/mL, as great as that of Ipomoea batatas (YGM) extract (IC(50) = 0.36 mg/mL). Interestingly, neither extract inhibited the sucrase activity at all. For the immobilized assay system, which may reflect the pharmacokinetics of AGH at the small intestine, SOA and YGM extracts gave more potent maltase inhibitory activities than those of the free AGH assay, with IC(50) values of 0.17 and 0.26 mg/mL, respectively. Both extracts also inhibited alpha-amylase action, indicating that anthocyanins would have a potential function to suppress the increase in postprandial glucose level from starch.

alpha-Glucosidase inhibitory action of natural acylated anthocyanins. 2. alpha-Glucosidase inhibition by isolated acylated anthocyanins.

Four diacylated pelargonidin (Pg: SOA-4 and SOA-6), cyanidin (Cy: YGM-3), and peonidin (Pn: YGM-6) 3-sophoroside-5-glucosides isolated from the red flowers of the morning glory, Pharbitis nil cv. Scarlett O'Hara (SOA), and the storage roots of purple sweet potato, Ipomoea batatas cv. Ayamurasaki (YGM), were subjected to an alpha-glucosidase (AGH) inhibitory assay, in which the assay was performed with the immobilized AGH (iAGH) system to mimic the membrane-bound AGH at the small intestine. As a result, the acylated anthocyanins showed strong maltase inhibitory activities with IC(50) values of <200 microM, whereas no sucrase inhibition was observed. Of these, SOA-4 [Pg 3-O-(2-O-(6-O-(E-3-O-(beta-D-glucopyranosyl)caffeyl)-beta-D-glucopyranosyl)-6-O-E-caffeyl-beta-D-glucopyranoside)-5-O-beta-D-glucopyranoside] possessed the most potent maltase inhibitory activity (IC(50) = 60 microM). As a result of a marked reduction of iAGH inhibitory activity by deacylating the anthocyanins, that is, Pg (or Cy or Pn) sophoroside-5-glucoside, acylation of anthocyanin with caffeic (Caf) or ferulic (Fer) acid was found to be important in the expression of iAGH (maltase) inhibition. In addition, the result that Pg-based anthocyanins showed the most potent maltase inhibition, with an IC(50) value of 4.6 mM, and the effect being in the descending order of potency of Pg > Pn/Cy strongly suggested that no replacement at the 3'(5')-position of the aglycon B-ring may be essential for inhibiting iAGH action.

Anthocyanins from red flower tea (Benibana-cha), Camellia sinensis.

Three anthocyanins were isolated from the leaves of red flower tea (Benibana-cha), Camellia sinensis, and their structures were determined by means of chemical and spectroscopic analyses. Two are the anthocyanins, delphinidin and cyanidin 3-O-beta-D-galactosides, respectively. Whereas the third, delphinidin 3-0-beta-D-(6-(E)-p-coumaryl)galactopyranoside. The anthocyanins were also contained in the flowers of Benibana-cha in different compositions.

Activity of anthocyanins from fruit extract of Ribes nigrum L. against influenza A and B viruses.

Earlier, we have detected antiviral activity in an extract from Ribes nigrum L. fruits ("Kurokarin", name of the one species of black currant in Japanese) against influenza A and B viruses, and herpes simplex virus 1 (Knox et al., Food Processing 33, 21-23, 1998). In the present study, the antiviral activity of constituents of a Kurokarin extract and the mechanism of its antiviral action were examined. Kurokarin extracts were separated to fractions A to D by column chromatography. The major constituents of the fraction D were estimated as anthocyanins. The fraction D was further fractionated by thin-layer chromatography (TLC) to fractions A' to G'. The fraction E' consisted of 3-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranosyl-cyanidin and 3-O-beta-D-glucopyranosyl-cyanidin, and the fraction F' consisted of 3-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranosyl-delphinidin and 3-O-beta-D-glucopyranosyl-delphinidin, identified by high performance liquid chromatography (HPLC) with standards and by high resolution mass spectrometry. The fractions D' to G' showed potent antiviral activity against influenza viruses A and B. The additive antiviral effect of a combination of the fractions E' and F' was assessed. Anthocyanins in the fraction F' did not directly inactivate influenza viruses A and B, but they inhibited virus adsorption to cells and also virus release from infected cells.

Anthocyanins in callus induced from purple storage root of Ipomoea batatas L.

Two anthocyanins were isolated from the highly pigmented callus derived from the storage root of purple sweet potato (Ipomoea batatas L.) cultivar 'Ayamurasaki'. One was identified as cyanidin 3-O-sophoroside-5-O-glucoside, and the other as cyanidin 3-O-(2-O-(6-O-(E)-p-coumaroyl-beta-D-glucopyranosyl)-beta-D-glucop yranoside)-5-O-beta-D-glucopyranoside, by chemical and spectroscopic analysis.

New anthocyanins from purple pods of pea (Pisum spp.).

Two new anthocyanins were isolated from purple pods of pea (Pisum spp.). Their structures were identified as delphinidin 3-xylosylgalactoside-5-acetylglucoside and its deacetylated derivative by the usual chemical degradation methods and by spectroscopic methods such as UV-VIS, MS and NMR. Both pigments showed moderate stability and antioxidative activity in a neutral aqueous solution.

Establishment and characteristics of an anthocyanin-producing cell line from sweet potato storage root.

