(±)-Carquinostatin Aの全合成と(R)-(−)-及び (S)-(+)-Carquinostatin Aの不斉全合成研究(発表論文抄録(2012))

Total syntheses of (±)-carquinostatin A (1), and (R)-(−)-carquinostatin A (1a) together with its enantiomer, (S)-(+)-carquinostatin A (1b), possessing radical scavenging activity, were newly achieved. (±)-Carquinostatin A (1) was synthesized from 1-acetonyl-6-bromo-3-ethoxy-2-methylcarbazole (6), which was derived from the known 1-acetonyl-3-ethoxy-2-methylcarbazole (5). Introduction of a prenyl group at the 6-position of carbazole was successful in two steps. For the synthesis of (R)-(−)-carquinostatin A (1a) and (S)-(+)-carquinostatin A (1b), (R)-(−)-1-(2-acetoxypropyl)-3-hydroxy-2-methylcarbazole (15a) and (S)-(+)-3-hydroxy-1-(2-hydroxypropyl)-2-methylcarbazole (15b), prepared by lipase-QLM catalyzed enantioselective transesterification of 3-hydroxy-1-(2-hydroxypropyl)-2-methylcarbazole (14), were used as the chiral starting material.Total syntheses of (±)-carquinostatin A (1), and (R)-(−)-carquinostatin A (1a) together with its enantiomer, (S)-(+)-carquinostatin A (1b), possessing radical scavenging activity, were newly achieved. (±)-Carquinostatin A (1) was synthesized from 1-acetonyl-6-bromo-3-ethoxy-2-methylcarbazole (6), which was derived from the known 1-acetonyl-3-ethoxy-2-methylcarbazole (5). Introduction of a prenyl group at the 6-position of carbazole was successful in two steps. For the synthesis of (R)-(−)-carquinostatin A (1a) and (S)-(+)-carquinostatin A (1b), (R)-(−)-1-(2-acetoxypropyl)-3-hydroxy-2-methylcarbazole (15a) and (S)-(+)-3-hydroxy-1-(2-hydroxypropyl)-2-methylcarbazole (15b), prepared by lipase-QLM catalyzed enantioselective transesterification of 3-hydroxy-1-(2-hydroxypropyl)-2-methylcarbazole (14), were used as the chiral starting material

Influence of gallate and pyrogallol moieties on the intestinal absorption of (-)-epicatechin and (-)-epicatechin gallate.

The cellular accumulation of individual catechins was measured as an index of intestinal absorption to clarify the interactions among catechins. The cellular accumulation of (-)-epicatechin (EC) increased in the presence of other catechins. The ability of gallate catechin such as (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) to increase the cellular accumulation of EC was greater than that of nongallate catechins. Gallic acid octyl ester (GAO) also increased the cellular accumulation of EC by 426% as compared with that in untreated cells. Conversely, the cellular accumulation of ECG was not influenced by other catechins, but it increased by 54% in the presence of GAO. Experiments using GAO derivatives indicated that the gallate moiety required the presence of a catechol group and a neighboring carbonyl group, whereas the pyrogallol moiety, without a neighboring carbonyl group, required 3 hydroxyl groups to increase the cellular accumulation of EC. Furthermore, gallate esters required long carbon chains to increase the same. The experiment using EGCG, GAO, or their derivatives indicated that the ability of gallate or pyrogallol moiety to increase the cellular accumulation of EC was restricted by their hydrophobicity. These results suggest that the co-administration of foods containing functional materials such as gallate or pyrogallol moieties, increases the intestinal absorption of catechin.The cellular accumulation of (-)-epicatechin increased by the gallate or pyrogallol moiety in catechin structure. The interaction among catechins appeared to affect intestinal absorption of catechin. The bioavailability of catechin may be improved by co-administration of functional foods.The cellular accumulation of individual catechins was measured as an index of intestinal absorption to clarify the interactions among catechins. The cellular accumulation of (-)-epicatechin (EC) increased in the presence of other catechins. The ability of gallate catechin such as (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) to increase the cellular accumulation of EC was greater than that of nongallate catechins. Gallic acid octyl ester (GAO) also increased the cellular accumulation of EC by 426% as compared with that in untreated cells. Conversely, the cellular accumulation of ECG was not influenced by other catechins, but it increased by 54% in the presence of GAO. Experiments using GAO derivatives indicated that the gallate moiety required the presence of a catechol group and a neighboring carbonyl group, whereas the pyrogallol moiety, without a neighboring carbonyl group, required 3 hydroxyl groups to increase the cellular accumulation of EC. Furthermore, gallate esters required long carbon chains to increase the same. The experiment using EGCG, GAO, or their derivatives indicated that the ability of gallate or pyrogallol moiety to increase the cellular accumulation of EC was restricted by their hydrophobicity. These results suggest that the co-administration of foods containing functional materials such as gallate or pyrogallol moieties, increases the intestinal absorption of catechin.The cellular accumulation of (-)-epicatechin increased by the gallate or pyrogallol moiety in catechin structure. The interaction among catechins appeared to affect intestinal absorption of catechin. The bioavailability of catechin may be improved by co-administration of functional foods

