Anti-oxidative, anti-tumor-promoting, and anti-carcinogensis activities of nitroastaxanthin and nitrolutein, the reaction products of astaxanthin and lutein with peroxynitrite.

Astaxanthin captured peroxynitrite to form nitroastaxanthins. 15-Nitroastaxanthin was a major reaction product of astaxanthin with peroxynitrite. Here, the anti-oxidative, anti-tumor-promoting, and anti-carcinogensis activities of 15-nitroastaxanthin were investigated. In addition to astaxanthin, 15-nitroastaxanthin showed excellent singlet oxygen quenching activity. Furthermore, 15-nitroastaxanthin showed inhibitory effects of in vitro Epstein-Barr virus early antigen activation and two-stage carcinogensis on mouse skin papillomas. These activities were slightly higher than those of astaxanthin. Similar results were obtained for the 15-nitrolutein, a major reaction product of lutein with peroxynitrite.

Auto-oxidation products of astaxanthin.

The auto-oxidation products of astaxanthin were investigated. Astaxanthin was allowed to react with atmospheric oxygen at 55°C in the dark for 35 days. A series of oxidative cleavage products, 7-apoastaxanthinal (1), 9-apoastaxanthinone (2), 11-apoastaxanthinal (3), 13-apoastaxanthinone (4), 15-apoastaxanthinal (5), 14'-apoastaxanthinal (6), 12'-apoastaxanthinal (7), 10'-apoastaxanthinal (8), and 8'-apoastaxanthinal (9), were identified. Among them, 3 and 6 were isolated and characterized for the first time. Cleavage of the double bond in astaxanthin was discussed on the basis of the calculation of the stable molecular energy.

Nitrocapsanthin and nitrofucoxanthin, respective products of capsanthin and fucoxanthin reaction with peroxynitrite.

The in vitro reactivity of capsanthin (1) and fucoxanthin (2) with peroxynitrite was investigated, and the reaction products produced by scavenging with peroxynitrite were analyzed. (14'Z)-Nitrocapsanthin (3) and 12-nitrocapsanthin (4) were isolated from the products of the reaction of capsanthin with peroxynitrite. Similarly, (14Z)-15-nitrofucoxanthin (5), (11Z)-11-nitrofucoxanthin (6), and (14Z,9'Z)-15-nitrofucoxanthin (7) were obtained from the reaction of peroxynitrite reaction with fucoxanthin. Capsanthin and fucoxanthin inhibited the nitration of tyrosine by peroxynitrite. Furthermore, nitrocapsanthins (3 and 4) and nitrofucoxanthins (5 and 6) exhibited an inhibitory effect on Epstein-Barr virus early antigen activation in Raji cells and an antiproliferative effect on human pancreatic carcinoma. Moreover, nitrocapsanthins (3 and 4) inhibited carcinogensis of mouse skin tumors initiated by 7,12-dimethylbenz[a]anthracene (DMBN).

Functional compounds in fermented buckwheat sprouts.

Fermented buckwheat sprouts (FBS) are used as multifunctional foods. Their production process includes fermentation with lactic acid bacteria. The major strains were found to include Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus pentosus, Lactococcus lactis subsp. lactis, and Pediococcus pentosaceus in an investigation of the lactic acid bacteria. We searched for the functional components, and nicotianamine (NA) and 2″-hydroxynicotianamine (HNA) were identified as angiotensin I-converting enzyme (ACE) inhibitors. NA and HNA increased during fermentation. Indole-3-ethanol was identified as an antioxidant (a SOD active substance), and may have been generated from tryptophan during fermentation because it was not contained in green buckwheat juice. A safety test demonstrated that FBS contained were safe functional food components, showing negative results in buckwheat allergy tests. Any buckwheat allergy substances might have been degraded during the fermentation process.

Sub-critical water extraction of residual green tea to produce a roasted green tea-like extract.

In this study, we investigated the effects of various temperatures between 140 to 260 degrees C during sub-critical water extraction of residual green tea in making a roasted green tea-like extract, a popular beverage in Japan. Each residual green tea extract was analyzed for sensory properties and antioxidative activities, and this revealed 140 degrees C to be the best extraction temperature. 5-Hydroxymethyl-2-furaldehyde, (+)-catechin, and (-)-epicatechin were found to be the major antioxidative compounds in the 140 degrees C extract, along with theanine and some important amino acids.

A new biisoflavonoid from the roots of Erythrina variegata.

A new biisoflavonoid, biseryvarin A (1a), together with two known compounds were isolated from the roots of Erythrina variegata. The structure of biseryvarin A was established on the basis of spectroscopic evidence. Biseryvarin A is the first dimeric isoflavonoid possessing isoprenoid groups from the genus Erythrina. Biseryvarin A showed low activity against methicillin-resistant Staphylococcus aureus (MRSA).

Reaction of astaxanthin with peroxynitrite.

