Antioxidant activity of ethanolic and aqueous extracts of Uncaria tomentosa (Willd.) DC

Phlomis crinita Cav. From Algeria: A source of bioactive compounds possessing antioxidant and wound healing activities

ETHNOPHARMACOLOGICAL RELEVANCE

Phlomis crinita Cav. (Lamiaceae), locally known as "El Khayata" or "Kayat El Adjarah", is traditionally used in Algeria for its wound-healing properties.

AIM OF THE STUDY

Investigate, for the first time, the phytochemical profile, safety, antioxidant and wound-healing activities of the flowering tops methanolic extract of P. crinita (PCME) collected from Bouira Province in the North of Algeria.

MATERIALS AND METHODS

Preliminary phytochemical assays were carried out on PCME to quantify the main classes of bioactive compounds, such as total phenols, flavonoids, and tannins. An in-depth LC-DAD-ESI-MS analysis was carried out to elucidate the phytochemical profile of this plant species. Antioxidant activity was investigated by several colorimetric and fluorimetric assays (DPPH, TEAC, FRAP, ORAC, β-carotene bleaching and ferrozine assay). The acute oral toxicity of PCME (2000 mg/kg b.w.) was tested in vivo on Swiss albino mice, whereas the acute dermal toxicity and wound-healing properties of the PCME ointment (1-5% PCMO) were tested in vivo on Wistar albino rats. Biochemical and histological analyses were carried out on biological samples.

RESULTS

The phytochemical screening highlighted a high content of phenolic compounds (175.49 ± 0.8 mg of gallic acid equivalents/g of dry extract), mainly flavonoids (82.28 ± 0.44 mg of quercetin equivalents/g of dry extract). Fifty-seven compounds were identified by LC-DAD-ESI-MS analysis, belonging mainly to the class of flavones (32.27%), with luteolin 7-(6″-acetylglucoside) as the most abundant compound and phenolic acids (32.54%), with salvianolic acid C as the most abundant compound. A conspicuous presence of phenylethanoids (15.26%) was also found, of which the major constituent is forsythoside B. PCME showed a strong antioxidant activity with half-inhibitory activity (IC50) ranging from 1.88 to 37.88 μg/mL and a moderate iron chelating activity (IC50 327.44 μg/mL). PCME appears to be safe with Lethal Dose 50 (LD50) ≥ 2000 mg/kg b.w. No mortality or toxicity signs, including any statistically significant changes in body weight gain and relative organs' weight with respect to the control group, were recorded. A significant (p < 0.001) wound contraction was observed in the 5% PCMO-treated group with respect to the untreated and petroleum jelly groups between 8 and 20 days, whereas no statistically significant results were observed at the two lower doses (1 and 2% PCMO). In addition, the 5% PCMO-treated group showed a statistically significant (p < 0.05) wound healing activity with respect to the reference drug-treated group, showing, at the end of the study, the highest wound contraction percentage (88.00 ± 0.16%).

CONCLUSION

PCME was safe and showed strong antioxidant and wound-healing properties, suggesting new interesting pharmaceutical applications for P. crinita based on its traditional use.

Phytocompounds from Amazonian Plant Species against Acute Kidney Injury: Potential Nephroprotective Effects

There are several Amazonian plant species with potential pharmacological validation for the treatment of acute kidney injury, a condition in which the kidneys are unable to adequately filter the blood, resulting in the accumulation of toxins and waste in the body. Scientific production on plant compounds capable of preventing or attenuating acute kidney injury-caused by several factors, including ischemia, toxins, and inflammation-has shown promising results in animal models of acute kidney injury and some preliminary studies in humans. Despite the popular use of Amazonian plant species for kidney disorders, further pharmacological studies are needed to identify active compounds and subsequently conduct more complex preclinical trials. This article is a brief review of phytocompounds with potential nephroprotective effects against acute kidney injury (AKI). The classes of Amazonian plant compounds with significant biological activity most evident in the consulted literature were alkaloids, flavonoids, tannins, steroids, and terpenoids. An expressive phytochemical and pharmacological relevance of the studied species was identified, although with insufficiently explored potential, mainly in the face of AKI, a clinical condition with high morbidity and mortality.