Anthocyanin pigments accumulated in a cell line derived from storage-root explants of sweet potato (Ipomoea batatas L.) cv 'Ayamurasaki'. Somatic pro-embryos were induced on the explants cultured on Murashige and Skoog medium supplemented with 1 mg/l 2,4-D. The pro-embryo structures produced callus when transferred to MS medium with 0.5 mg/l 2,4-D. A cell line was isolated from this callus which accumulated anthocyanin pigment. The color value of the pigment extracted after 27 days of culture in MS medium with 2 mg/l 2,4-D was 8.2, which was very close to that of a pigment extracted from roots, which was 8.9. Most of the pigments from the cell extract were hydrophilic and appeared on the ODS-column HPLC with a lower retention time than the main anthocyanins of the root tissues. The majority of the pigments were identical with the root anthocyanins. Cell line-specific anthocyanins were detected.

Six Diacylated Anthocyanins from the Storage Roots of Purple Sweet Potato, Ipomoea batatas.

Eight acylated anthocyanins were isolated from the storage roots of the purple sweet potato, Ipomoea batatas cv Yamagawamurasaki, which is the source of the food colorant "purple sweet potato color." Of these, six pigments were identified as diacylated anthocyanins, cyanidin and peonidin 3-O-(6-O-(E)-caffeyl-2-O-(6-O-acyl- ß-D-glucopyranosyl)-ß-D-glucopyranoside)-5-O-ß-D-gluco-pyranosides, in which each acyl subsutituent was a p-hydroxybenzoyl, (E)-caffeyl or (E)-ferulyl residue, mainly by NMR analyses.

Eight new anthocyanins, ternatins C1-C5 and D3 and preternatins A3 and C4 from young clitoria ternatea flowers

Eight new anthocyanins 1-8 (ternatins C1, C2, C3, C4, C5, and D3 and preternatins A3 and C4) were isolated from Clitoria ternatea flowers. By the application of chemical, UV-vis, and FABMS methods, the structures of 1-6 were postulated as delphinidin 3-malonylglucoside having 3'-GCGC-5'-G, 3'-GCGCG-5'-G, 3'-GC-5'-G, 3'-GCG-5'-G, 3'-G-5'-G, and 3'-GC-5'-GC, and compounds 7 and 8 as delphinidin 3-glucoside having 3'-GCG-5'-GCG and 3'-GCG-5'-G as side chains, respectively, in which Dp is delphinidin, G is D-glucose, and C is p-coumaric acid. The structures of the compounds 1, 3-5, and 7 were established completely by additional NMR methods.

Two acylated anthocyanins from purple sweet potato.

Two new acylated anthocyanins were isolated from the storage root of Ipomoea batatas. On the basis of spectroscopic analyses, these compounds were identified as the 3-O-(6-O-trans-caffeyl-2-O-beta-glucopyranosyl-beta-glucopyranoside)-5-O - beta-glucoside of cyanidin and peonidin.

New Acylated Anthocyanins from Brassica campestris var. chinensis.

Two new acylated anthocyanins were isolated from beninabana, Brassica campestris var. chinensis, in addition to two known anthocyanins. The structures were established by spectral analyses.

Triacylated anthocyanins from Ajuga reptans flowers and cell cultures.

Four anthocyanins were isolated from Ajuga reptans flowers and one from the cell cultures. By FAB mass spectrometry measurements, the structures of these pigments were determined as delphinidin and cyanidin glucosides acylated with two cinnamic acids, while three of them were also malonylated. A delphinidin-based pigment in the crude extract from cell cultures was identical to the major flower pigment as shown by HPLC co-chromatography. Moreover, by application of 1H and 13C NMR consisting of DQF-COSY, NOESY, ROESY, 2D-HOHAHA, HSQC and HMBC methods, the structures of two new anthocyanins were identified as delphinidin and cyanidin 3-O-(2-O-(6-O-(E)-p-coumaryl-beta-D-glucopyranosyl)-(6-O-(E)-p- coumaryl)-beta-D-glucopyranosyl)-5-O-(6-O-malonyl-beta-D-glucopyranoside ). The deacylated anthocyanins were confirmed as delphinidin and cyanidin 3-sophoroside-5-glucosides.

Five new anthocyanins, ternatins A3, B4, B3, B2, and D2, from Clitoria ternatea flowers.

Five new ternatins 1-5 have been isolated from Clitoria ternatea flowers, and the structures have been determined by chemical and spectroscopic methods as delphinidin 3-malonylG having 3'-GCG-5'-GCG, 3'-GCG-5'-GC, 3'-GCGCG-5'-GC, 3'-GCGC-5'-GCG, and 3'-GCGC-5'-GC side chains, respectively, in which G is D-glucose and C is p-coumaric acid. Pigment 1 had symmetric 3',5'-side chains. Compounds 3 and 4 are structural isomers. These ternatins were shown to form an intramolecular stacking between the aglycon ring and the 3',5'-side chains in solution.

Malonylated anthocyanins from bulbs of red onion, Allium cepa L.

Four cyanidin-based anthocyanins (1-4) were isolated from the red onion, Allium cepa L. Pigments 1 and 3 were identified as cyanidin 3-glucoside (Cy 3-Glc) and 3-malonylglucoside (Cy 3-MaGlc), respectively, by cochromatography with standard pigments. Anthocyanins 2 and 4 were respectively determined as cyanidin 3-laminaribioside (Cy 3-Lam) and 3-malonyllaminaribioside (Cy 3-MaLam), a new anthocyanin, mainly by NMR techniques. Malonylated anthocyanins 3 and 4 were found for the first time in red onions.