The in vitro reactivities of astaxanthin toward peroxynitrite were investigated and the reaction products after scavenging with peroxynitrite were analyzed in order to determine the complete mechanism of this reaction. A series of carotenoids, 13-apo-astaxanthinone (1), 12'-apo-15'-nitroastaxanthinal (2), 12'-apo-astaxanthinal (3), 10'-apo-astaxanthinal (4), 9-cis-14'-s-cis-15'-nitroastaxanthin (5), 14'-s-cis-15'-nitroastaxanthin (6), 13-cis-14'-s-cis-15'-nitroastaxanthin (7), 10'-s-cis-11'-cis-11'-nitroastaxanthin (8), 13,15,13'-tri-cis-15'-nitroastaxanthin (9), 9-cis-astaxanthin (10), and 13-cis-astaxanthin (11), were isolated from the reaction products of carotenoids with peroxynitrite. Our previous studies achieved for the first time the isolation of nitro derivatives from the reaction of astaxanthin with peroxynitrite. Here we identify the major remaining reaction products of this reaction and investigate the stabilities of the nitro astaxanthins.

A new Erythrina alkaloid from Erythrina herbacea.

A new Erythrina alkaloid, 10-hydroxy-11-oxoerysotrine (1), has been isolated from the flowers of Erythrina herbacea together with five known compounds: erytharbine (2), 10,11-dioxoerysotrine (3), erythrartine (4), erysotramidine (5) and erysotrine-N-oxide (6). The structure of the new compound was elucidated on the basis of its spectral data, including 2-D NMR and mass (MS) spectra. The new compound is a rare C-10 oxygenated Erythrina alkaloid. The antioxidant activities of the isolated compounds 1-6 were evaluated by scavenging with peroxynitrite.

Subcritical water extraction of barley to produce a functional drink.

We investigated the effects of various temperatures between 150 and 280 degrees C during subcritical water extraction of barley to make a barley tea-like extract, a popular summer beverage in Japan. Each barley extract was analyzed for sensory properties, antioxidative activity, and the amount of residual matter, which revealed 205 degrees C to be the best extraction parameter. 5-Hydroxymethyl-2-furaldehyde was found to be the major antioxidative component in the 205 degrees C extract, along with the formation of several important amino acids.

Reaction of retinol with peroxynitrite.

The reactivity of retinol with peroxynitrite, which is a strong oxidant and has been reported to induce several biological damages, was investigated. 13-cis-14-nitroretinol (1), 13-trans-14-nitroretinol (2), 13-apo-beta-carotenone (3), retinal (4), 11,14-epoxyretinol (5), and 11,15-epoxyretinol (6) were identified as reaction products of retinol with peroxynitrite. From these results, it was observed that retinol can undergo a nitration reaction with peroxynitrite. Furthermore, the formation mechanisms of 1, 2, and 3 from retinol with peroxynitrite are discussed.

Effect of the minor ABA metabolite 7'-hydroxy-ABA on Arabidopsis ABA 8'-hydroxylase CYP707A3.

To examine the effect of the minor abscisic acid (ABA) metabolite 7'-hydroxy-ABA on Arabidopsis ABA 8'-hydroxylase (CYP707A3), we developed a novel and facile, four-step synthesis of 7'-hydroxy-ABA from alpha-ionone. Structural analogues of 7'-hydroxy-ABA, 1'-deoxy-7'-hydroxy-ABA, and 7'-oxo-ABA were also synthesized to evaluate the role of the 7'-hydroxyl group on binding to the enzyme. The result of enzyme inhibition assay suggests that the local polarity at C-7', neither steric bulkiness nor overall molecular hydrophilicity, would be the major reason why (+)-7'-hydroxy-ABA is not a potent inhibitor of CYP707A3.

Anti-oxidative compounds in barley tea.

Five phenolic compounds, p-hydroxyacetophenone, 5,7-dihydroxychromone, naringenin, quercetin, and iso-americanol A, were found first time in the barley tea, together with the known compounds, p-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, p-hydroxybenzoic acid, vanillic acid, and p-coumaric acid. The anti-oxidative properties were evaluated by measuring their peroxynitrite-scavenging activities. Among these compounds, 3,4-dihydroxybenzaldehyde, p-coumaric acid, quercetin, and isoamericanol A showed stronger activities than that of BHT (butylated hydroxytoluene) at 400 microM.

Synergistic effects of mupirocin and an isoflavanone isolated from Erythrina variegata on growth and recovery of methicillin-resistant Staphylococcus aureus.

The phytochemical 2',4'-dihydroxy-8-gamma,gamma-dimethylallyl-2",2"-dimethylpyrano[5",6":6,7]isoflavanone (bidwillon B) was isolated from Erythrina variegata and its antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA) were investigated. Bidwillon B inhibited the growth of 12 MRSA strains at minimum inhibitory concentrations (MICs) of 3.13-6.25mg/l, while MICs of mupirocin were 0.20-3.13 mg/l. The minimum bactericidal concentration (MBC) for bidwillon B and mupirocin against MRSA were 6.25-25mg/l (MBC(90): 12.5mg/l) and 3.13-25mg/l (MBC(90): 25mg/l), respectively. When bidwillon B and mupirocin were combined, synergistic effects were observed for 11 strains of MRSA (fractional inhibitory concentration indices, 0.5-0.75). The MBCs of mupirocin in the presence of bidwillon B (3.13 mg/l) were reduced to 0.05-1.56 mg/l. Bidwillon B at MIC values strongly inhibited incorporation of radio-labelled thymidine, uridine, glucose and isoleucine into MRSA cells. Mupirocin showed lower inhibitory effects than bidwillon B on thymidine, uridine and glucose incorporation, but incorporation of isoleucine was completely blocked with this antibiotic. These results indicate that bidwillon B possesses sufficient anti-MRSA activity for inhibiting growth and recovery, and that the compound acts synergistically with mupirocin. The results also suggest that both compounds act on MRSA via different mechanisms. Bidwillon B may prove to be a potent phytotherapeutic and/or combination agent with mupirocin in the elimination of nasal and skin carriage of MRSA.

