Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Uncaria”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2004

Morphoanatomical studies of Uncaria tomentosa and Uncaria guianensis bark and leaves.

The genus Uncaria Schreber (Rubiaceae) includes species that are widely distributed in tropical areas. The inner bark of the stems and leaves of two native species of South America, Uncaria tomentosa (Willd. ex Roemer & Schultes) DC., and Uncaria guianensis (Aublet) J. F. Gmelin, "cat's claw" are used in either folk medicine or in procuring phytotherapeutic drugs. These species contain about sixty active substances which are being tested widely for possible medicinal value. The following applications are considered: peptic ulcer, rheumatism, tumours, antiinflammatory effect, inflammation, diabetes and as general tonic. Currently, Uncaria tomentosa is in demand as tea, tablets or capsules in more than 30 countries outside Perú, as well as inside the country. Pharmacognosy studies are required to determine the comparative morphoanatomical and micrographic features for identification and quality control purposes. Several microscopic parameters, including phloem fibers, calcium oxalate crystals, starch granules, trichomes, and foliar architecture should be considered. The aim of our work is to analyse comparative morphoanatomical and micrographic features which might provide assistance in the identification, analysis and standardization of Uncaria tomentosa (Willd. ex Roemer & Schultes) DC. and Uncaria guianensis (Aublet) J. F. Gmelin stem bark and leaves in order to obtain phytotherapeutic drugs, and of the crude drug as well.

Cat's Claw↗
PubMed2002

Anti-inflammatory and antioxidant activities of cat's claw (Uncaria tomentosa and Uncaria guianensis) are independent of their alkaloid content.

Cat's claw is an herbal medicine from the Amazon that is used widely to treat inflammatory disorders. The purpose of this study was to characterize the antioxidative and antiinflammatory properties of cat's claw, Uncaria tomentosa (UT) and Uncaria guianensis (UG). Alkaloids and flavanols were determined using reversed-phase HPLC; scavenging of 1,1-diphenyl-2-picrilhydrazyl (DPPH), hydroxyl radicals, and lipid peroxidation by spectrophotometry; and TNFalpha production by ELISA. Anti-inflammatory activity was assessed in vitro by inhibition of TNFalpha and nitrite production from RAW 264.7 cells exposed to LPS (50 ng/ml) and in vivo using the indomethacin-induced gastritis model. Apoptosis was assessed using the TUNEL technique and TNFalpha mRNA by in situ RT-PCR. In each of the antioxidant assays tested, UG was more potent than UT (P < 0.01). The total oxindole and pentacyclic alkaloid content of UT was 35-fold > UG. The IC50 value for inhibition of TNFalpha production was significantly (P < 0.01) higher for UT (14.1 ng/ml) vs UG (9.5 ng/ml), yet at concentrations that were considerable lower than that required for antioxidant activity. Non-alkaloid HPLC fractions from UT decreased LPS-induced TNFalpha and nitrite production in RAW 264.7 cells (P < 0.01) at a concentration range comparable to the parent botanical. Oral pretreatment for 3 d with UT protected against indomethacin-induced gastritis, and prevented TNFalpha mRNA expression and apoptosis. These results indicate that while both species of cat's claw provide effective antioxidant and anti-inflammatory activities, U. guianensis is more potent. In conclusion, the presence of oxindole or pentacyclic alkaloids did not influence the antioxidant and anti-inflammatory properties of cat's claw.

Alkaloids↗
PubMed2004

Effects of repeated administration of Uncaria hooks on the acquisition and central neuronal activities in ethanol-treated mice.

The effects of the repeated administration of Uncaria hooks were examined on the impaired memory acquisition and the level of neurotransmitters in the cortex, hippocampus and striatum in ethanol-treated mice, in comparison with those with L-deprenyl and N-methyl-D-glucamine as positive controls. Ethanol-induced amnesia was significantly ameliorated by repeated administration of methanol extract and alkaloid fraction of Uncaria hooks, similar to in the positive controls. Treatment with methanol extract and alkaloid fraction of Uncaria hooks significantly reduced the ethanol-induced increase of dopamine in the hippocampus. The 5-hydroxytryptamine and glutamic acid neuronal activities were significantly changed by Uncaria hooks, but not by L-deprenyl, in all examined brain tissues of ethanol-treated mice. On the other hand, the GABAergic and cholinergic neuronal activities did not show any significant changes by Uncaria hooks in any of the examined brain tissues of the ethanol-treated animals. The results suggest that the extracts of Uncaria hooks exert a beneficial effect on ethanol-induced memory impairment, and that the central 5-hydroxytryptaminergic and glutaminergic neuronal systems play an important role in the memory acquisition of Uncaria hooks.

