Takahiro Shintani

Hydroxychavicol: a potent xanthine oxidase inhibitor obtained from the leaves of betel, Piper betle

The screening of Piperaceous plants for xanthine oxidase inhibitory activity revealed that the extract of the leaves of Piper betle possesses potent activity. Activity-guided purification led us to obtain hydroxychavicol as an active principle. Hydroxychavicol is a more potent xanthine oxidase inhibitor than allopurinol, which is clinically used for the treatment of hyperuricemia.

Extract prepared from the bark of Cinnamomum cassia Blume prevents glutamate-induced neuronal death in cultured cerebellar granule cells

We studied the protective effect of a water extract from the bark of Cinnamomum cassia Blume on glutamate‐induced neuronal death by MTT assay and its action on 45Ca2+ influx using cultured rat cerebellar granule cells. In a dose‐dependent manner, this extract (10−5–10−4 g/mL) significantly protected against glutamate‐induced cell death and also inhibited glutamate‐induced 45Ca2+ influx. These results suggest that the bark of Cinnamomum cassia has a protective effect on glutamate‐induced neuronal death through the inhibition of Ca2+ influx. Copyright

Effect of Uncariae ramulus et Uncus on endothelium in spontaneously hypertensive rats.

The protective effect of the extract of Uncariae ramulus et Uncus (URE) against endothelium disorder due to hypertension was investigated. We administered low (150 mg/kg/day) and high (450 mg/kg/day) doses of URE orally to spontaneously hypertensive rats for 8 weeks. Endothelium dependent vasodilatation by acetylcholine increased significantly in the high URE group compared with the control group. Endothelium dependent vasocontraction by xanthine oxidase decreased significantly in the high URE group compared with the control group. Serum NO2-/NO3- were tended to increase in the high URE group. It is suggested that URE may have a protective effect for the endothelium against the influence of hypertension.

Effect of kihito extract granules on cognitive function in patients with Alzheimer's-type dementia

Background:  It has been recently suggested that Japanese herbal (kampo) medicines, such as kami‐untan‐to, may improve cognitive function in elderly subjects with Alzheimers disease. Polygalae radix is thought to be a useful component of kami‐untan‐to because it enhances the activity of choline acetyltransferase in cultured neuronal cells. The purpose of the present study was to investigate the safety and usefulness of kihito extract granules, a commercially available Japanese herbal medicine that contains P. radix, for elderly patients with senile dementia.