Green Chemistry for Crosslinking Biopolymers: Recent Advances in Riboflavin-Mediated Photochemistry.

Riboflavin (RF), which is also known as vitamin B2, is a water-soluble vitamin. RF is a nontoxic and biocompatible natural substance. It absorbs light (at wavelengths of 380 and 450 nm) in the presence of oxygen to form reactive singlet oxygen (1O2). The generated singlet oxygen acts as a photoinitiator to induce the oxidation of biomolecules, such as amino acids, proteins, and nucleotides, or to initiate chemical reactions, such as the thiol-ene reaction and crosslinking of tyramine and furfuryl groups. In this review, we focus on the chemical mechanism and utilization of the photochemistry of RF, such as protein crosslinking and hydrogel formation. Currently, the crosslinking method using RF as a photoinitiator is actively employed in ophthalmic clinics. However, a significant broadening is expected in its range of applications, such as in tissue engineering and drug delivery.

Enhancing the Antioxidant Activities of Wines by Addition of White Rose Extract.

White rose petal extract (WRE) contains large amounts of phenolic compounds and is considered edible. In this study, red and white wines were prepared by the addition of WRE (0.10% or 0.25% (w/v)), followed by fermentation at 25°C for 15 days. The fermentation profiles, colors, sensory test results, and antioxidant activities of the wines were compared. As reported herein, the fermentation profiles of the pH, CO2 production rate, and final ethanol concentration were not affected by the addition of WRE, but a slow consumption rate of sugar was observed in 0.25% WRE-added wine. In contrast, the total polyphenol concentrations in WRE-added wines increased significantly (p < 0.05) in a dose-dependent manner, resulting in appreciable enhancement of the antioxidant activities of the wines. Chromaticity tests showed slight changes in the redness and yellowness, but sensory tests showed that the overall flavor qualities of the WRE-added wines were acceptable to the panels. This study demonstrates that addition of WRE to wine confers beneficial health effects and this treatment results in better outcome in white wine.

Soy milk digestion extract inhibits progression of prostate cancer cell growth via regulation of prostate cancer­specific antigen and cell cycle-regulatory genes in human LNCaP cancer cells.

Soy milk, which is produced from whole soybeans, contains a variety of biologically active components. Isoflavones are a class of soy-derived phytoestrogens with beneficial effects, among which genistein (GEN) has been previously indicated to reduce the risk of prostate cancer. The present study evaluated the effects of soy milk digestion extract (SMD) on the progression of prostate cancer via the estrogen receptor (ER)ß in human LNCaP prostate cancer cells. To evaluate the effects of SMD (daizein, 1.988 mg/100g, glycitein, 23.537 mg/100 g and GEN, 0.685 mg/100g) on cell proliferation, LNCaP cells were cultured in media containing vehicle (0.1% dimethyl sulfoxide), 17ß­estradiol (E2; 2.7x10­7 mg/ml), GEN (2.7x10-2 mg/ml) of SMD (total aglycon concentration, 0.79 mg/ml), after which the cell viability was examined using an MTT assay. The cell viability was significantly elevated by E2 (by 45±0.18%), while it was markedly reduced by GEN (73.2±0.03%) or SMD (74.8±0.09%). Semi­quantitative reverse transcription polymerase chain reaction analysis was performed to assess the mRNA expression levels of target genes, including ERß, prostate cancer­specific antigen (PSA) and cell cycle regulators p21, Cyclin D1 and cyclin-dependent kinase (CDK)4. The expression of ERß was almost completely diminished by E2, whereas it was significantly elevated by SMD. In addition, the expression levels of PSA were considerably reduced by SMD. The expression of p21 was significantly elevated by SMD, while it was markedly reduced by E2. Of note, the expression levels of Cyclin D1 and CDK4 were considerably elevated by E2, while being significantly reduced by GEN and SMD. All of these results indicated that SMD may inhibit the proliferation of human prostate cancer cells via regulating the expression of ERß, PSA, p21, Cyclin D1 and CDK4 in an ER-dependent manner.

Antimicrobial activities of ethanol and butanol fractions of white rose petal extract.