Amnesia↗
PubMed2005

Uncaria rhynchophylla induces angiogenesis in vitro and in vivo.

Angiogenesis consists of the proliferation, migration, and differentiation of endothelial cells, and angiogenic factors and matrix protein interactions modulate this process. The aim of this study was to determine the angiogenic properties of Uncaria rhynchophylla. Uncaria rhynchophylla significantly enhanced human umbilical vein endothelial cells (HUVECs) proliferation in a dose-dependent manner. Neutralization of vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) by monoclonal antibody suppressed the Uncaria rhynchophylla stimulatory effect on proliferation. In addition, Uncaria rhynchophylla significantly increased chemotactic-migration on gelatin and tubular structures on Matrigel of HUVECs in a dose-dependent manner. Interestingly, Uncaria rhynchophylla dose-dependently increased VEGF, and bFGF gene expression and protein secretion of HUVEC. The angiogenic activity of Uncaria rhynchophylla was confirmed using an in vivo Matrigel angiogenesis model, showing promotion of blood vessel formation. These results suggest that Uncaria rhynchophylla could potentially used to accelerate vascular wound healing or to promote the growth of collateral blood vessel in ischemic tissues.

Angiogenesis Inducing Agents↗
PubMed2006

Treatment of THP-1 cells with Uncaria tomentosa extracts differentially regulates the expression if IL-1beta and TNF-alpha.

Uncaria tomentosa, commonly known as cat's claw, is a medicinal plant native to Peru, which has been used for decades in the treatment of various inflammatory disorders. Uncaria tomentosa can be used as an antioxidant, has anti-apoptotic properties, and can enhance DNA repair, however it is best know for its anti-inflammatory properties. Treatment with Uncaria tomentosa extracts inhibits the production of the pro-inflammatory cytokine, TNF-alpha, which is a critical mediator of the immune response. In this paper, we showed that treatment of THP-1 monocyte-like cells with Uncaria tomentosa extracts inhibited the MAP kinase signaling pathway and altered cytokine expression. Using ELISA assays, we showed that treatment with Uncaria tomentosa extracts augmented LPS-dependent expression of IL-1beta by 2.4-fold, while inhibiting the LPS-dependent expression of TNF-alpha by 5.5-fold. We also showed that treatment of LPS-stimulated THP-1 cells with Uncaria tomentosa extracts blocked ERK1/2 and MEK1/2 phosphorylation in a dose-dependent manner. These data demonstrate that treatment of THP-1 cells with Uncaria tomentosa extracts has opposite effects on IL-1beta and TNF-alpha secretion, and that these changes may involve effects on the MAP kinase pathway.

Cat's Claw↗
PubMed2003

Protective effect of methanol extract of Uncaria rhynchophylla against excitotoxicity induced by N-methyl-D-aspartate in rat hippocampus.

Uncaria rhynchophylla is a medicinal herb used for convulsive disorders in Oriental medicine. In this study, the effect of the methanol extract of Uncaria rhynchophylla against N-methyl-D-aspartate (NMDA)-induced excitotoxicity was investigated. Pretreatment with the extract of Uncaria rhynchopylla reduced the degree of neuronal damage induced by NMDA exposure in cultured hippocampal slices. In the patch clamp study, Uncaria rhynchophylla significantly inhibited NMDA receptor-activated ion current in acutely dissociated hippocampal CA1 neurons. These results indicate that Uncaria rhynchophylla offers protection against NMDA-induced neuronal injury and inhibitory action on NMDA receptor-mediated ion current may be a mechanism behind the neuroprotective effect of Uncaria rhynchophylla.

Animals↗
PubMed2004

Cytoprotective effect on oxidative stress and inhibitory effect on cellular aging of Uncaria sinensis Havil.

The ethanol extract from the hooks and stems of Uncaria sinensis Havil (Rubiaceae) exhibited significant inhibitory activity on oxidative stress and the age-dependent shortening of the telomeric DNA length. In the peroxidation model using t-BuOOH, the Uncaria sinensis extract showed a notable cytoprotective effect on the HEK-N/F cells with 65.0 +/- 3.0% of cell viability when compared with control cells at a concentration of 50 microg/ml. In addition, the Uncaria sinensis extract exhibited a significant cytoprotective effect against UVB-induced oxidative damage. The life-span of the HEK-N/F cells was elongated by 201% as a result of the continuous administration of 3 microg/ml of the Uncaria sinensis extract compared to that of the control. These observations were attributed to the inhibitory effect of the Uncaria sinensis extract on the age-dependent shortening of the telomere length as shown by the Southern blots of the terminal restriction fragments (TRFs) of DNA extracted from subculture passages.

