Uncariae Ramulus Research Articles

Neuroprotective Effect of Some Plant Extracts in Cultured CT105-Induced PC12 Cells

Carboxyl-terminal fragments of APP (CT) have been found in plaques, microvessels and the neurofibrillary tangles in the brains of AD patients. These carboxyl-terminal fragments, which contain the complete Abeta sequence, appear to be toxic to neurons in culture cells. However, the possible role of other cleaved products of APP is less clear. We showed that a recombinant carboxy-terminal 105 amino acid fragment (CT105) of APP induced strong neurotoxicity in PC12 cells. We prepared alcoholic extract from Oriental herbal plants and screened their protective effects against CT105-induced cell death in PC12 cells after the treatment of these extracts. Of the 10 kinds of plant extracts, 12 kinds of extracts had considerable protective effects against CT105-induced cell death, especially, Uncariae Ramulus et Uncus (UREU), Gastrodia elata (GAE), Evodia officinalis (EO) and Panax ginseng (PAG) showed the most protective effect at the concentration of 50 microg/ml. BuOH extract of UREU and GAE possessed the strongest protective effects against neurotoxicity of CT105-induced PC12 cells and showed inhibitory effect with IC50 values of 4.8 and 8.3 microg/ml, respectively. These plants are promising candidates of neuroprotective effects and would be useful for the treatment of the neuronal degenerative diseases such as Alzheimer's diseases.

Effects of Methanol Extract of Uncariae Ramulus et Uncus on Ibotenic Acid-Induced Amnesia in the Rat

In the present study, we investigated the effects of Uncariae Ramulus et Uncus (UR) on learning and memory in the Morris water maze task and the central cholinergic system of rats with excitotoxic medial septum (MS) lesion. In the water maze test, the animals were trained to find a platform in a fixed position during 6 days and then received a 60-s probe trial in which the platform was removed from the pool on the 7th day. Ibotenic lesion of the MS showed impaired performance of the maze test and severe cell losses in the septohippocampal cholinergic system (SHC), as indicated by decreased choline acetyltransferase-immunoreactivity and acetylcholinesterase-reactivity in the hippocampus. Daily administrations of UR (100 mg/kg, i.p.) for 21 consecutive days produced significant reversals of ibotenic acid-induced deficit in learning and memory. These treatments also reduced the loss of cholinergic immunoreactivity in the hippocampus induced by ibotenic acid. These results demonstrated that impairments of spatial learning and memory may be attributable to degeneration of SHC neurons and that UR ameliorated learning and memory deficits partly through neuroprotective effects on the central acetylcholine system. Our studies suggest that UR may be useful in the treatment of Alzheimer’s disease.

Protective effects of methanol extract of Acori graminei rhizoma and Uncariae Ramulus et Uncus on ischemia-induced neuronal death and cognitive impairments in the rat

Acori graminei rhizoma (AGR) and Uncariae Ramulus et Uncus (URE) have been widely used as herbal medicine against ischemia. In order to investigate whether AGR and URE influenced cerebral ischemia-induced neuronal and cognitive impairments, we examined the effect of AGR and URE on ischemia-induced cell death in the striatum, cortex and hippocampus, and on the impaired learning and memory in the Morris water maze and radial eight-arm maze in rats. After middle cerebral artery occlusion (MCAO) for 2 h, rats were administered saline, AGR or URE (100 mg/kg, p.o.) daily for three weeks, followed by their training to the tasks. In the water maze test, the animals were trained to find a platform in a fixed position during 6 days and then received a 60-s probe trial in which the platform was removed from the pool on the 7th day. In the radial eight-arm maze, animals were tested six times per week for 1 week. Rats with ischemic insults showed impaired learning and memory on the tasks. Pretreatment with AGR and URE produced a significant improvement in escape latency to find the platform in the Morris water maze and in the number of choice errors in the radial arm maze test. Consistent with behavioral data, pretreatments with AGR and URE significantly reduced ischemia-induced cell death in the hippocampal CA1 area. These results demonstrated that AGR and URE have a protective effect against ischemia-induced neuronal loss and learning and memory damage. Our studies suggest that AGR and URE may be useful in the treatment of vascular dementia.

Geissoschizine methyl ether, an indole alkaloid extracted from Uncariae Ramulus et Uncus, is a potent vasorelaxant of isolated rat aorta

Effects of geissoschizine methyl ether, an indole alkaloid isolated from the hook of Uncariae Ramulus et Uncus, on vascular responses were examined using isolated strips of rat aorta. Geissoschizine methyl ether (10 −7–10 −4 M) relaxed norepinephrine (5×10 −8 M)-induced contraction in a dose-dependent manner. The potency (50% efficacy concentration, EC 50=0.744 μM) was approximately 14 times greater than that (EC 50=10.6 μM) of hirsutine, one of the indole alkaloids isolated from Uncariae Ramulus et Uncus that demonstrates a vasorelaxant effect by Ca 2+-channel blocking. The vasorelaxant effect of geissoschizine methyl ether found at the lower concentrations (10 −7–3×10 −6 M) on the norepinephrine-induced contraction was abolished by pretreatment with N G-nitro- l-arginine (10 −4 M), an inhibitor of nitric oxide synthesis, or by denuding aortas of endothelium, while the effects at the higher concentrations (10 −5–10 −4 M) were not completely prevented by either N G-nitro- l-arginine and deendothelialization. Furthermore, geissoschizine methyl ether did not relax high K +-, Ca 2+- and a Ca 2+-channel agonist Bay K8644-induced contractions at the lower concentrations that markedly relaxed the norepinephrine-induced contractions, while the higher concentrations of geissoschizine methyl ether relaxed the high K +-, Ca 2+- and Bay K8644-induced contractions. These results suggest that the vasorelaxant effect of geissoschizine methyl ether is composed of two different mechanisms: endothelial dependency with nitric oxide and endothelial independency with voltage-dependent Ca 2+-channel blocking.