White rose (Rosa hybrida) petals were extracted with ethanol (EtOH) or butanol (BuOH), and tested for their antimicrobial activities against two species of Gram-positive bacteria, six species of Gram-negative bacteria, and two species of fungi. On in vitro antimicrobial assays, Helicobacter pylori and Propionibacterium acnes were highly susceptible to white rose petal extract (WRPE)-EtOH and WRPE-BuOH, leading to minimal inhibitory concentrations of 100 and 10 µg/mL for H. pylori and 400 and 40 µg/mL for P. acnes, respectively. In in vivo experiments, C57BL/6 mice were infected with H. pylori by intragastric inoculation (1 × 10(8) CFU/mouse) 3 times, and orally treated twice a day for 14 days with WRPE-EtOH and WRPE-BuOH. On a CLO kit assay, 200 mg/kg of WRPE-EtOH fully eliminated the bacteria from the gastric mucosa, and the effect of 100 mg/kg of ethanol fraction was similar to pantoprazole (30 mg/kg), displaying 75% elimination. WRPE-BuOH was more effective, exhibiting 75% elimination at 20 mg/kg. The CLO test results were confirmed by bacterial identification. WRPE-EtOH and WRPE-BuOH inhibited the growth of various bacteria and fungi, and in particular, they effectively killed H. pylori and eliminated the bacteria from the mouse stomach. The results indicate that WRPE-EtOH and WRPE-BuOH could be good candidates for the elimination of H. pylori.

Low-FODMAP formula improves diarrhea and nutritional status in hospitalized patients receiving enteral nutrition: a randomized, multicenter, double-blind clinical trial.

BACKGROUND: Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) are poorly absorbed, short-chain carbohydrates that play an important role in inducing functional gut symptoms. A low-FODMAP diet improves abdominal symptoms in patients with inflammatory bowel disease and irritable bowel syndrome. However, there were no study for the effect of FODMAP content on gastrointestinal intolerance and nutritional status in patients receiving enteral nutrition (EN). METHODS: In this randomized, multicenter, double-blind, 14-day clinical trial, eligible hospitalized patients receiving EN (n = 100) were randomly assigned to three groups; 84 patients completed the trial (low-FODMAP EN, n = 30; moderate-FODMAP EN, n = 28; high-FODMAP EN, n = 26). Anthropometric and biochemical parameters were measured; stool assessment was performed using the King's Stool Chart and clinical definition. RESULTS: Baseline values were not significantly different among the three groups. After the 14-day intervention, diarrhea significantly improved in the low-FODMAP group than in the moderate- and high-FODMAP groups (P < 0.05). King's Stool scores in diarrhea subjects were significantly and steadily reduced in the low-FODMAP group compared with the other two groups (P for time and EN type interaction <0.05). BMI increased significantly in the low- and high-FODMAP groups during the intervention (P < 0.05 for both), and showed a trend toward increasing in the moderate-FODMAP group (P < 0.10). Serum prealbumin increased significantly in all groups by 14-day; by 3-day, it had increased to the levels at 14-day in the low-FODMAP group. At 14-day, serum transferrin had increased significantly in the moderate-FODMAP group. In addition, subjects were classified by final condition (unimproved, normal maintenance, diarrhea only improved, constipation only improved, and recurrent diarrhea/constipation improved). Seventy-five percent of the diarrhea improved group consumed the low-FODMAP EN formula. 38.5 and 46.2% of recurrent diarrhea/constipation improved group consumed the low- and moderate-FODMAP EN respectively. BMI significantly increased in all groups except the unimproved. Prealbumin levels significantly increased in the diarrhea-improved and recurrent diarrhea/constipation groups at 3-day and continued by 14-day, and in the constipation-improved group at 14-day. Transferrin levels significantly increased in the diarrhea-improved and recurrent diarrhea/constipation groups at 14-day. CONCLUSION: Low-FODMAP EN may improve diarrhea, leading to improved nutritional status and facilitating prompt recovery from illness.

Extraction conditions of white rose petals for the inhibition of enzymes related to skin aging.

In order to assess inhibitory potentials of white rose petal extracts (WRPE) on the activities of enzymes related to dermal aging according to the extraction conditions, three extraction methods were adopted. WRPE was prepared by extracting dried white rose (Rosa hybrida) petals with 50% ethanol (WRPE-EtOH), Pectinex® SMASH XXL enzyme (WRPE-enzyme) or high temperature-high pressure (WRPE-HTHP). In the inhibition of matrix metalloproteinase-1, although the enzyme activity was fully inhibited by all 3 extracts at 100 µg/mL in 60 min, partial inhibition (50-70%) was achieved only by WRPE-EtOH and WRPE-enzyme at 50 µg/mL. High concentrations (≥250 µg/mL) of all 3 extracts markedly inhibited the elastase activity. However, at low concentrations (15.6-125 µg/mL), only WRPE-EtOH inhibited the enzyme activity. Notably, WRPE-EtOH was superior to WRPE-enzyme and WRPE-HTHP in the inhibition of tyrosinase. WRPE-EtOH significantly inhibited the enzyme activity from 31.2 µM, reaching 80% inhibition at 125 µM. In addition to its strong antioxidative activity, the ethanol extract of white rose petals was confirmed to be effective in inhibiting skin aging-related enzymes. Therefore, it is suggested that WRPE-EtOH could be a good candidate for the improvement of skin aging such as wrinkle formation and pigmentation.