The Unexplored Wound Healing Activity of Urtica dioica L. Extract: An In Vitro and In Vivo Study

Wound healing is a great challenge in many health conditions, especially in non-healing conditions. The search for new wound healing agents continues unabated, as the use of growth factors is accompanied by several limitations. Medicinal plants have been used for a long time in would healing, despite the lack of scientific evidence veryfying their efficacy. Up to now, the number of reports about medicinal plants with wound healing properties is limited. Urtica dioica L. is a well-known plant, widely used in many applications. Reports regarding its wound healing potential are scant and sparse. In this study, the effect of an Urtica dioica L. extract (containing fewer antioxidant compounds compared to methanolic or hydroalcoholic extracts) on cell proliferation, the cell cycle, and migration were examined. Additionally, antioxidant and anti-inflammatory properties were examined. Finally, in vivo experiments were carried out on full-thickness wounds on Wistar rats. It was found that the extract increases the proliferation rate of HEK-293 and HaCaT cells up to 39% and 30% after 24 h, respectively, compared to control cells. The extract was found to increase the population of cells in the G₂/M phase by almost 10%. Additionally, the extract caused a two-fold increase in the cell migration rate of both cell lines compared to control cells. Moreover, the extract was found to have anti-inflammatory properties and moderate antioxidant properties that augment its overall wound healing potential. Results from the in vivo experiments showed that wounds treated with an ointment of the extract healed in 9 days, while wounds not treated with the extract healed in 13 days. Histopathological examination of the wound tissue revealed, among other findings, that inflammation was significantly reduced compared to the control. Urtica dioica L. extract application results in faster wound healing, making the extract ideal for wound healing applications and a novel drug candidate for wound healing.

Changes in Human Erythrocyte Membrane Exposed to Aqueous and Ethanolic Extracts from Uncaria tomentosa

Uncaria tomentosa (Willd.) DC is a woody climber species originating from South and Central America that has been used in the therapy of asthma, rheumatism, hypertension, and blood purification. Our previous study showed that U. tomentosa extracts altered human erythrocyte shape, which could be due to incorporation of the compounds contained in extracts into the erythrocyte membrane. The aim of the present study was to determine how the compounds contained in U. tomentosa extracts incorporate into the human erythrocyte membrane. The study has assessed the effect of aqueous and ethanolic extracts from leaves and bark of U. tomentosa on the osmotic resistance of the human erythrocyte, the viscosity of erythrocyte interior, and the fluidity of erythrocyte plasma membrane. Human erythrocytes were incubated with the studied extracts in the concentrations of 100, 250, and 500 µg/mL for 2, 5, and 24 h. All extracts tested caused a decrease in erythrocyte membrane fluidity and increased erythrocyte osmotic sensitivity. The ethanolic extracts from the bark and leaves increased viscosity of the erythrocytes. The largest changes in the studied parameters were observed in the cells incubated with bark ethanolic extract. We consider that the compounds from U. tomentosa extracts mainly build into the outer, hydrophilic monolayer of the erythrocyte membrane, thus protecting the erythrocytes against the adverse effects of oxidative stress.

Extracts from Uncaria tomentosa as antiplatelet agents and thrombin inhibitors - The in vitro and in silico study

ETHNOPHARMACOLOGICAL RELEVANCE

A wide range of traditional medicine applications of Uncaria tomentosa (Willd. ex Schult.) DC., commonly known as 'vilcacora' or 'cat's claw', includes blood purification, its anticoagulant properties and its use in haemorrhage therapy.

AIM OF THE STUDY

Our work is devoted to the effects of ethanol and aqueous extracts (1-50 μg/ml) from U. tomentosa leaves and bark on the haemostatic system. The study is based on two main questions: Can these extracts influence the coagulation cascade of blood plasma or the activation of blood platelets? Do they feature any anticoagulant properties?

MATERIALS AND METHODS

Blood platelet aggregation was measured in human platelet-rich plasma; the anticoagulant tests were based on the thrombin, prothrombin and the activated partial thromboplastin time. For the thrombin (TH)-inhibitory activity evaluation, the chromogenic substrate S-2238 and fibrinogen, i.e. physiological substrate for this enzyme, were used. In silico studies included the interactions of TH and the main components of the extracts.