Cell Line↗
PubMed2006

Anxiolytic effects of the aqueous extract of Uncaria rhynchophylla.

The purpose of this study was to characterize the putative anxiolytic-like effects of the aqueous extract of hooks with stem of Uncaria rhynchophylla using the elevated plus maze (EPM) and the hole-board apparatus in rats and mice. Control rats were treated with an equal volume of saline, and positive control rats with buspirone (1 mg/kg). Single or repeated treatments of the aqueous extract of Uncaria rhynchophylla (200 mg/kg/day, p.o.) for 7 days significantly increased the time-spent and entries into open arms of the EPM, and reduced the time-spent and entries into the closed arms versus saline controls (P<0.05). However, no changes in spontaneous locomotor activity or myorelaxant effects were observed versus saline controls. In the hole-board test, repeated treatment with the aqueous extract of Uncaria rhynchophylla (100 or 200 mg/kg/day, p.o.) significantly increased the number of head-dips (P<0.05). In addition, the anxiolytic-like effects of Uncaria rhynchophylla extract as assessed using the EPM test were abolished by WAY 100635 (0.3 mg/kg, i.p.), a 5-HT(1A) receptor antagonist. These results suggest that Uncaria rhynchophylla is an effective anxiolytic agent, and acts via the serotonergic nervous system.

Administration, Oral↗
PubMed2004

In vitro effects of two extracts and two pure alkaloid preparations of Uncaria tomentosa on peripheral blood mononuclear cells.

In the traditional Peruvian medicine, hot aqueous extracts of Uncaria tomentosa have been used for the treatment of a wide range of health problems, particularly digestive complaints and arthritis. Some of the beneficial effects observed in patients suggest an immunomodulatory capacity of Uncaria tomentosa extracts. In this study, the effects of two extracts and two mixtures of tetracyclic and pentacyclic oxindole alkaloids of Uncaria tomentosa were investigated in freshly isolated human peripheral blood mononuclear cells (PBMC) stimulated with the mitogens phytohaemagglutinin (PHA) and concanavalin A (Con A) in vitro. Neopterin production and tryptophan degradation were monitored in culture supernatants to determine the effects of the test substances on immunobiochemical pathways induced by interferon-gamma. Compared to unstimulated cells PHA and Con A increased the production of neopterin and degradation of tryptophan (p < 0.01). HCl and ethanol extracts and mixtures of alkaloids of Uncaria tomentosa inhibited both effects in a dose-dependent manner, the lowest effective concentrations of the extracts were 500 - 1000 microg/mL and of the alkaloid mixtures 100 - 175 microg/mL (p < 0.05 and < 0.01). With the highest concentrations of extracts and mixtures complete suppression of mitogen-induced neopterin production and tryptophan degradation was observed. These data demonstrate that Uncaria tomentosa extracts and mixtures of alkaloids modulate the immunobiochemical pathways induced by interferon-gamma. The findings imply a potential application of the extracts as immunoregulators and would be in line with observations in patients using these extracts.

Adjuvants, Immunologic↗
PubMed1999

Evaluation of the protective effects of alkaloids isolated from the hooks and stems of Uncaria sinensis on glutamate-induced neuronal death in cultured cerebellar granule cells from rats.

We have previously shown that an aqueous extract of the hooks and stems of Uncaria sinensis (Oliv.) Havil., Uncariae Uncus Cum Ramulusis, protects against glutamate-induced neuronal death in cultured cerebellar granule cells by inhibition of Ca2+ influx. Because it is not known which components of Uncaria sinensis are active, in this study we have evaluated, by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) staining, the neuroprotective effects of the oxyindole alkaloids corynoxeine, rhynchophylline, isorhynchophylline and isocorynoxeine, and the indole alkaloids geissoschizine methyl ether, hirsuteine and hirsutine, isolated from the hooks and stems of Uncaria sinensis, on glutamate-induced cell death. We also investigated the inhibitory effects of the compounds on 45Ca2+ influx in cultured rat cerebellar granule cells. Cell viability evaluated by the MTT assay was significantly increased by application of rhynchophylline (10(-3) M), isorhynchophylline (10(-4)-10(-3) M), isocorynoxeine (10(-4)-10(-3) M), hirsuteine (10(-4)-3 x 10(-4) M) or hirsutine (10(-4)-3 x 10(-4) M) compared with exposure to glutamate only, with the effect of isorhynchophylline being the strongest. The increased 45Ca2+ influx into cells induced by glutamate was significantly inhibited by administration of rhynchophylline (10(-3) M), isorhynchophylline (3 x 10(-4)-10(-3) M), isocorynoxeine (3 x 10(-4)-10(-3) M), geissoschizine methyl ether (10(-3) M), hirsuteine (3 x 10(-4)-10(-3) M) or hirsutine (3 x 10(-4)-10(-3) M). These results suggest that oxyindole alkaloids such as isorhynchophylline, isocorynoxeine and rhynchophylline and indole alkaloids such as hirsuteine and hirsutine are the active components of the hooks and stems of Uncaria sinensis which protect against glutamate-induced neuronal death in cultured cerebellar granule cells by inhibition of Ca2+ influx.

