Buxiang Sun

Protective Effects of Oligomers of Grape Seed Polyphenols Against β-Amyloid-Induced Oxidative Cell Death

Abstract: β‐Amyloid (Aβ) is considered to be responsible for the formation of senile plaques that accumulate in the brains of patients with Alzheimers disease (AD). There is compelling evidence supporting the notion that Aβ‐induced cytotoxicity is mediated through the generation of reactive oxygen species (ROS). Recently, considerable attention has been focused on a wide array of non‐vitamin antioxidants present in edible plants that are able to scavenge ROS, thereby protecting against oxidative damage. In this study, we have investigated the possible protective effects of formulated polyphenol oligomers (Oligonol) derived from grape seed extracts on Aβ‐induced oxidative cell death. Rat pheochromocytoma (PC12) cells treated with Aβ exhibited increased accumulation of intracellular ROS and underwent apoptosis, as determined by positive in situ terminal end labeling, decreased mitochondrial membrane potential, and the cleavage of poly(ADP‐ribose)polymerase. Oligonal attenuated Aβ‐induced cytotoxicity, apoptotic features, intracellular ROS accumulation, and lipid peroxidation and increased the cellular glutathione pool. Moreover, Aβ transiently induced the activation of nuclear factor κB in PC12 cells, which was suppressed by pretreatment with Oligonol.

Isoflavone aglycon produced by culture of soybean extracts with basidiomycetes and its anti-angiogenic activity

Soybean extracts (SBE) containing isoflavone glycosides were cultured with Ganoderma lucidum mycelia producing β-glucosidase. The anti-angiogenic effects of the cultivated product, containing rich in genistein, named GCP (genistein combined polysaccharide), were assessed with chick chorioallantoic membranes (CAM) and a mouse dorsal air-sac model. β-Glucosidase produced by the mycelia converted the isoflavone glycosides into aglycons. A test of volunteers showed that serum concentrations of genistein in the subjects treated with GCP (n=4) at 3 h after administration were significantly higher than those in the subjects treated with SBE (n=4). GCP inhibited angiogenesis in CAM, and the activity of GCP was greater than that of SBE. GCP inhibited the formation of new vessels induced by colon carcinoma cells in vivo.

Active hexose correlated compound enhances tumor surveillance through regulating both innate and adaptive immune responses

Active hexose correlated compound (AHCC) is a mixture of polysaccharides, amino acids, lipids and minerals derived from cocultured mycelia of several species of Basidiomycete mushrooms. AHCC has been implicated to modulate immune functions and plays a protective role against infection. However, the potential role of AHCC in tumor immune surveillance is unknown. In this study, C57BL/6 mice were orally administered AHCC or water, followed by tumor cell inoculation. We showed that compared to pure water-treated mice, AHCC treatment significantly delayed tumor development after inoculation of either melanoma cell line B16F0 or lymphoma cell line EL4. Treatment with AHCC enhanced both Ag-specific activation and proliferation of CD4+ and CD8+ T cells, increased the number of tumor Ag-specific CD8+ T cells, and more importantly, increased the frequency of tumor Ag-specific IFN-γ producing CD8+ T cells. Interestingly, AHCC treatment also showed increased cell number of NK and γδ T cells, indicating the role of AHCC in activating these innate-like lymphocytes. In summary, our results demonstrate that AHCC can enhance tumor immune surveillance through regulating both innate and adaptive immune responses.

Oligonol inhibits UVB-induced COX-2 expression in HR-1 hairless mouse skin--AP-1 and C/EBP as potential upstream targets.

Oxidative stress and inflammatory tissue damage are two major events frequently implicated in carcinogenesis. Numerous polyphenolic compounds derived from plants possess antioxidant and anti‐inflammatory activities and are hence effective in preventing cancer. Oligonol is a polyphenol formulation enriched with catechin‐type oligomers. As an initial approach to assess the chemopreventive potential of oligonol, we have determined its effects on inflammatory as well as oxidative damage in mouse skin irradiated with UVB. Topical application of oligonol onto the dorsal skin of male HR‐1 hairless mice 30 min prior to UVB exposure diminished epidermal hyperplasia and formation of 4‐hydroxynonenal, a biochemical hallmark of lipid peroxidation. Topical application of oligonol also significantly inhibited UVB‐induced cyclooxygenase (COX‐2) expression in mouse skin. Oligonol diminished the DNA binding of activator protein‐1 (AP‐1) and CCAAT/enhancer binding protein (C/EBP), and the expression of C/EBPδ in mouse skin exposed to UVB. Our study also revealed that oligonol attenuated UVB‐induced catalytic activity as well as expression of p38 mitogen‐activated protein (MAP) kinase. Moreover, UVB‐induced phosphorylation of another upstream kinase Akt was attenuated by oligonol. Taken together, oligonol showed antioxidative and anti‐inflammatory effects in UVB‐irradiated mouse skin by inhibiting COX‐2 expression via blockade of the activation of AP‐1 and C/EBP, and upstream kinases including p38 MAP kinase and Akt.