Erratum: Synergistic anti-inflammatory effects of Laminaria japonica fucoidan and Cistanche tubulosa extract.

[This corrects the article on p. 91 in vol. 28, PMID: 22787482.].

The anti-aging properties of a human placental hydrolysate combined with dieckol isolated from Ecklonia cava.

BACKGROUNDS: In the present study, we aimed to examine the anti-aging properties of human placental hydrolysate (HPE) and dieckol (DE) from Ecklonia cava against free radical scavenging, muscle hypertrophy-related follistatin mRNA expression, amelioration of cognition-related genes and proteins, inhibition of collagenase-regulating genes, and elastinase activity. METHODS: The anti-aging effects were examined in human fibroblast (CCD986sk), mouse myoblast (C2C12), and neuroblastoma (N2a) cell models, by employing various assays such as 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) scavenging, hydroxyl radical-mediated oxidation, quantitative real-time polymerase chain reaction, enzyme activity, and immunocytochemistry observation. RESULTS: Our results show that HPE combined with DE (HPE:DE) strongly scavenged DPPH radicals and protected proteins against degradation by hydroxyl radical attack. HPE:DE effectively inhibited matrix metalloproteinase-1 expression, protein kinase C alpha expression, and elastinase activity. Furthermore, HPE:DE improved the expression of cognition-related genes (choline acetyltransferase and vesicular acetylcholine transporter). These events may proactively contribute to retard the aging processes and the abrupt physiological changes probably induced by mitochondrial dysfunction with aging. CONCLUSIONS: Based on these findings, we conclude that the combined treatment of HPE:DE may be useful for anti-aging therapy in which the accumulation of oxidative damage is the main driving force.

Protective effects of N-acetyl-L-cysteine in human oligodendrocyte progenitor cells and restoration of motor function in neonatal rats with hypoxic-ischemic encephalopathy.

Objective. Since oligodendrocyte progenitor cells (OPCs) are the target cells of neonatal hypoxic-ischemic encephalopathy (HIE), the present study was aimed at investigating the protective effects of N-acetyl-l-cysteine (NAC), a well-known antioxidant and precursor of glutathione, in OPCs as well as in neonatal rats. Methods. In in vitro study, protective effects of NAC on KCN cytotoxicity in F3.Olig2 OPCs were investigated via MTT assay and apoptotic signal analysis. In in vivo study, NAC was administered to rats with HIE induced by hypoxia-ischemia surgery at postnatal day 7, and their motor functions and white matter demyelination were analyzed. Results. NAC decreased KCN cytotoxicity in F3.Olig2 cells and especially suppressed apoptosis by regulating Bcl2 and p-ERK. Administration of NAC recovered motor functions such as the using ratio of forelimb contralateral to the injured brain, locomotor activity, and rotarod performance of neonatal HIE animals. It was also confirmed that NAC attenuated demyelination in the corpus callosum, a white matter region vulnerable to HIE. Conclusion. The results indicate that NAC exerts neuroprotective effects in vitro and in vivo by preserving OPCs, via regulation of antiapoptotic signaling, and that F3.Olig2 human OPCs could be a good tool for screening of candidates for demyelinating diseases.

Comparative analysis of anti-Helicobacter pylori activities of FEMY-R7 composed of Laminaria japonica and Oenothera biennis extracts in mice and humans.