Six new constituents from the roots of Erythrina variegata.

Three new isoflavonoids, eryvarins M-O (1-3), two new 2-arylbenzofurans, eryvarins P and Q (4 and 5), and a new 3-aryl-2,3-dihydrobenzofuran, eryvarin R (6), together with three known compounds, were isolated from the roots of Erythrina variegata. The structures of these compounds were established by spectroscopic analysis. Eryvarin R (6) is an unusual 3-aryl-2,3-dihydrobenzofuran derivative with a formyl (CHO) group. Eryvarin Q (5) showed potent antibacterial activity against methicillin-resistant Staphylococcus aureus.

Isoflavonoids from roots of Erythrina zeyheri.

Five isoflavonoids, (+/-)-7,2',4'-trihydroxy-8,3'-di(gamma,gamma-dimethylallyl)isoflavanone, (3R)-7,4'-dihydroxy-2'-methoxy-6,8-di(gamma,gamma-dimethylallyl)isoflavanone, (3R)-7,2',4'-trihydroxy-6,8-di(gamma,gamma-dimethylallyl)isoflavan, 2',4'-dihydroxy-8-gamma,gamma-dimethylallyl-2",2"-dimethylpyrano-[5,6:6,7]isoflavan and (6aS, 11aS)-3,6a-dihydroxy-9-methoxy-4,10-di(gamma,gamma-dimethylallyl)pterocarpan, along with five known compounds, were isolated from the roots of Erythrina zeyheri. Their structures were established on the basis of spectroscopic evidence, and their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) were estimated by determining minimum inhibitory concentrations.

9-Oxo-neoprocurcumenol from Curcuma aromatica (Zingiberaceae) as an attachment inhibitor against the blue mussel, Mytilus edulis galloprovincialis.

Neocurdione, isoprocurcumenol, and a new sesquiterpene, 9-oxo-neoprocurcumenol, were isolated from fresh rhizomes of Curcuma aromatica and Curcuma zedoaria (Zingiberaceae) as attachment inhibitors against the blue mussel, Mytilus edulis galloprovincialis. The structures of these compounds were elucidated on the basis of spectroscopic evidence.

An arylbenzofuran and four isoflavonoids from the roots of Erythrina poeppigiana.

An arylbenzofuran, erypoegin F and four isoflavonoids, erypoegins G-J, together with six known compounds were isolated from the roots of Erythrina poeppigiana, and their structures were elucidated on the basis of spectroscopic evidence. Erypoegin F is a rare 2-arylbenzofuran possessing a formyl group from a natural source, and erypoegin I is the first naturally occurring isoflavonoid with a 2-oxo-3-methylbutyl group.

Eryvarins F and G, two 3-phenoxychromones from the roots of Erythrina variegata.

Two 3-phenoxychromones, eryvarins F and G, were isolated from the roots of Erythrina variegata. Their structures were established to be 3-(2,4-dihydroxyphenoxy)-7-hydroxy-6,8-di(3,3-dimethylallyl)chromen-4-one and 3-(2,4-dihydroxyphenoxy)-8-(3,3-dimethylallyl)-2,2-dimethylpyrano[5,6:6,7]chromen-4-one on the basis of spectroscopic and chemical evidence. Eryvarins F and G are unusual 3-phenoxychromone derivatives with two isoprenoid groups.

Oxygenated lycopene and dehydrated lutein in tomato puree.

Oxygenated lycopenes, (2S*,5S*,6R*)-2,6-cyclolycopene-1-methoxy-5-ol, (2S*,5S*,6R*)-1,16-didehydro-2,6-cyclolycopene-5-ol and (3R,6'R)-3-hydroxy-3',4'-didehydro-beta,gamma-carotene (anhydrolutein I) were isolated from tomato puree. The structures of these compounds were elucidated on the basis of spectroscopic evidence.

Two diphenylpropan-1,2-diol syringates from the roots of Erythrina variegata.

Two new diphenylpropan-1,2-diols, eryvarinols A (1) and B (2), were isolated from the roots of Erythrina variegata. Their structures were elucidated as 1-(4-hydroxy-2-methoxyphenyl)-2-(4-hydroxy-3,5-dimethoxybenzoyloxy)-3-(4-hydroxyphenyl)propan-1-ol (1) and its 3"-prenyl derivative (2) on the basis of spectroscopic and chemical evidence. Both these compounds are unusual diphenylpropan-1,2-diols with a syringyl group.