Active hexose correlated compound activates immune function to decrease bacterial load in a murine model of intramuscular infection

BACKGROUND Infection is a serious, costly, and common complication of surgery and constitutes the principal cause of late death in patients undergoing surgery. The objective of this study was to clarify the mechanisms by which active hexose correlated compound (AHCC) increases survival in a murine model of intramuscular infection. METHODS Food-deprived mice receiving either AHCC or excipient were infected with bacteria. Kinetics of bacterial load, white blood cell counts, cytokine levels, and antibody levels were compared between groups. RESULTS AHCC-treated mice had reduced bacterial load at day 5 and cleared bacteria entirely at day 6. Levels of interleukin-12, tumor necrosis factor-alpha, and interleukin-6 peaked earlier in this group (day 3) compared with controls (day 5). Increased percentages of peripheral lymphocytes and monocytes and decreased numbers of polymorphonuclear cells were detected in the AHCC group. CONCLUSIONS AHCC appears to induce an early activation of the immune response, leading to an effective clearance of bacteria and rapid recovery.

Inhibition of human breast cancer growth by GCP™ (genistein combined polysaccharide) in xenogeneic athymic mice: involvement of genistein biotransformation by β-glucuronidase from tumor tissues

The role of beta-glucuronidase in genistein biotransformation was investigated in a human breast cancer MDA-MB-231 xenogeneic athymic mouse model. Genistein combined polysaccharide (GCP), a genistein aglycone rich functional food supplement was used in these experiments. Tumor-bearing mice were subjected to oral administration of GCP for 28 days. GCP treatment significantly inhibited tumor growth. Induction of apoptosis by GCP treatment was related to activation of cleavage of poly(ADP-ribose)polymerase, induction of the p21 protein expression and reduction of cyclin B1 expression in the tumor tissues. Genistein exists as a glucuronide conjugate in normal organ tissues, and the conjugated genistein lacks the physiological activity of the aglycone. Tumor tissues contain large amounts of beta-glucuronidase, the enzyme that converts the genistein beta-glucuronide conjugate into genistein aglycone. The resulting genistein aglycone exerts its chemopreventive activities, including the induction of apoptosis in tumor tissues, and, finally, leads to tumor growth inhibition.

Inhibitory effects of oligonol on phorbol ester-induced tumor promotion and COX-2 expression in mouse skin: NF-κB and C/EBP as potential targets

Plant polyphenols possess anti-oxidant and anti-inflammatory activities and are hence potential candidates for preventing cancer. The present study was aimed at evaluating the anti-inflammatory and anti-tumor promoting activity of oligonol, a formulation of catechin-type oligomers, in mouse skin stimulated with a proto-type tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Pretreatment of mouse skin with oligonol significantly inhibited TPA-induced expression of cyclooxygenase-2 (COX-2). Oligonol diminished nuclear translocation and DNA binding of nuclear factor-kappaB (NF-kappaB) via blockade of phosphorylation and subsequent degradation of IkappaB alpha in TPA-treated mouse skin. Moreover, oligonol suppressed TPA-induced DNA binding of CCAAT/enhancer-binding protein (C/EBP) in mouse skin. Oligonol pretreatment also attenuated the phosphorylation and/or catalytic activities of extracellular signal-regulated protein kinase-1/2 (ERK1/2) and p38 mitogen-activated protein (MAP) kinase. Moreover, p38 MAP kinase inhibitor SB203580, but not the MEK inhibitor U0126, negated TPA-induced DNA binding of C/EBP. In addition, oligonol reduced the incidence and the multiplicity of papillomas and squamous cell carcinomas in 7,12-dimethylbenz[a]anthracene (DMBA)-initiated and TPA-promoted mouse skin, and prolonged the survival of tumor-bearing mice. Pretreatment with oligonol diminished the levels of proliferating cell nuclear antigen and expression of COX-2 in papillomas and carcinomas, respectively, as compared to DMBA plus TPA treatment alone. Taken together, the above findings suggest that oligonol inhibits TPA-induced COX-2 expression by blocking the activation of NF-kappaB and C/EBP via modulation of MAP kinases and suppresses chemically induced mouse skin tumorigenesis.