Helicobacter pylori-eliminating effects of FEMY-R7, composed of Laminaria japonica and Oenothera biennis extracts, were investigated in mice and humans. Male C57BL/6 mice were infected with the bacteria by intragastric inoculation (1×10(9) CFU/mouse) 3 times at 2-day intervals, and simultaneously, orally treated twice a day with total 20, 64 or 200 mg/kg/day FEMY-R7 for 2 weeks. In Campylobcter-like organism (CLO)-detection tests on gastric mucosa and feces, FEMY-R7 reduced the urease-positive reactivity in a dose-dependent manner; i.e., the positivity ratios were decreased to 70, 20, and 10% for gastric mocosa and to 80, 50, and 20% for feces. In a clinical sudy, human subjects, confirmed to be infected with Helicobacter pylori, were orally administered twice a day with capsules containing total 100, 320 or 1,000 mg/man/day FEMY-R7 (matching doses for 20, 64 or 200 mg/kg/day, respectively, in mice from a body surface area-based dose translation) for 8 weeks. FEMY-R7 decreased the positivity ratios in feces to 70, 40, and 30%, respectively. In bacterial culture, H. pylori was identified from the CLO-positive stools of mice and humans. The bacterial identification ratios exhibited a good correlation between the matching doses in mice and humans. It is suggested that FEMY-R7 could be a promising functional food without tolerance as an adjunct to reduce the dosage of antibiotics for the treatment of recurrent H. pylori infection.

Isoflavone supplementation influenced levels of triglyceride and luteunizing hormone in Korean postmenopausal women.

We conducted a double-blind, randomized, placebo-controlled trial to evaluate the effects of soy-derived isoflavone on blood glucose, lipid profiles, and sex hormones related to cardiovascular disease in Korean postmenopausal women. One hundred thirteen postmenopausal women were recruited from the Seoul metropolitan area. To confirm postmenopausal and gynecologic status, the subjects were clinically examined by a gynecologist using ultra sound and X-ray. Finally, 85 postmenopausal women whose follicle-stimulating hormone (FSH) levels were higher than 40 IU/ml were enrolled. Subjects received either 70 mg isoflavone or placebo capsules daily for 12 weeks. As a result, the values of fasting glucose, insulin and HOMA-IR, as well as those of TC, LDL-C, HDL-C and FFA, were not different between the groups after supplementation. However, triglyceride (TG) levels in the treatment group decreased significantly compared with those of the placebo group (p = 0.0215). The levels of luteinizing hormone (LH) significantly decreased in the treatment group (p = 0.027); however, the levels of FSH, estrone and estradiol were not changed after intervention. In conclusion, isoflavone supplement of 70 mg/day for 12 weeks decreased blood levels of TG and LH in Korean postmenopausal women.

Synergistic anti-inflammatory effects of Laminaria japonica fucoidan and Cistanche tubulosa extract.

The anti-inflammatory effects of fuciodan and Cistanche tubulosa (CT) extract were investigated in vitro macrophage culture system and in vivo carrageenan-induced air pouch inflammation model. CT extract inhibited nitric oxide production from activated RAW 264.7 macrophage cells, while fucoidan was inactive. In vivo air pouch inflammation model, carrageenan-induced vascular exudation and increased nitric oxide and prostaglandin E(2) concentrations in the exudates were synergistically suppressed by co-administration of fucoidan or CT extract. Moreover, tissue inflammation was substantially attenuated by the combinational therapy. However, there was no synergistic effect against the inflammatory cell infiltration, although fucoidan and CT extract each markedly reduced the cell numbers. Therefore, it is suggested that fucoidan blocks infiltration of inflammatory cells, while CT extract inhibits activation of the cells, and that their combinational treatment could be a promising candidate for the relief of various types of inflammation.

Anti-inflammatory effects of Houttuynia cordata supercritical extract in carrageenan-air pouch inflammation model.

Anti-inflammatory effects of Houttuynia cordata supercritical extract (HSE) were investigated in rat carrageenan-air pouch model. Oral administration of HSE (50-200 mg/kg) suppressed carrageenan-induced exudation and albumin leakage, as well as inflammatory cell infiltration at a high dose (200 mg/kg). Intraperitoneal injection of dexamethasone (2 mg/kg) only decreased exudation and cell infiltration, while indomethacin (2 mg/kg, i.p.) reduced exudate volume and albumin content without influence on the cell number. HSE lowered tumor-necrosis factor-α (TNF-α) and nitric oxide (NO), as well as prostaglandin E(2) (PGE(2)). Dexamethasone only reduced TNF-α and NO, while indomethacin decreased PGE(2). The results indicate that HSE exhibits anti-inflammatory effects by inhibiting both TNF-α-NO and cyclooxygenase-2-PGE(2) pathways.

Arginine vasopressin (AVP) expressional changes in the hypothalamic paraventricular and supraoptic nuclei of stroke-prone spontaneously hypertensive rats.

