Takahiko Mitani

Caffeic Acid Inhibits Vascular Smooth Muscle Cell Proliferation Induced by Angiotensin II in Stroke-Prone Spontaneously Hypertensive Rats

Epidemiological studies have linked the consumption of phenolic acids with reduced risk of cardiovascular diseases. In the present study, we sought to investigate whether caffeic acid, a phenolic acid which is abundant in normal diet, can antagonize angiotensin II (Ang II)-induced vascular smooth muscle cell (VSMC) proliferation in stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto (WKY) rats, and if so, to elucidate the underlying cell signaling mechanisms. We exposed VSMCs to Ang II and caffeic acid and found that caffeic acid significantly inhibited intracellular superoxide anion generation (decreased from 127±6.3% to 100.3±6.6% of the control cells) and the cell proliferation induced by Ang II. Furthermore, caffeic acid significantly abolished the tyrosine phosphorylation of JAK2 (decreased from 7.4 ±0.6-fold to 2.4±0.6-fold at 2 min) and STAT1 (decreased from 1.8±0.2-fold to 0.5±0.1-fold at 2 min) and the phosphorylation of ERK1/2 (decreased from 99.2±10.2-fold to 49.8 ±10.9-fold at 2 min) that were induced by Ang II. These effects of caffeic acid were consistent with the inhibition of the proliferation of VSMCs by DPI, an NADPH oxidase inhibitor, and by AG-490, a JAK2 inhibitor. In conclusion, our findings suggest that caffeic acid attenuates the proliferative reaction of VSMCs to Ang II stimulation in both SHRSP and WKY rats by inhibiting the generation of reactive oxygen species and then partially blocking the JAK/STAT signaling cascade and the Ras/Raf-1/ERK1/2 cascade.

A new bipyrrole and some phenolic constituents in prunes (Prunus domestica L.) and their oxygen radical absorbance capacity (ORAC).

Isolation and structural elucidation of prune constituents were performed and total 10 compounds were determined by NMR and MS analyses. A novel compound was identified to be 2-(5-hydroxymethyl-2′,5′-dioxo-2′,3′,4′,5′-tetrahydro-1′H-1,3′-bipyrrole)carbaldehyde, and 7 phenolic compounds were isolated from prunes for the first time. In addition, antioxidant activity of them was evaluated on the basis of the oxygen radical absorbance capacity (ORAC).

Phenolics Profile of Mume, Japanese Apricot(Prunus mume Sieb. et Zucc.)fruit

The fruit of mume, Japanese apricot (Prunus mume Sieb. et Zucc.), was evaluated for its phenolics content, high performance liquid chromatography (HPLC) profile and antioxidative activities. The phenolics content of mume fruit was relatively high, the flesh of fully matured fruit containing up to 1% of phenolics on a dry weight basis. Reflecting such a high content of phenolics, the ORAC (oxygen radical absorbance capacity) value for mume fruit flesh showed high values, ranging from 150 to 320 µmol/g Trolox equivalent, depending upon the stage of maturation. 5-O-Caffeoylqunic acid (chlorogenic acid), 3-O-caffeoylquinic acid and tetra-O-acylated sucrose-related compounds were isolated from the flesh of mume fruit, although many unknown peaks were also apparent in the HPLC chromatogram. An alkali hydrolysate comprised four main phenolic acids, caffeic acid, cis/trans-p-coumaric acid and ferulic acid. No flavonoids were observed in the analysis. These results suggest that the majority of phenolics in mume fruit were hydroxycinnamic acid derivatives.

Synthetic Studies on Selectin Ligands/Inhibitors: One-Pot Synthesis of the Mono- and Oligo-Sulfated 2-(Tetradecyl)Hexadecyl β-D-Galacto- and Lactopyranosides as the Sulfatide Mimetics 1

Abstract Regioselective sulfation through the dibutylstannylene acetals was applied to the key step to prepare a number of sulfated saccharides which are active as the inhibitors of L- and P-selectin. The number and the positions of the sulfate groups were confirmed by NMR and MS analyses. Using this methodology, our target sulfated glycolipids (6-9, 12-14) were conveniently synthesized in one-pot from free 2-(tetradecyl)hexadecyl β-D-galactopyranoside 5 and lactoside 11. 1. Synthetic studies on sialoglycoconjugates, Part 97. For Part 96, see E. Tanahashi, K. Murase, M. Shibuya, Y. Igarashi, H. Ishida, A. Hasegawa and M. Kiso, J. Carbohydr. Chem., previous paper this issue.