Effects of Choto-san and its related constituents on endogenous antioxidant systems

Oxidative stress and genotoxicity of co-exposure to chlorpyrifos and aflatoxin B1 in HepG2 cells

Chlorpyrifos (CPF) and aflatoxin B₁ (AFB₁) are each known to adversely affect hepatic tissue individually, but their combined hepatic effects have never been previously investigated. HepG2 cell viability, oxidative status, and genetic impairment were examined after exposing HepG2 cells to: (1) CPF alone, (2) AFB₁ alone, and (3) CPF and AFB₁ combined (20:1). CPF exposure decreased cell viability, reduced glutathione (GSH) content, and superoxide dismutase (SOD) activity but increased both glutathione peroxidase (GPx) and paraoxonase 1 activity. AFB₁ exposure decreased cell viability and GSH content but increased reactive oxygen species (ROS) production. CPF and AFB₁ combined exposure decreased GSH content (p < 0.05) further over individual CPF and AFB₁ exposures. Induction of micronucleus formation was detected in AFB₁-treated cells but undetected in both CPF and combination-treated cells. In conclusion, cytotoxic effects caused by combined exposure were antagonistic, as shown by a combination index value of 1.67. Although no change in ROS production was observed in CPF groups, the overall results confirmed the occurrence of oxidative stress through the alterations of GSH content, GPx, and SOD activity. Only intracellular GSH was evidently changed upon exposure to CPF and AFB₁ combined. Thus, this study suggested cellular GSH as a potential indicator for detecting the combined effects of CPF and AFB₁ in HepG2 cells, the detection of which could be adapted to estimate the potential toxicity of additional multiple toxicant exposures.

Neuroprotection by chotosan, a Kampo formula, against glutamate excitotoxicity involves the inhibition of GluN2B-, but not GluN2A-containing NMDA receptor-mediated responses in primary cultured cortical neurons

Chotosan (CTS), a traditional herbal formula called Kampo medicine, was shown to be effective in the treatment of vascular dementia in a clinical study, and exerted protective effects against transient cerebral ischemia-induced cognitive impairment in mice. In the present study, we investigated the neuroprotective effects of CTS using primary cultured rat cortical neurons. CTS (250-1000 μg/mL) inhibited neuronal death induced by 100 μM glutamate. This glutamate-induced neuronal death was blocked by a GluN2B-, but not GluN2A-containing NMDA receptor antagonist. Therefore, the neuroprotective effects of CTS were related to an inhibition of GluN2B-containing NMDA receptor-mediated responses.

Choto-san versus placebo for patients with dementia: systematic review and meta-analysis

BACKGROUND

Choto-san is a traditional medicine used for hypertension and headaches in Japan and China. Some studies have shown its effectiveness in the treatment of dementia. The present review aimed to assess the effectiveness and acceptability of Choto-san in the treatment of adults with cognitive impairment.

METHODS

We included randomized controlled trials comparing Choto-san with placebo for patients with dementia or mild cognitive impairment.

RESULTS

Three randomized controlled trials evaluating 219 participants were included. Two were studies on vascular dementia, and the other was on Alzheimer's dementia. There was no difference between Choto-san and placebo in terms of short-term dichotomous judgement of improvement, but Choto-san was more effective than placebo in terms of short-term improvement of cognitive function as measured by continuous outcomes. Also, dropouts judged it to be acceptable. However, the results were imprecise and/or heterogeneous. The number of participants included in the analysis was small (n = 199 in the primary analysis) and sometimes inconsistent, as indicated by the large I ² (72% in the primary analysis).

CONCLUSION

Low-quality evidence was suggestive of Choto-san's efficacy for vascular dementia, but the present results may be overestimated. Studies with a larger sample size and conducted over longer periods should be performed. Regardless, Choto-san can be one of the choices for the treatment of vascular dementia as it is well tolerated.

Chotosan (Diaoteng San)-induced improvement of cognitive deficits in senescence-accelerated mouse (SAMP8) involves the amelioration of angiogenic/neurotrophic factors and neuroplasticity systems in the brain

Background

Chotosan (CTS, Diaoteng San), a Kampo medicine (ie Chinese medicine) formula, is reportedly effective in the treatment of patients with cerebral ischemic insults. This study aims to evaluate the therapeutic potential of CTS in cognitive deficits and investigates the effects and molecular mechanism(s) of CTS on learning and memory deficits and emotional abnormality in an animal aging model, namely 20-week-old senescence-accelerated prone mice (SAMP8), with and without a transient ischemic insult (T2VO).

Methods

Age-matched senescence-resistant inbred strain mice (SAMR1) were used as control. SAMP8 received T2VO (T2VO-SAMP8) or sham operation (sham-SAMP8) at day 0. These SAMP8 groups were administered CTS (750 mg/kg, p.o.) or water daily for three weeks from day 3.