Arginine vasopressin (AVP) is a neuropeptide with vasoconstrictive, antidiuretic, cardiovascular regulative and hepatic glycogenolysis effects, that also affects other behaviors including modulating learning. A number of studies on AVP regulation have been conducted in various metabolic diseases (disorders). In this study, the immunoreactivities of AVP in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) and mRNA expressions in the hypothalamus were investigated by immunohistochemistry and quantitative real-time PCR (RT-qPCR) in stroke-prone spontaneously hypertensive rats at different ages (i.e., at postnatal months [PM] 1, 8, and 12). Blood glucose levels in the PM 8 group were higher than in the other groups. However, cresyl violet positive neurons were detected in the PVN and SON of all animals, and numbers of cresyl violet positive neurons were similar in all aged groups. In addition, AVP immunoreactivity was detected in the PVN and SON of all age groups, and AVP immunoreactivity and mRNA expression levels were found to be increased in proportion to age by immunohistochemistry and RT-qPCR. These results suggest that the diabetic condition is temporally generated after hypertension has developed. Furthermore, our findings suggest that increased AVP expressions in the hypothalamic PVN and SON are associated with hypertension by age.

Soy isoflavones mitigate long-term femoral and lumbar vertebral bone loss in middle-aged ovariectomized mice.

We evaluated the protective effects of soy isoflavones (SIF) against osteoporosis in middle-aged ovariectomized (OVX) mice. SIF (30 mg/kg or 60 mg/kg) or 17beta-estradiol (E(2)) was administered to OVX mice for 4 months after bilateral ovariectomy. We observed the biochemical markers of bone turnover, e.g., alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP), in serum. We also observed the bone mineral density (BMD) in femurs and lumbar vertebrae. In addition, we examined trabecular bone and interstitial cells in the femur using hematoxylin and eosin staining. The decrease in ALP levels and the increase in TRAP levels normally resulting from ovariectomy were suppressed by administration of 60 mg/kg SIF or E(2). Administration of 60 mg/kg SIF or E(2) also maintained the BMD, trabecular bone, and interstitial cells in OVX mice compared to those in pre-OVX mice. These results suggest that 60 mg/kg SIF effectively mitigates ovariectomy-induced osteoporosis in middle-aged mice.

Effects of soy phytoestrogens on reference memory and neuronal cholinergic enzymes in ovariectomized rats.

The effects of soy phytoestrogens on Morris water maze (MWM) performance and neuronal cholinergic enzyme activities and immunoreactivity were studied in ovariectomized (OVX) rats. The rats were assigned to four groups fed control diet (CD), 3.9 mg/kg 17beta-estradiol diet (E2), 263.4 mg/kg soy phytoestrogens diet (SP1), and 526.9 mg/kg soy phytoestrogens diet (SP2). In the MWM task, escape latency and path length were significantly less in the E2 and SP2 groups than in the CD group on the second day. Choline acetyltransferase (ChAT) activity in the cerebral cortex and ChAT immunoreactivity in the diagonal band of Broca were significantly greater in the E2, SP1, and SP2 groups than in the CD group. Acetylcholinesterase activity in the hippocampus in the E2, SP1, and SP2 groups was significantly lower than in the CD group. This study suggests that soy phytoestrogens affect the reference memory and neuronal cholinergic system in OVX rats.

Evaluation of enhanced hygroscopicity, bifidogenicity, and anticariogenicity of enzymatically synthesized beta-galactosyl-trehalose oligosaccharides.

beta-Galactosyl-trehalose oligosaccharides (beta-GTOs) were enzymatically prepared as a mixture of 6-beta-galactosyl-trehalose (1) and 4-beta-galactosyl-trehalose (2) with a 9:1 ratio (w/w). The beta-GTO mixture showed a highly enhanced hygroscopicity as compared to those of trehalose and other sugars used. At 72 h of incubation under 90% relative humidity and room temperature, it had a large increase in weight due to its moisture absorption, which was five times larger than that of trehalose, 1.9 times larger than that of sucrose, and 1.5 times larger than that of maltotriose. It was very effective in the growth promotion of Bifidobacteria, such as Bifidobacterium longum and Bifidobacterium bifidum, which was better than the growth promotion in the cases of trehalose and galactooligosaccharide. It also showed a highly anticariogenic property; it had only 10% cell proliferation of Streptococcus sobrinus for that of the sucrose control and 60% inhibition of insoluble glucan synthesis. Its effectiveness of inhibition was two and 1.5 times better than that of trehalose and one and two times than xylitol, respectively, against cell growth and glucan synthesis. Conclusively, the functionality of the beta-GTO in terms of hygroscopicity, bifidogenicity, and anticariogenicity was considerably improved as compared to that of trehalose. It is thus suggested that the beta-GTO might be applied as an effective humectant and prebiotic substitute with enhanced noncariogenicity in food applications.

