Hydroxyobtustyrene protects neuronal cells from chemical hypoxia-induced cell death.

Hydroxyobtustyrene is a derivative of cinnamyl phenol isolated from Dalbergia odorifera T. Chen. The heartwood, known as 'JiangXiang', is a traditional Chinese medicine. Previous studies showed that hydroxyobtustyrene inhibited the biosynthesis of prostaglandins, which are mediators of neuronal cell death in ischemia. However, it currently remains unclear whether hydroxyobtustyrene protects neurons against ischemic stress. In the present study, we investigated the protective effects of hydroxyobtustyrene against sodium cyanide (NaCN)-induced chemical ischemia. Hippocampal neurons were cultured from the cerebral cortices of E18 Wistar rats. The effects of hydroxyobtustyrene on neuronal survival and trophic effects were estimated under lower and higher cell density conditions. After the treatment of 1 mM NaCN with or without hydroxyobtustyrene, an MTT assay, Hoechst staining, and immunocytochemistry for cyclooxygenase (COX)-2 were performed. Hydroxyobtustyrene increased cell viability under lower, but not normal density conditions. Neither the neurite number nor the length was influenced by hydroxyobtustyrene. NaCN significantly decreased viability and increased fragmentation in cell nuclei, and these changes were prevented by hydroxyobtustyrene. Moreover, NaCN increased the number of COX-2-positive neurons, and this was significantly prevented by the co-treatment with hydroxyobtustyrene. Therefore, hydroxyobtustyrene protected cultured hippocampal neurons against NaCN-induced chemical ischemia, which may be mediated by the inhibition of COX-2 production.

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.

Serotonergic and dopaminergic systems are implicated in antidepressant-like effects of chotosan, a Kampo formula, in mice.

We previously demonstrated that chotosan (CTS), a traditional herbal formula called Kampo medicine, improves diabetes-induced cognitive deficits. In the present study, we investigated the antidepressant-like effects of CTS in mice. The administration of CTS (1.0 g/kg, for 3 days) decreased the immobility time in the forced-swim test, and this decrease was prevented by the prior administration of sulpiride (an antagonist of D2/3 receptors) and WAY100635 (an antagonist of 5-HT1A receptors). None of the treatments tested altered the locomotor activity of mice. These results suggest that CTS exerts antidepressant-like effects through changes in the serotonergic and dopaminergic systems.

Chemical profiling with HPLC-FTMS of exogenous and endogenous chemicals susceptible to the administration of chotosan in an animal model of type 2 diabetes-induced dementia.

In our previous study, the daily administration of chotosan (CTS), a Kampo formula consisting of Uncaria and other 10 different crude drugs, ameliorated cognitive deficits in several animal models of dementia including type 2 diabetic db/db mice in a similar manner to tacrine, an acetylcholinesterase inhibitor. The present study investigated the metabonomics of CTS in db/db mice, a type 2 diabetes model, and m/m mice, a non-diabetes control strain, to identify the exogenous and endogenous chemicals susceptible to the administration of CTS using high performance liquid chromatography equipped with an orbitrap hybrid Fourier transform mass spectrometer. The results obtained revealed that the systemic administration of CTS for 20 days led to the distribution of Uncalia plant-derived alkaloids such as rhynchophylline, hirsuteine, and corynoxeine in the plasma and brains of db/db and m/m mice and induced alterations in four major metabolic pathways; i.e., (1) purine, (2) tryptophan, (3) cysteine and methionine, (4) glycerophospholipids in db/db mice. Moreover, glycerophosphocholine (GPC) levels in the plasma and brain were significantly higher in CTS-treated db/db mice than in vehicle-treated control animals. The results of the in vitro experiment using organotypic hippocampal slice cultures demonstrated that GPC (10-30 µM), as well as tacrine, protected hippocampal cells from N-methyl-d-aspartate-induced excitotoxicity in a manner that was reversible with the muscarinic receptor antagonist scopolamine, whereas GPC had no effect on the activity of acetylcholinesterase in vitro. Our results demonstrated that some CTS constituents with neuropharmacological activity were distributed in the plasma and brain tissue following the systemic administration of CTS and may subsequently have affected some metabolic pathways including glycerophospholipid metabolism and cognitive function in db/db mice. Moreover, the present metabonomic analysis suggested that GPC is a putative endogenous chemical that may be involved in the tacrine-like actions of CTS in the present diabetic animal model.

Kampo formulations, chotosan, and yokukansan, for dementia therapy: existing clinical and preclinical evidence.

Cognitive deficits and behavioral and psychological symptoms of dementia (BPSD) are typical features of patients with dementia such as Alzheimer's disease (AD), vascular dementia (VD), and other forms of senile dementia. Clinical evidence has demonstrated the potential usefulness of chotosan (CTS) and yokukansan (YKS), traditional herbal formulations called Kampo medicines, in the treatment of cognitive disturbance and BPSD in dementia patients, although the indications targeted by CTS and YKS in Kampo medicine differ. The availability of CTS and YKS for treating dementia patients is supported by preclinical studies using animal models of dementia that include cognitive/emotional deficits caused by aging and diabetes, dementia risk factors. These studies have led not only to the concept of a neuronal basis for the CTS- and YKS-induced amelioration of cognitive function and emotional/psychiatric symptom-related behavior in animal models, but also to a proposal that ingredient(s) of Uncariae Uncis cum Ramulus, a medicinal herb included in CTS and YKS, may play an important role in the actions of these formulae in dementia patients. Further studies are needed to clarify the active ingredients of these formulae and their target endogenous molecules implicated in the anti-dementia drug-like actions.

Docosahexaenoic acid provides protection from impairment of learning ability in Alzheimer's disease model rats.

Docosahexaenoic acid (C22:6, n-3), a major n-3 fatty acid of the brain, has been implicated in restoration and enhancement of memory-related functions. Because Alzheimer's disease impairs memory, and infusion of amyloid-beta (Abeta) peptide (1-40) into the rat cerebral ventricle reduces learning ability, we investigated the effect of dietary pre-administration of docosahexaenoic acid on avoidance learning ability in Abeta peptide-produced Alzheimer's disease model rats. After a mini-osmotic pump filled with Abeta peptide or vehicle was implanted in docosahexaenoic acid-fed and control rats, they were subjected to an active avoidance task in a shuttle avoidance system apparatus. Pre-administration of docosahexaenoic acid had a profoundly beneficial effect on the decline in avoidance learning ability in the Alzheimer's disease model rats, associated with an increase in the cortico-hippocampal docosahexaenoic acid/arachidonic acid molar ratio, and a decrease in neuronal apoptotic products. Docosahexaenoic acid pre-administration furthermore increased cortico-hippocampal reduced glutathione levels and glutathione reductase activity, and suppressed the increase in lipid peroxide and reactive oxygen species levels in the cerebral cortex and hippocampus of the Alzheimer's disease model rats, suggesting an increase in antioxidative defence. Docosahexaenoic acid is thus a possible prophylactic means for preventing the learning deficiencies of Alzheimer's disease.