Alkaloids↗
PubMed2005

Monoamine oxidase B (MAO-B) inhibition by active principles from Uncaria rhynchophylla.

Attenuation of monoamine oxidase B (MAO-B) activity may provide protection against oxidative neurodegeneration. For this reason, inhibition of MAO-B activity is used as part of the treatment of Parkinson's and Alzheimer's patients. The hook of Uncaria rhynchophylla (Miq.) Jacks. (Rubiaceae) is a traditional Chinese herbal drug that is generally used to treat convulsive disorders. In this study, the fractionation and purification of Uncaria rhynchophylla extracts using a bioguided assay isolated two known compounds, (+)-catechin and (-)-epicatechin. The compounds inhibited MAO-B, as measured by an assay of rat brain MAO-B separated by electrophoresis on a 7.5% native polyacrylamide gel. The IC(50) values of (+)-catechin and (-)-epicatechin were 88.6 and 58.9 microM, respectively, and inhibition occurred in a dose-dependent manner, as measured by the fluorescence method. The Lineweaver-Burk plot revealed K(i) values for (+)-catechin and (-)-epicatechin of 74 and 21 microM, respectively. This suggests that these two compounds, isolated here for the first time from Uncaria rhynchophylla, might be able to protect against neurodegeneration in vitro, and, therefore, the molecular mechanism deserves further study. This finding may also increase interest in the health benefits of Uncaria rhynchophylla.

Animals↗
PubMed2005

Ethnobotany, phytochemistry and pharmacology of Uncaria (Rubiaceae).

The Uncaria genus is an important source of medicinal natural products, particularly alkaloids and triterpenes. The collected information is an attempt to cover the more recent developments in the ethnobotany, pharmacology and phytochemistry of this genus. During the past 20 years, alkaloids, terpenes, quinovic acid glycosides, flavonoids and coumarins have been isolated from Uncaria. Fifty-three novel structures are reported in this review. The species in which the largest number of compounds has been identified is the Peruvian Uncaria tomentosa or 'cat's claw.' Pharmacological studies are described according to cytotoxicity, anti-inflammatory, antiviral, immunostimulation, antioxidant, CNS-related response, vascular, hypotensive, mutagenicity and antibacterial properties. The potential for development of leads from Uncaria continues to grow, particularly in the area of immunomodulatory, anti-inflammatory and vascular-related conditions. The information summarized here is intended to serve as a reference tool to practitioners in the fields of ethnopharmacology and natural products chemistry.

Adjuvants, Immunologic↗
PubMedDate not supplied

Induction of apoptosis and inhibition of proliferation in human tumor cells treated with extracts of Uncaria tomentosa.

Growth inhibitory activities of novel water extracts of Uncaria tomentosa (C-Med-100) were examined in vitro using two human leukemic cell lines (K562 and HL60) and one human EBV-transformed B lymphoma cell line (Raji). The proliferative capacities of HL60 and Raji cells were strongly suppressed in the presence of the C-Med-100 while K562 was more resistant to the inhibition. Furthermore, the antiproliferative effect was confirmed using the clonogenic assay, which showed a very close correlation between C-Med-100 concentration and the surviving fraction. The suppressive effect of Uncaria tomentosa extracts on tumor cell growth appears to be mediated through induction of apoptosis which was demonstrated by characteristic morphological changes, internucleosomal DNA fragmentation after agarose gel electrophoresis and DNA fragmentation quantification. C-Med-100 induced a delayed type of apoptosis becoming most dose-dependently prominent after 48 hours of exposure. Both DNA single and double strand breaks were increased 24 hours after C-Med-100 treatment, which suggested a well-established linkage between the DNA damage and apoptosis. The induction of DNA strand breaks coupled to apoptosis may explain the growth inhibition of the tumor cells by Uncaria tomentosa extracts. These results provide the first direct evidence for the antitumor properties of Uncaria tomentosa extracts to be via a mechanism of selective induction of apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed2006

Uncaria rhynchophylla, a Chinese medicinal herb, has potent antiaggregation effects on Alzheimer's beta-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.