Calbindin D-28k immunoreactivity increases in the hippocampus after long-term treatment of soy isoflavones in middle-aged ovariectomized and male rats.

This article investigates the long-term effects of soybean isoflavones (ISO) on the changes of calbindin D-28k (CB) immunoreactivity in the hippocampus in middle-aged ovariectomized female rats as well as middle-aged control female and male rats to identify any correlation between calcium and phytoestrogens. In the CA1 region, CB immunoreactivity in the ovariectomized females was similar to that of the control females, whereas CB immunoreactivity in the males was significantly lower than that of the control females. In the dentate gyrus, CB immunoreactivity in the ovariectomized females and males was significantly lower than that of the control females. CB immunoreactivity in all groups was increased dose-dependently after ISO treatment in the CA1 region and dentate gyrus. This result suggests that ISO treatment enhances the expression of CB immunoreactivity in the hippocampus in the middle-aged rats.

Comparison of alpha-synuclein immunoreactivity and protein levels in ischemic hippocampal CA1 region between adult and aged gerbils and correlation with Cu,Zn-superoxide dismutase.

In this study, we examined changes in the level and immunoreactivity of alpha-synuclein in the hippocampal CA1 region of adult (6 months old) and aged (24 months old) gerbils after 5 min of transient forebrain ischemia. The delayed neuronal death of CA1 pyramidal cells in adult gerbils was severer than that in aged gerbils 4 days after ischemia/reperfusion. Alpha-synuclein immunoreactivity in the CA1 region of adult and aged gerbils significantly changed after ischemia. In control animals, alpha-synuclein immunoreactivity and level in the aged-gerbil CA1 region were higher than those in the adult-gerbil CA1 region. In both adult and aged gerbils, alpha-synuclein immunoreactivity and level started to increase 3h after ischemia, and they were highest 1 day after ischemia. Thereafter, alpha-synuclein immunoreactivity and level decreased with time after ischemia. We also observed the effects of Cu,Zn-superoxide dismutase (SOD1) on ischemic damage using the Pep-1 transduction domain. Alpha-synuclein level in the CA1 region was lower in Pep-1-SOD1-treated adult and aged gerbils than in vehicle-treated adult and aged gerbils. We conclude that neuronal loss in the hippocampal CA1 region of adult gerbils was more prominent than that in aged gerbils 4 days after ischemia/reperfusion. The higher level of alpha-synuclein in the aged-gerbil CA1 region than that in the adult-gerbil CA1 region may be associated with the earlier induction of reactive oxygen species, and Pep-1-SOD1 potentially and reversibly inhibits the accumulation of alpha-synuclein in the CA1 region after transient ischemia.

Soybean isoflavones alter parvalbumin in hippocampus of mid-aged normal female, ovariectomized female, and normal male rats.

AIM: To investigate the long-term effect of soybean isoflavones on changes in parvalbumin (PV) immunoreactivity in the hippocampus in normal female, ovariectomized (OVX) female and normal male rats. METHODS: Ten-month-old rats were assigned to one of 9 groups (n = 7 in each group) based on body weight using a randomized complete-block design. The groups were: control diet-treated females, OVX females, and males; 0.3 g/kg isoflavone-treated females, OVX females, and males; and 1.2 g/kg isoflavone-treated females, OVX females, and males. The PV immunostaining was conducted by using the standard avidin-biotin complex method. RESULTS: PV immunoreactivity and the number of PV-immunoreactive neurons in all the groups after isoflavone treatment were significantly changed in the hippocampal CA1 region and in the dentate gyrus, but not in the hippocampal CA2/3 region. PV immunoreactivity and the number of PV-immunoreactive neurons in the control diet OVX females were similar to those in the control diet, and were greater than those in the control diet normal females. PV immunoreactivity and the number of PV-immunoreactive neurons in all the isoflavone-treated groups decreased dose-dependently after isoflavone treatment. CONCLUSION: Long-term administration of isoflavones may induce a reduction of PV in interneurons in the hippocampal CA1 region and in the dentate gyrus. The reduction of PV in these regions suggests that the long-term administration of isoflavones may cause a change in calcium homeostasis in the hippocampal CA1 region and in the dentate gyrus.