Kiichiro Kawaguchi

Immunomodulating Effects of Flavonoids on Acute and Chronic Inflammatory Responses Caused by Tumor Necrosis Factor α

Flavonoids have beneficial activities which modulate oxidative stress, allergy, tumor growth and viral infection, and which stimulate apoptosis of tumor cells. In addition to these activities, dietary flavonoids are able to regulate acute and chronic inflammatory responses. Here we describe new aspects of regulatory mechanisms by which flavonoids suppress production of tumor necrosis factor-alpha (TNF-alpha) by macrophages, microglial cells and mast cells stimulated with lipopolysaccharide (LPS) and others via toll-like receptors (TLRs), and TNF-alpha-mediated acute and chronic inflammatory responses. Treatment with flavonoids such as luteolin, apigenin, quercetin, genistein, (-)-epigallocatechin gallate, and anthocyanidin resulted in significant downregulation of LPS-elicited TNF-alpha and nitric oxide (NO) production and diminished lethal shock. In chronic diseases, pathogenesis of collagen-induced arthritis (CIA), a mouse model of rheumatoid arthritis which is triggered by TNF-alpha, was improved by the oral administration of flavonoids after the onset of CIA. Here, we discuss that inhibitory effects of flavonoids on acute and chronic inflammation are due to regulation of signaling pathways, including the nuclear factor kappaB (NF-kappaB) activation and mitogen-activated protein (MAP) kinase family phosphorylation. FcetaRI expression by NF-kappaB activation was also reduced by flavonoids; while accumulation of lipid rafts, which is the critical step for signaling, was blocked by flavonoids. The intake of dietary flavonoids reduces acute and chronic inflammation due to blocking receptor accumulation and signaling cascades, and would assist individuals at high-risk from life-style related diseases.

Effects of Antioxidant Polyphenols on TNF-Alpha-Related Diseases

Oxidative stress and inflammatory responses sustained for a long period of time cause many diseases. A proinflammatory cytokine, tumor necrosis factor α (TNF-α), plays a pivotal role in the pathogenesis of chronic and auto-immune diseases. The present review, supplemented by hitherto unpublished data of the authors and their coworkers, shows that the intake of polyphenols contained in natural sources, such as hydroxytyrosol, tyrosol, oleuropein (olives), naringin and hesperidin (Citrus fruits), resveratrol, procyanidins or oligomeric procyanidin (grapes or grape seed extracts), (-)-epigallocatechin gallate (green tea) and quercetin (grapes, green tea) etc., are able to modulate chronic inflammatory diseases, such as type 2 diabetes, rheumatoid arthritis, inflammatory bowel disease, and affect the formation and interaction of advanced glycation end products with their respective receptors. Furthermore, potent activities of fermented grape marc, prepared as a fine lyophilized powder from fresh skin and seeds of a Japanese grape strain (Koshu) and then fermented with Lactobacillus plantarum, are described. Finally, the bioavailability of representative polyphenols will be discussed.

Suppression of lipopolysaccharide-induced tumor necrosis factor-release and liver injury in mice by naringin.

Suppressive effects of naringin on lipopolysaccharide-induced tumor necrosis factor (TNF) release followed by liver injury were investigated. Intraperitoneal (i.p.) treatment with naringin prior to an intravenous (i.v.) challenge of lipopolysaccharide significantly reduced serum TNF levels in a dose-dependent manner and was the most effective when administered 60 min prior to lipopolysaccharide challenge. Treatment with naringin 3 h prior to lipopolysaccharide challenge resulted in complete protection from lipopolysaccharide lethality in D-galactosamine-sensitized mice. Histological estimation revealed that massive cell infiltration followed by severe injury developed in the livers of lipopolysaccharide-treated and D-galactosamine-treated mice unless they had been pretreated with naringin. Appearance of apoptotic cells was also found to decrease by treatment with naringin. Increases in serum levels of aspartate aminotransferase, alanine aminotransferase and creatine kinase, responsible for lipopolysaccharide-induced liver injury, blocked by naringin administration and the levels were nearly to the normal level. These results indicate that action of naringin is mediated through suppression of lipopolysaccharide-induced TNF production.