Alzheimer Disease↗
PubMed2004

Advances in chemistry and bioactivity of the genus Uncaria.

The alkaloids of the pantropical genus Uncaria (Rubiaceae) were reviewed extensively by Phillipson et al. in (1978) Since then a host of papers with new results has been published. The compounds discovered are from three major groups: (1) alkaloids; (2) terpenoids; and (3) flavonoids. Some highly unusual structures have been reported. Although there are at least 35 species of Uncaria known, recent research focussed on a relatively small number of species. During recent years bioactivity of extracts and pure compounds isolated from Uncaria species have been increasingly investigated. These include anticonvulsive, antiinflammatory, antimutagenic, antioxidant, cytoprotective, hypotensive, and immunoregulatory effects. The literature since 1978 is reviewed and 133 references are given.

Alkaloids↗
PubMed1999

[Survey on traditional medicinal resources of Uncaria distributed in China].

OBJECTIVE: To make clear the botanical origin of medicinal Uncaria distributed in China and the situation of its use in folk medicines. METHODS: Collecting data and making on-the-spot investigation. RESULTS: There are thirteen medicinal plants which belong to Uncaria genus, and ten of them are commercially available. A clear idea was obtained of their geographical distribution, distribution features and practical experiences in folk application. CONCLUSION: This investigation is helpful in further researching and exploring the resources of Uncaria for medical use, as well as provides a scientific basis for production, management and safe use of crude drugs.

China↗
PubMed2000

Vasodilator effect of extract prepared from Uncariae ramulus on isolated rat aorta.

Uncariae ramulus et Uncus (URE) has a vasodilator effect. Its mechanism consists of not only endothelium-independent relaxation with Ca2+ channel blocking effect but also endothelium-dependent relaxation with nitric oxide. The active components are alkaloids and tannin contained in Uncariae ramulus et Uncus. They also show a superoxide dismutase-like effect and suppressed vasocontraction induced by xanthine and xanthine oxidase. These mechanisms may also influence vasodilatation by Uncariae ramulus et Uncus in vivo.

Analysis of Variance↗
PubMed2000

Effects of Uncaria tomentosa total alkaloid and its components on experimental amnesia in mice: elucidation using the passive avoidance test.

The effects of Uncaria tomentosa total alkaloid and its oxindole alkaloid components, uncarine E, uncarine C, mitraphylline, rhynchophylline and isorhynchophylline, on the impairment of retention performance caused by amnesic drugs were investigated using a step-down-type passive avoidance test in mice. In this test, the retention performance of animals treated with the amnesic and test drugs before training was assessed 24 h after training. Uncaria tomentosa total alkaloid (10-20 mg kg(-1), i.p.) and the alkaloid components (10-40 mg kg(-1), i.p.), as well as the muscarinic receptor agonist oxotremorine (0.01 mg kg(-1), i.p.), significantly attenuated the deficit in retention performance induced by the muscarinic receptor antagonist scopolamine (3 mg kg(-1), i.p.). The effective doses of uncarine C and mitraphylline were larger than those of other alkaloid components. Uncarine E (20 mg kg(-1), i.p.) also blocked the impairment of passive avoidance performance caused by the nicotinic receptor antagonist mecamylamine (15 mg kg(-1), i.p.) and the N-methyl-D-aspartate (NMDA) receptor antagonist (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP; 7.5 mg kg(-1), i.p.), but it failed to affect the deficit caused by the benzodiazepine receptor agonist diazepam (2 mg kg(-1), i.p.). Rhynchophylline significantly reduced the mecamylamine-induced deficit in passive avoidance behaviour, but it failed to attenuate the effects of CPP and diazepam. These results suggest that Uncaria tomentosa total alkaloids exert a beneficial effect on memory impairment induced by the dysfunction of cholinergic systems in the brain and that the effect of the total alkaloids is partly attributed to the oxindole alkaloids tested. Moreover, these findings raised the possibility that the glutamatergic systems are implicated in the anti-amnesic effect of uncarine E.

Alkaloids↗