RESULTS

The examined extracts demonstrated slight antiplatelet activity. The thrombin time was slightly prolonged. The most efficient TH inhibitor was the ethanolic fraction from leaves (IC₅₀ = 5.86 and 12.48 μg/ml, for the amidolytic and proteolytic assay, respectively). The plant ingredients interacted with TH within and outside the active site, dependently on the compound. The higher binding affinity was found for procyanidins B2 and C1.

CONCLUSIONS

The examined extracts demonstrated slight antiplatelet effects; however, they may be promising candidates for the natural inhibitors of TH, which is critical for the formation of fibrin clot.

Geissospermiculatine, a New Alkaloid from Geissospermum reticulatum Bark

A new alkaloid, geissospermiculatine was characterized in Geissospermum reticulatum A. H. Gentry bark (Apocynaceae). Here, following a simplified isolation protocol, the structure of the alkaloid was elucidated through GC-MS, LC-MS/MS, 1D, and 2D NMR (COSY, ROESY, HSQC, HMBC, ¹H-¹⁵N HMBC). Cytotoxic properties were evaluated in vitro on malignant THP-1 cells, and the results demonstrated that the cytotoxicity of the alkaloid (30  μg/mL) was comparable with staurosporine (10  μM). Additionally, the toxicity was tested on zebrafish (Danio rerio) embryos in vivo by monitoring their development (0–72 h); toxicity was not evident at 30  μg/mL.

Uncaria tomentosa improves cognition, memory and learning in middle-aged rats

Aging accelerates neurodegeneration, while natural and safe neuroprotective agents, such as Uncaria tomentosa, may help to overcome this problem. This study assessed the effects of U. tomentosa extract treatment on the aging process in the brain of Wistar rats. The spatial memory and learning, acetylcholinesterase (AChE) activity, and DNA damage were assessed. Animals of 14 months were tested with different doses of U. tomentosa (5 mg/kg, 15 mg/kg, and 30 mg/kg) and with different durations of treatment (one month and one year). In the Morris Water Maze (MWM), the escape latency was significantly (p < 0.0001) shorter in rats that received 5 mg/kg, 15 mg/kg, and 30 mg/kg of U. tomentosa for both one month and one year of treatment. There was a significant difference in time spent at the platform zone (p < 0.05) of the middle-aged rats treated with U. tomentosa extract for one year when compared to the control rats. The cortex and hippocampus of rats treated with U. tomentosa for one year showed significant (p > 0.05) reduction in AChE activity. DNA damage index on cortex was significantly lower (p < 0.05) in animals treated with 30 mg/kg of U. tomentosa for one month while all the tested doses demonstrated significant (p < 0.001) reductions in DNA damage index in animals treated for one year. In conclusion, U. tomentosa may represent a source of phytochemicals that could enhance memory activity, repair DNA damage, and alter AChE activity, thereby providing neuroprotection during the aging process.

Antioxidant Activity of an Aqueous Leaf Extract from Uncaria tomentosa and Its Major Alkaloids Mitraphylline and Isomitraphylline in Caenorhabditis elegans

Uncaria tomentosa (Rubiaceae) has a recognized therapeutic potential against various diseases associated with oxidative stress. The aim of this research was to evaluate the antioxidant potential of an aqueous leaf extract (ALE) from U. tomentosa, and its major alkaloids mitraphylline and isomitraphylline. The antioxidant activity of ALE was investigated in vitro using standard assays (DPPH, ABTS and  FRAP), while the in vivo activity and mode of action were studied using Caenorhabditis elegans as a model organism. The purified alkaloids did not exhibit antioxidant effects in vivo. ALE reduced the accumulation of reactive oxygen species (ROS) in wild-type worms, and was able to rescue the worms from a lethal dose of the pro-oxidant juglone. The ALE treatment led to a decreased expression of the oxidative stress response related genes sod-3, gst-4, and hsp-16.2. The treatment of mutant worms lacking the DAF-16 transcription factor with ALE resulted in a significant reduction of ROS levels. Contrarily, the extract had a pro-oxidant effect in the worms lacking the SKN-1 transcription factor. Our results suggest that the antioxidant activity of ALE in C. elegans is independent of its alkaloid content, and that SKN-1 is required for ALE-mediated stress resistance.