Biotransformation of progesterone and pregnenolone by plant suspension cultures

Abstract Progesterone was converted to 5α-pregnanolone palmitate in high yield by tobacco ( Nicotiana tabacum var. Bright Yellow) and Sophora angustifolia callus tissues. In Sophora angustifolia callus, 5α-pregnanolone was detected at the same time. The results showed that progesterone undergoes stereospecific reduction of the α,β-unsaturated keto group and esterification. Pregnenolone was also converted to pregnenolone palmitate and 5α-pregnanolone palmitate by tobacco and Sophora angustifolia callus tissues.

Biotransformation of digitoxigenin by ginseng hairy root cultures

Five new compounds (three esters and two glycosides) and seven previously reported compounds were isolated as biotransformation products of digitoxigenin by ginseng hairy root cultures. The new esters and glycosides were elucidated as digitoxigenin stearate, digitoxigenin palmitate, digitoxigenin myristate, 3-epidigitoxigenin beta-D-gentiobioside and digitoxigenin beta-D-sophoroside using 1H and 13CNMR and FAB mass spectral data. Biotransformations involving esterification (of stearic acid, palmitic acid, myristic acid and lauric acid) and glycosylation (of gentiobiose and sophorose) of digitoxigenin have been demonstrated for the first time in the plant cell and tissue cultures. The hairy roots showed high glycosylation ability to the digitoxigenin molecule.

Biotransformation of progesterone by suspension cultures of Digitalis purpurea cultured cells

Abstract It has been shown that the cultured cells of Digitalis purpruea are capable of transforming progesterone (I) to 5α-pregnane-3,20-dione (II), 5α-pregnan-3β-ol-20-one (III), its glucoside (IV), 5α-pregnane-3β,20α-diol (V), its glucoside (VI), 5α-pregnane-3β,20β-diol (VII), its glucoside (VIII), Δ 4 -pregnen-20α-ol-3-one (IX), its glucoside (X), Δ-pregnen-20β-ol-3-one (XI) and its glucoside (XII). 5α-Pregnan-3β-ol-20-one glucoside (IV), 5α-pregnane-3β,20α-diol glucoside (VI), 5α-pregnane-3β,20β-diol glucoside (VIII), Δ 4 -pregnen-20α-ol-3-one glucoside (X) and Δ 4 -pregnen-20β-ol-3-one glucoside (XII) have been found for the first time as new metabolises by plant tissue cultures. A scheme for the biotransformation of progesterone (I) has been proposed, and the reduction and glucosidation activities distinctly have been observed in these cultured cells.

Effects of α-Glucosylhesperidin, a Bioactive Food Material, on Collagen-Induced Arthritis in Mice and Rheumatoid Arthritis in Humans

Hesperidin (Hsp) is an abundant flavonoid in citrus fruits, and the oral administration of Hsp has been recently reported to suppress collagen-induced arthritis in mice. Therefore, we sought to determine whether α-glucosylhesperidin (Hsp-G), which is an Hsp derivative with enhanced water-solubility, is effective on treating arthritis in both mice and humans. Hsp-G was orally administered to mice with collagen-induced arthritis, and its effects were evaluated clinically and histologically. Oral administration of Hsp-G improved collagen-induced arthritis when administered before the onset of arthritis as well as when administered after its onset. A decrease in tumor necrosis factor-α production was found to cause this improvement. In the human study, 19 patients with rheumatoid arthritis (RA) were enrolled in a 12-week double-blind, placebo-controlled trial. Patients were administered beverages containing 3 g Hsp-G (n = 9) or placebo (n = 10) every morning for the duration of the 3-month trial. Additionally, patients received standard therapy from a physician every 4 weeks. As a result, 3 of 9 patients in the Hsp-G group improved, while only 1 of 10 patients in the placebo group improved; this was in accordance with the American College of Rheumatology criteria. The present study revealed that the food material Hsp-G was effective when administered with standard anti-rheumatoid therapy in ameliorating RA in mice and humans without any adverse effects and may improve the quality of life for patients with RA as a complementary/alternative medicine.

