Norihiko Terahara

Molecular Mechanisms Behind the Chemopreventive Effects of Anthocyanidins

Anthocyanins are polyphenolic ring-based flavonoids, and are widespread in fruits and vegetables of red-blue color. Epidemiological investigations and animal experiments have indicated that anthocyanins may contribute to cancer chemoprevention. The studies on the mechanism have been done recently at molecular level. This review summarizes current molecular bases for anthocyanidins on several key steps involved in cancer chemoprevention: (i) inhibition of anthocyanidins in cell transformation through targeting mitogen-activated protein kinase (MAPK) pathway and activator protein 1 (AP-1) factor; (ii) suppression of anthocyanidins in inflammation and carcinogenesis through targeting nuclear factor kappa B (NF-κB) pathway and cyclooxygenase 2 (COX-2) gene; (iii) apoptotic induction of cancer cells by anthocyanidins through reactive oxygen species (ROS) / c-Jun NH2-terminal kinase (JNK)-mediated caspase activation. These data provide a first molecular view of anthocyanidins contributing to cancer chemoprevention.

Identification of an anthocyanin occurring in some red wines

Abstract An anthocyanin-type pigment, vitisin A, was found in small amounts in some red wines and at trace levels in stored grapes. HPLC and spectrophotometric analysis showed that vitisin A exhibited a unique UV-Vis spectrum. Vitisin A was isolated, purified and identified using FAB mass spectrometry and NMR. The aglycone, vitisidin A, is 68 mass units greater than malvidin, accounted for by an additional C 3 O 2 substituent. Further accurate mass determinations and NMR studies of both malvidin 3-glucoside and vitisin A confirmed that vitisin A is based on malvidin 3-glucoside with an additional C 3 O 2 between position 4 and the 5-hydroxyl of the molecule. Five different isomers were distinguished by NMR, namely the flavylium cation, quinonoidal base, chalcone form and two carbinol pseudobases. The assignment of one of the protons remains tentative due to the rapid hydrogen/deuterium exchange. The structure was determined to be 3-formyl-4- d -β-glucopyranosyloxy-8-hydroxy-5-(4-hydroxy-3,5-dimethoxy)phenyl-2-oxo-1,6-dioxa-2,3-dihydrophenalene.

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-β-D-glucopyranosyl)-β-D-glucopyranoside) -5-O-β-D-glucopyranoside, cyanidin 3-O-(2-O-(6-O-(E)-p -coumaroyl-β-D-glucopyranosyl)-6-O-(E)-caffeoyl-β-D-glucopyranoside)-5-O-β-D-glucopyranoside, cyanidin 3-O-(2-O-(6-O-(E)-p -coumaroyl-β-D-glucopyranosyl)-6-O-(E)-p-coumaroyl-β-D-glucopyranoside)- 5-O-β-D-glucopyranoside, and peonidin 3-O-(2-O-(6-O-(E)-p -coumaroyl-β-D-glucopyranosyl)-6-O-(E)-p-coumaroyl-β-D-glucopyranoside)-5-O-β-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.

Caffeoylsophorose, a New Natural α-Glucosidase Inhibitor, from Red Vinegar by Fermented Purple-Fleshed Sweet Potato

The suppressive effect on the postprandial blood glucose rise through α-glucosidase (AGH) inhibition was investigated in this study in order to clarify an antihyperglycemic function of 6-O-caffeoylsophorose (CS) from diacylated anthocyanin. The administration of CS (100 mg/kg) following maltose (2 g/kg) to Sprague-Dawley rats resulted in the maximal blood glucose level after 30 min being significantly decreased by 11.1% compared to the control. A reduction in the serum insulin secretion was also observed in parallel to the decrease in blood glucose level. No blood glucose change was apparent when sucrose or glucose was ingested, suggesting that the antihyperglycemic effect of CS was achieved by maltase inhibition, rather than by sucrase or glucose transport inhibition. An AGH inhibitory assay demonstrated that the non-competitive maltase inhibition of CS was partly due to acylation by phenolic acid with sugar, the presence of hydroxyl groups in the aromatic ring, and the presence of an unsaturated alkyl chain in the acylated moiety.

Anthocyanin Compositions in Sweetpotato (Ipomoea batatas L.) Leaves

The anthocyanin composition of three varieties, Simon No. 1, Kyushu No. 119, and Elegant Summer, in sweetpotato (Ipomoea batatas L.) leaves was examined for promoting new uses. Fifteen anthocyanin compounds were identified and measured. HPLC clearly showed quantitative differences, but not qualitative ones. The anthocyanins were acylated cyanidin and peonidin type. The result suggests that the major anthocyanin composition of sweetpotato leaves is cyanidin type.

Acylated anthocyanins of Clitoria ternatea flowers and their acyl moieties.

Abstract Two acyl moieties, prepared by alkaline deacylation or H2O2 oxidation of ternatin mixture from Clitoria ternatea flowers, were determined as E-4-O-β- d -glucopyranosyl-p-coumaric acid and 6-O-malonyl- d -glucopyranose respectively through FABMS and NMR. Furthermore, six ternatins A1, A2, B1, B2, D1 and D2 in C. ternatea flowers were isolated by reversed phase HPLC and their structures were partly characterized as highly acylated delphinidin derivatives.

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.

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.

Anthocyanins acylated with malic acid in Dianthus caryophyllus and D. deltoides

Abstract The major anthocyanin in pink and red forms of Dianthus caryophyllus has been identified as pelargonidin 3-malylglucoside. The corresponding cyanidin 3-malylglucoside has been found in red flowers of D. deltoides. This is the first complete characterization in plants of anthocyanins substituted with malic acid.

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.