Oral Administration of Active Hexose Correlated Compound Enhances Host Resistance to West Nile Encephalitis in Mice

West Nile virus (WNV) poses a serious threat to public health, especially to the elderly and the immuno-compromised. Neither vaccines nor treatments are available for humans. Active hexose correlated compound (AHCC) is an extract of Lentinula edodes of the Basidiomycete family of fungi rich in alpha-glucans. In this study, we evaluated the effect of AHCC on host susceptibility in the murine model of WNV infection. Mice orally administered with AHCC (600 mg/kg) every other day for 1 wk before and at d 1 and 3 postinfection were assessed using viremia levels, survival rate, and protective immunity. AHCC administration in young (6- to 8-wk-old) mice attenuated viremia and mortality following lethal WNV infection. WNV-specific IgM and IgG production and gammadelta T cell expansion were also enhanced in these mice. Aged (21- to 22-mo-old) mice were more susceptible to WNV infection than young mice, partially due to the dysfunction of gammadelta T cell subsets. AHCC administration in aged mice enhanced the protective Vgamma1(+) T cell response as well as WNV-specific IgG but not IgM antibodies production. AHCC administration in aged mice attenuated viremia levels but led to no difference in mortality rate. Overall, our data suggests that AHCC enhances protective host immune responses against WNV infection in young and aged mice. Dietary supplementation with AHCC may be potentially immunotherapeutic for WNV-susceptible populations.

The effect of active hexose correlated compound in modulating cytosine arabinoside-induced hair loss, and 6-mercaptopurine- and methotrexate-induced liver injury in rodents.

BACKGROUND Active hexose correlated compound (AHCC) (a mixture of polysaccharides, amino acids, lipids and minerals derived from cultured mycelia of a Basidiomycete mushroom, Lentinula edodes) was used to assess amelioration of alopecia (hair loss) caused by cytosine arabinoside (Ara-C) and modulation of liver injury caused by single doses 6-mercaptopurine (6-MP) plus methotrexate (MTX). METHODS Follicular integrity and hair growth was assessed in male and female SD neonatal rats (8 days old) treated with a single dose of Ara-C (30 mg/kg/day, i.p.) and AHCC (500 mg/kg/day, p.o.) for 7 consecutive days. The side effects of a single oral dose of 6-MP (2.5mg/kg body weight) plus MTX (30 mg/kg body weight) and their amelioration by treatment with AHCC (1000 mg/kg body weight) for 28 days were assessed in male ddY mice (8 weeks old). RESULTS Of the Ara-C treated rats 71.4% showed severe alopecia and 28.6% showed moderate alopecia. However, the AHCC (p.o.)-treated Ara-C group was significantly protected from alopecia. Ara-C treated rats had profound loss of hair follicles but the Ara-C plus AHCC-treated group had mild losses of follicles. AHCC supplementation to the 6-MP- and MTX-treated mice significantly increased body weight, erythrocytes, leukocytes and serum albumin, improved liver hypertrophy and degeneration, normalized the activities of serum glutamic oxaloacetic transaminase (sGOT) and serum glutamic pyruvic transaminase (sGPT), and enhanced liver drug-metabolizing enzymes. CONCLUSION Co-administration of AHCC significantly reduced the side effects associated with Ara-C, 6-MP and MTX. However, the molecular mechanism for AHCC activity and its clinical integrity for use needs defining.

A natural immune modulator attenuates stress hormone and catecholamine concentrations in polymicrobial peritonitis.

BACKGROUND Activated hexose correlated compound (AHCC), derived from shiitake mushrooms, increases resistance to infection in immunocompromised hosts with positive effects on dendritic cells, natural killer cell function and interleukin 12 production. It may also be attenuating the systemic inflammatory response by regulating the secretion of cortisol and norepinephrine (NE). METHODS Female Swiss-Weber mice were pretreated with AHCC (Amino Up Chemical Co., Sapporo, Japan) or water by gavage for 10 days before undergoing cecal ligation and puncture (CLP). Peritoneal exudate cells and blood samples were harvested at 4 hours and 24 hours following CLP. Plasma and peritoneal concentrations of cortisol and NE were obtained using enzyme-linked immunosorbent assay. Peritoneal bacteria were quantified by colony counts after 4 hours and 24 hours. Significance was denoted by a p < 0.05. RESULTS Plasma and peritoneal cortisol concentrations were increased 4 hours after CLP compared with normal controls, with no difference between the pretreated groups. Concentrations of cortisol decreased from 4 hours to 24 hours after CLP with AHCC (plasma, p = 0.009; peritoneal, p < 0.001), and peritoneal cortisol at 24 hours was lower with AHCC as compared with water (p = 0.028). There was no change in plasma or peritoneal NE concentrations at 4 hours. At 24 hours, higher concentrations of NE were detected in both plasma and peritoneal fluid, with lower plasma concentrations in those gavaged with AHCC (p = 0.015). There was no significant difference in peritoneal bacteria counts. CONCLUSION Enhanced immune function observed with AHCC could be caused by attenuated concentrations of stress hormones and catecholamines.