Suppressive Effects of the Flavonoids Quercetin and Luteolin on the Accumulation of Lipid Rafts after Signal Transduction via Receptors

Quercetin (QUER) and luteolin (LUTE) are dietary flavonoids capable of regulating the production of cytokines, such as tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6). However, their mechanisms of action are not fully understood. In lipopolysaccharide-triggered (LPS)-triggered signaling via Toll-like receptor 4 (TLR4), QUER and LUTE suppresses not only the degradation of the inhibitor of κB (IκB), with resultant activation of nuclear factor-κB (NF-κB), but also the phosphorylation of p38 and Akt in bone marrow-derived macrophages that have been stimulated with LPS. We report here that, in TNF-α-induced signaling, QUER and LUTE significantly suppressed the production of IL-6 and activation of NF-κB. Accumulation of lipid rafts, the initial step in the signaling pathway, was significantly inhibited when macrophages were treated with QUER or with LUTE prior to exposure to LPS. Similarly, the accumulation of lipid rafts was inhibited by the flavonoids when B cells were activated via the membrane IgM and when T cells were activated via CD3. In contrast, QUER and LUTE did not inhibit the activation of phorbol myristate acetate-induced NF-κB in macrophages. Our observations suggest that QUER and LUTE interact with receptors on the cell surface and suppress the accumulation of lipid rafts that occurs downstream of the activation of the receptors.

Suppression of inflammatory responses after onset of collagen-induced arthritis in mice by oral administration of the Citrus flavanone naringin

Rheumatoid arthritis (RA) is closely related to the pathogenesis of tumor necrosis factor α in lesions. We investigated the suppressive effects of a Citrus flavanone naringin on inflammatory responses in mice with collagen-induced arthritis (CIA), a mouse model for RA. To investigate potential preventive and therapeutic effects of naringin, mice were given naringin orally three times a week from the second immunization with collagen (day 21) and from day 31, when symptoms of CIA had reached a plateau, respectively. In both cases, inflammation-related clinical scores for knee joints were significantly reduced by administration of naringin. Histological analyses demonstrated that representative phenomena, such as damage to interchondral joints, infiltration of inflammatory cells and pannus formation, were significantly depressed by treatment with naringin. In addition, increases in the expression of high-mobility group box-1 protein in the joints of mice with CIA were suppressed by naringin. These results suggest that oral administration of naringin might be effective for treating human patients with RA.

Fermented Grape Marc (FGM): Immunomodulating Properties and its Potential Exploitation in the Treatment of Neurodegenerative Diseases

The onset of neurodegenerative diseases has become more frequent than in the past also in relation to inappropriate dietary habits adopted in the western world. Nutraceuticals are currently investigated in order to prevent or retard the outcome of the so-called diet-related diseases, even including neurodegenerative pathologies. Here, we have in vitro studied the ability of fermented grape marc (FGM) from Negroamaro (N) and Koshu (K) Vitis vinifera to modulate the function of human peripheral blood mononuclear cells (PBMCs). Actually, both FGMs were able to increase the release and the intracellular content of inflammatory and anti-inflammatory cytokines, the induction of FoxP3 (a biomarker of T regulatory cells) and reduce the production of Granzyme B from PBMCs. Since these FGM-induced effects tend to polarize the immune response toward an anti-inflammatory pathway, the potential use of FGMs may represent a valid therapeutic measure to mitigating neuroinflammation in pathologies such as Parkinson disease and Alzheimer disease.