Takao Ikami

Amla (Emblica officinalis Gaertn.) extract promotes procollagen production and inhibits matrix metalloproteinase-1 in human skin fibroblasts

AIM OF THE STUDY Emblica officinalis Gaertn., commonly known as amla, is a rich dietary source of vitamin C, minerals and amino acids, and also contains various phenolic compounds. Amla extract is also known to exhibits potent antioxidant properties and to provide protection for human dermal fibroblasts against oxidative stress, and therefore it is thought to be useful for natural skin care. In this study, we investigated the effects of amla extract on human skin fibroblasts, especially for production of procollagen and matrix metalloproteinases (MMPs), in vitro. MATERIALS AND METHODS Mitochondrial activity of human skin fibroblasts were measured by WST-8 assay. Quantification of procollagen, MMPs, and Tissue inhibitor of metalloproteinase-1 (TIMP-1) released from human skin fibroblasts were performed by immunoassay technique. RESULTS AND CONCLUSIONS Amla extract stimulated proliferation of fibroblasts in a concentration-dependent manner, and also induced production of procollagen in a concentration- and time-dependent manner. Conversely, MMP-1 production from fibroblasts was dramatically decreased, but there was no evident effect on MMP-2. TIMP-1 was significantly increased by amla extract. From these results, it appears that amla extract works effectively in mitigative, therapeutic and cosmetic applications through control of collagen metabolism.

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).

Characterization and Antioxidative Properties of Oligomeric Proanthocyanidin from Prunes, Dried Fruit of Prunus domestica L.

A prune extract was separated by an antioxidant-guided assay to obtain an oligomeric proanthocyanidin fraction. The antioxidative oligomer was characterized as a procyanidin oligomer with an average polymerization degree of five and composed of epicatechin and catechin units. The antioxidative activity of the oligomer showed greater potency than chlorogenic acid which is known as an antioxidative component in prunes.

Synthesis and biological activity of glycolipids, with a focus on gangliosides and sulfatide analogs.

Publisher Summary Glycosphingolipids, composed of a complex carbohydrate chain and a hydrophobic ceramide, are localized primarily on outer cell surfaces and are particularly abundant in nervous tissues. Sialic acid and sulfate-containing glycoconjugates have been recognized to play important roles in many biological processes, such as cell adhesion, cell differentiation and proliferation, immune responses, receptor functions for viruses and bacterial toxins, and tumor progression. In particular, studies of the selectin family and sialoadhesin family (I-type lectins) have demonstrated the critical importance of protein-carbohydrate binding in cell-cell interactions, providing new opportunities for the development of therapeutic agents based on carbohydrates as binding inhibitors. Studies using chemically synthesized gangliosides have shown that gangliosides are potent inhibitors of cellular immune responses and that the structures of gangliosides influence their activity greatly. This chapter describes mainly the synthesis and biological evaluation of glycolipids, with a focus on gangliosides and sulfatide analogs.

Amla Enhances Mitochondrial Spare Respiratory Capacity by Increasing Mitochondrial Biogenesis and Antioxidant Systems in a Murine Skeletal Muscle Cell Line

Amla is one of the most important plants in Indian traditional medicine and has been shown to improve various age-related disorders while decreasing oxidative stress. Mitochondrial dysfunction is a proposed cause of aging through elevated oxidative stress. In this study, we investigated the effects of Amla on mitochondrial function in C2C12 myotubes, a murine skeletal muscle cell model with abundant mitochondria. Based on cell flux analysis, treatment with an extract of Amla fruit enhanced mitochondrial spare respiratory capacity, which enables cells to overcome various stresses. To further explore the mechanisms underlying these effects on mitochondrial function, we analyzed mitochondrial biogenesis and antioxidant systems, both proposed regulators of mitochondrial spare respiratory capacity. We found that Amla treatment stimulated both systems accompanied by AMPK and Nrf2 activation. Furthermore, we found that Amla treatment exhibited cytoprotective effects and lowered reactive oxygen species (ROS) levels in cells subjected to t-BHP-induced oxidative stress. These effects were accompanied by increased oxygen consumption, suggesting that Amla protected cells against oxidative stress by using enhanced spare respiratory capacity to produce more energy. Thus we identified protective effects of Amla, involving activation of mitochondrial function, which potentially explain its various effects on age-related disorders.

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.

EFFECTS OF PRUNE EXTRACT ON BLOOD PRESSURE ELEVATION IN STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

1 Prunes are recognized as a health food. They contain large amounts of phenolics and show high anti‐oxidant activity. In this study, both hydroxyl radicals and superoxide anion were scavenged by prune extract in electron spin resonance (ESR) analysis. 2 In angiotensin II challenged vascular smooth muscle cells (VSMCs) from stroke‐prone spontaneously hypertensive rats (SHRSP), the reactive oxygen species (ROS) level was decreased in caffeic acid‐treated cells compared with the control. 3 After 5 weeks of prune extract treatment, the elevation of blood pressure in the prune extract‐treated SHRSP was suppressed in comparison with the control group. 4 Our findings suggest that prune extract may contribute to the primary prevention of cardiovascular diseases.

Synthetic Studies on Selectin Ligands/Inhibitors: Synthesis and Inhibitory Activity of 2-O-Fucosyl Sulfatides Containing 2-Branched Fatty Alkyl Residues in Place of Ceramide

Abstract To investigate the biological selectin-ligand interactions, four sulfated 2-O-α-L-fucopyranosyl β-D-galactopyranosides containing 2-branched fatty-alkyl residues in place of ceramide have been systematically synthesized. The target glycolipids were assayed for their ability to block the adhesion of HL-60 cells to immobilized P-, L- and E-selectin. Among them, 2-O-α-L-fucopyranosyl sulfatide, which is anchored with 2-(tetradecyl) hexadecyl residue showed significantly more potency of the blocking adhesion to P- and L-selectins.

Synthetic Studies on Selectin Ligands/Inhibitors: Synthesis and Biological Activity of the Sulfated and Phosphorylated Multivalent β-D-Galactopyranosides Containing Fatty Alkyl Residues 1 2

Abstract Ten sulfated and three phosphorylated β-D-galactopyranoside dimers and one sulfated β-D-galactopyranoside trimer containing fatty alkyl residues in place of ceramide have been synthesized. The coupling of 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide (2) with branched fatty alkyl diols and a triol (1a-1j) using mercury bromide as an activating agent gave the corresponding parent glycolipids (4a-4j) in good yields. Regioselective sulfation of these parent glycolipids through the dibutylstannylene acetals produced the target sulfated glycolipids, 3-sulfate (5a-5j) while stepwise phosphorylation with dibenzyloxy(diisopropylamino) phosphine gave the phosphorylated glycolipids, 3,4-bisphosphate (9e, g, i). The synthetic glycolipids were assayed for their ability to block the adhesion of HL-60 cells to immobilized P-, L- and E-selectin. 1. Dedicated to the memory of Professor Akira Hasagawa. 2. Synthetic studies on sialoglycoconjugates, Part 102. For Part 101, see Y. Makimura, H. Ishida, A. Kondo...