Effect of Choto-san, a Kampo medicine, on the cerebral blood flow autoregulation in spontaneously hypertensive rats.

To clarify the mechanism of the benefical effect of Choto-san on cerebral circulation in hypertensive patients, the influence of Choto-san on cerebral blood flow (CBF) during hemorrhagic hypotension was evaluated in 10- to 11-month-old spontaneously hypertensive rats. The lower limit of CBF autoregulation, defined as the mean arterial blood pressure at which CBF decreased by 10% of the baseline value, was dose-dependently lowered when Choto-san (0.5 - 2.0 g/kg per day, p.o.) was administered for 14 consecutive days. Uncariae Ramulus et Uncus (150 mg/kg per day, p.o.), one of the crude drug components of Choto-san, showed an effect equivalent to that of Choto-san. The action of Choto-san (2.0 g/kg per day, p.o.) or Uncariae Ramulus et Uncus on the autoregulatory response of cerebral vessels was eliminated by treatment with N(G)-nitro-L-arginine methyl ester (10 mg/kg, i.v.), an inhibitor of nitric oxide synthase. These results suggested that the activation of nitric oxide synthase by Uncariae Ramulus et Uncus contributed to at least part of the improvement in the cerebral circulation caused by Choto-san.

Effect of Choto-san, a Kampo Medicine, on the Cerebral Blood Flow Autoregulation in Spontaneously Hypertensive Rats

To clarify the mechanism of the beneficai effect of Choto-san on cerebral circulation in hypertensive patients, the influence of Choto-san on cerebral blood flow (CBF) during hemorrhagic hypotension was evaluated in 10- to 11-month-old spontaneously hypertensive rats. The lower limit of CBF autoregulation, defined as the mean arterial blood pressure at which CBF decreased by 10% of the baseline value, was dose-dependently lowered when Choto-san (0.5-2.0 g/kg per day, p.o.) was administered for 14 consecutive days. Uncariae Ramulus et Uncus (150mg/kg per day, p.o.), one of the crude drug components of Choto-san, showed an effect equivalent to that of Choto-san. The action of Choto-san (2.0 g/kg per day, p.o.) or Uncariae Ramulus et Uncus on the autoregulatory response of cerebral vessels was eliminated by treatment with NG-nitro-l-arginine methyl ester (10 mg/kg, i.v.), an inhibitor of nitric oxide synthase. These results suggested that the activation of nitric oxide synthase by Uncariae Ramulus et Uncus contributed to at least part of the improvement in the cerebral circulation caused by Choto-san.

S-10-3 - Effects of alkaloids contained in Uncariae ramulus et uncus on circulatory systems: special reference to their activities on cellular calcium regulations in vessels

S-10-3 - Effects of alkaloids contained in Uncariae ramulus et uncus on circulatory systems: special reference to their activities on cellular calcium regulations in vessels

Screening test for calcium antagonist in natural products. The active principles of Uncariae ramulus et uncus

We have previously reported on the Ca2+-blocking activity and active constituents of natural products. In the course of screening, Uncariae ramulus et uncus, a chinese herbal medicine, was found to possess such activity. In this paper, we attempted to characterize its active constituent which plays an important role in Ca2+-blocking activity. Its active principles were identified to be oxyindole-type alkaloids, rhynchophylline, corynoxeine, isorhynchophylline and isocorynoxeine, that showed inhibitory effects, similar to that of verapamil, on contractile response to high concentration of potassium ion (rats), CaCl2 (rats), norepinephrine in normal and Ca2+-free medium (rats and rabbits) and 45Ca2+-uptake (rats) in thoracic aorta with an activity two orders of magnitude less than the activity of verapamil.

Determination of berberine-type alkaloids in Coptidis Rhizoma, Phellodendri Cortex and their oriental pharmaceutical preparations by ion pair high performance liquid chromatography.

Berberine, palmatine and coptisine in Coptidis Rhizoma, Phellodendri Cortex and their oriental pharmaceutical preparations were determined by ion pair high performance liquid chromatography. Coptidis Rhizoma obtained in China had two unknown peaks which were not detected in that of Japan, and the ratios of palmatine to berberine in Chinese sample were ranged from 9.1 to 41.5%, meanwhile those in Japanese sample were from 1.4 to 4.8%. Discrimination between Chinese sample and Japanese one is possible from the ratio of these alkaloids. On the other hand, regarding Phellodendri Cortex constitutive difference between Chinese sample and Japanese one was not obtained. The recoveries of the alkaloids in the decoction of oriental pharmaceutical preparation were lower by 5093% than that of the powders, and those in even shichimotsukoka-to which did not contain Glycyrrhizae Radix and Rhei Rhizoma were decreased in its decoction was lower by about 50% than the powder. It was suggested that there were any components in Paeoniae Radix, Cnidii Rhizoma and Uncariae Ramulus which interacted with berberine-type alkaloids.

Studies on the Decocting of Uncariae Ramulus et Uncus

The decocted extract of Uncariae Ramulus et Uncus, for which prolonged boiling is presumed to reduce its activities, was extracted with n-hexane-chloroform (5: 1) and methanol consecutively. The patterns of each organic solvent extract were analysed with thinlayer chromatography (TLC) by several solvent systems using the Dual-wavelength TLC Scanner. No clear difference in the patterns was evident in any of the 10-120 min decocted extracts.The comparison of patterns of the chromatograms however revealed some new informations.