Efficacy of dibenzoylmethane derivatives in protecting against endoplasmic reticulum stress and inhibiting nuclear factor kappa B on dextran sulfate sodium induced colitis in mice.

We recently reported that some dibenzoylmethane (DBM) derivatives have a protective effect against endoplasmic reticulum (ER) stress and inhibit nuclear factor kappa B (NF-κB). The aim of this study was to evaluate the effect of DBM derivatives against dextran sulfate sodium (DSS)-induced colitis in mice. The DBM derivatives used in this study were 4,4\u27-dibromodibenzoylmethane that protects against ER stress, and, 4,4\u27-dichlorodibenzoylmethane that protects against ER stress and inhibits NF-κB. In each group, the presence of faecal occult blood, the disease activity index score (DAI score) and intestinal length were examined. Both of the DBM derivatives with protective effects against ER stress significantly improved occult bleeding of the colitis induced by DSS. The 4,4\u27-dichlorodibenzoylmethane significantly reduced the DAI score and inhibited the shortening of colon length, but the 4,4\u27-dibromodibenzoylmethane did not. These findings suggest that both the protective effect against ER stress and inhibitory effect on NF-κB are needed in the treatment of DSS-induced colitis. Therefore, the effect of 4,4\u27-dichlorodibenzoylmethane maybe beneficial in the therapeutic regulation of ulcerative colitis.We recently reported that some dibenzoylmethane (DBM) derivatives have a protective effect against endoplasmic reticulum (ER) stress and inhibit nuclear factor kappa B (NF-κB). The aim of this study was to evaluate the effect of DBM derivatives against dextran sulfate sodium (DSS)-induced colitis in mice. The DBM derivatives used in this study were 4,4\u27-dibromodibenzoylmethane that protects against ER stress, and, 4,4\u27-dichlorodibenzoylmethane that protects against ER stress and inhibits NF-κB. In each group, the presence of faecal occult blood, the disease activity index score (DAI score) and intestinal length were examined. Both of the DBM derivatives with protective effects against ER stress significantly improved occult bleeding of the colitis induced by DSS. The 4,4\u27-dichlorodibenzoylmethane significantly reduced the DAI score and inhibited the shortening of colon length, but the 4,4\u27-dibromodibenzoylmethane did not. These findings suggest that both the protective effect against ER stress and inhibitory effect on NF-κB are needed in the treatment of DSS-induced colitis. Therefore, the effect of 4,4\u27-dichlorodibenzoylmethane maybe beneficial in the therapeutic regulation of ulcerative colitis

Synthesis and antimalarial activity of calothrixins A and B, and their N-alkyl derivatives.

We synthesized calothrixin B using our developed biomimetic method and derived N-alkyl-calothrixins A and B. The in vitro antimalarial activity of the calothrixin derivatives, including calothrixins A and B, against the Plasmodium falciparum FCR-3 strain was evaluated. All test compounds exhibited antimalarial activity over a concentration range of 6.4×10(-6)-1.2×10(-7) M.We synthesized calothrixin B using our developed biomimetic method and derived N-alkyl-calothrixins A and B. The in vitro antimalarial activity of the calothrixin derivatives, including calothrixins A and B, against the Plasmodium falciparum FCR-3 strain was evaluated. All test compounds exhibited antimalarial activity over a concentration range of 6.4×10(-6)-1.2×10(-7) M