Results

Compared with the control group, both sham-SAMP8 and T2VO-SAMP8 groups exhibited cognitive deficits in the object discrimination and water maze tests and emotional abnormality in the elevated plus maze test. T2VO significantly exacerbated spatial cognitive deficits of SAMP8 elucidated by the water maze test. CTS administration ameliorated the cognitive deficits and emotional abnormality of sham- and T2VO-SAMP8 groups. Western blotting and immunohistochemical studies revealed a marked decrease in the levels of phosphorylated forms of neuroplasticity-related proteins, N-methyl-D-aspartate receptor 1 (NMDAR1), Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), cyclic AMP responsive element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in the frontal cortices of sham-SAMP8 and T2VO-SAMP8. Moreover, these animal groups showed significantly reduced levels of vasculogenesis/angiogenesis factors, vascular endothelial growth factor (VEGF), VEGF receptor type 2 (VEGFR2), platelet-derived growth factor-A (PDGF-A) and PDGF receptor α (PDGFRα). CTS treatment reversed the expression levels of these factors down-regulated in the brains of sham- and T2VO-SAMP8.

Conclusion

Recovery of impaired neuroplasticity system and VEGF/PDGF systems may play a role in the ameliorative effects of CTS on cognitive dysfunction caused by aging and ischemic insult.

Antioxidant and lipid peroxidation activities in rats fed with Aspergillus carbonarius carotenoid

Effect of feeding partially saturated canthaxanthin (PSC), purified from Aspergillus carbonarius mutant, was studied using four groups of female albino rats (n=6) for 4 weeks. While the control group received basal diet ad libitum, Groups I, II and III were fed with basal diet containing 50, 100 and 250 ppm PSC, respectively. PSC feeding did not cause any significant changes in food intake and there was no gain in body weight either. PSC included in the diet significantly decreased cholesterol in blood. There was 44.75% and 60.54% decrease in LDL-cholesterol in rats fed with 50 and 100 ppm carotenoid. Hepatic ascorbic acid content increased by 44.59% in rats fed with 50 ppm PSC. Dietary PSC at 250 ppm lowered lipid peroxides by 19.49%. Activities of antioxidant enzymes, glutathione transferase and catalase were significantly higher in serum and liver of PSC fed rats compared to the controls. The results suggested that PSC feeding can induce hypocholesterolmic and antioxidant properties in rats.

Biotransformed blueberry juice protects neurons from hydrogen peroxide-induced oxidative stress and mitogen-activated protein kinase pathway alterations

A growing body of evidence supports the therapeutic effects of blueberry in neurodegenerative disorders. Biotransformation of blueberry juice by Serratia vaccinii bacteria increases its phenolic content and antioxidant activity. In neuronal cell culture, biotransformed blueberry juice (BJ) significantly increased the activity of antioxidant enzymes, namely catalase and superoxide dismutase. Moreover, BJ protected neurons against H2O2-induced cell death in a dose-dependent manner. This associated with the upregulation of mitogen-activated protein kinase (MAPK) family enzymes p38 and c-Jun N-terminal kinase (JNK) activation, as well as with the protection of extracellular signal-regulated kinase (ERK1/2) and MAPK/ERK kinase (MEK1/2) activity loss induced by H2O2. The present studies demonstrate that BJ can protect neurons against oxidative stress possibly by increasing antioxidant enzyme activities and activating p38- and JNK-dependent survival pathways while blocking MEK1/2- and ERK1/2-mediated cell death. Thus, BJ may represent a novel approach to prevent and to treat neurodegenerative disorders, and it may represent a source of novel therapeutic agents against these diseases.

Uncaria rhynchophylla, a Chinese medicinal herb, has potent antiaggregation effects on Alzheimer's β-amyloid proteins

Because the deposition of beta-amyloid protein (Abeta) is a consistent pathological hallmark of Alzheimer's disease (AD) brains, inhibition of Abeta generation, prevention of Abeta fibril formation, or destabilization of preformed Abeta fibrils would be attractive therapeutic strategies for the treatment of AD. We examined the effects of several medicinal herbs used in traditional Chinese medical formulae on the formation and destabilization of Abeta fibrils by using the thioflavin T binding assay, atomic force microscopic imaging, and electrophoresis. Our study demonstrates that several of these herbs have potent inhibitory effects on fibril formation of both Abeta(1-40) and Abeta(1-42) in concentration-dependent manners; in particular, Uncaria rhynchophylla inhibited Abeta aggregation most intensively. Significant destabilization of preformed Abeta(1-40) and Abeta(1-42) fibrils was also induced by Uncaria rhynchophylla as well as some other herb extracts. Three-dimensional HPLC analysis indicated that the water extract of this herb contains several different chemical compounds, including oxindole and indol alkaloids, which have been regarded as neuroprotective. Our results suggest that Uncaria rhynchophylla has remarkably inhibitory effects on the regulation of Abeta fibrils, and we conclude that this medicinal herb could have the potency to be a novel therapeutic agent to prevent and/or cure AD.