Polyphenolic Composition and Antioxidant Activity of Uncaria tomentosa Commercial Bark Products

Uncaria tomentosa, which is widely commercialized as an herbal medicine, constitutes an important source of secondary metabolites with diverse biological activities. For instance, we have previously reported, for the first time, of a polyphenolic profile rich in proanthocyanidins from extracts of U. tomentosa plants, as well as their antioxidant capacity, antimicrobial activity on aerial bacteria, and cytotoxicity on cancer cell lines. These promising results prompted this research to evaluate the polyphenolic contents of U. tomentosa commercial products. We report a detailed study on the polyphenolic composition of extracts from U. tomentosa bark products (n = 18) commercialized in Costa Rica and Spain. Using HPLC-DAD/TQ-ESI-MS, a total of 25 polyphenolic compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavan-3-ol monomers, procyanidin dimers, procyanidin trimers, as well as propelargonidin dimers. Our findings on the polyphenolic profile for all commercial samples show analogous composition to previous reports on U. tomentosa bark material, for instance a 41–49% content of procyanidin dimers and the presence of propelargonidin dimers (8–15%). However, most of the 18 commercial samples exhibit low proanthocyanidin contents (254.8–602.8 µg/g), more similar to previous U. tomentosa inner bark reports, while some exhibit better results, with one sample (SP-2) showing the highest contents (2386.5 µg/g) representing twice the average value of all 18 commercial products. This sample also exhibits the highest total phenolics (TP) and total proanthocyanidins (PRO) contents, as well as the highest Oxygen Radical Absorbance Capacity (ORAC) value (1.31 µg TE/g). One-way Analysis of Variance (ANOVA) with a Tukey post hoc test indicated significant difference (p < 0.05) between products from Costa Rica and Spain for TP and PRO findings, with samples from Spain exhibiting a higher average value. In addition, Pearson correlation analysis results showed a positive correlation (p < 0.05) between TP, PRO, and ORAC results, and an especially important correlation between ORAC antioxidant values and procyanidin dimers (r = 0.843, p < 0.05), procyanidin trimers (r = 0.847, p < 0.05), and propelargonidin dimers (r = 0.851, p < 0.05) contents. Finally, Principal Component Analysis (PCA) results indicated some variability in the composition regardless of their origin. However, only one sample (SP-2) stands out significatively, showing the highest PC1 because of its particularly high proanthocyanidins contents, which could be attributed to the 15% bark polyphenolic extract labeled in this commercial product, which differentiate this sample from all other 17 commercial samples. Therefore, our findings confirmed previous results on the value of extracts in the elaboration of potential commercial products from U. tomentosa, rich in proanthocyanidins and exhibiting high antioxidant activity.

Polyphenolic Composition and Antioxidant Activity of Aqueous and Ethanolic Extracts from Uncaria tomentosa Bark and Leaves

Uncaria tomentosa constitutes an important source of secondary metabolites with diverse biological activities mainly attributed until recently to alkaloids and triterpenes. We have previously reported for the first-time the polyphenolic profile of extracts from U. tomentosa, using a multi-step process involving organic solvents, as well as their antioxidant capacity, antimicrobial activity on aerial bacteria, and cytotoxicity on cancer cell lines. These promising results prompted the present study using food grade solvents suitable for the elaboration of commercial extracts. We report a detailed study on the polyphenolic composition of aqueous and ethanolic extracts of U. tomentosa bark and leaves (n = 16), using High Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-DAD/TQ-ESI-MS). A total of 32 compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavan-3-ols monomers, procyanidin dimers and trimers, flavalignans⁻cinchonains and propelargonidin dimers. Our findings showed that the leaves were the richest source of total phenolics and proanthocyanidins, in particular propelargonidin dimers. Two-way Analysis of Variance (ANOVA) indicated that the contents of procyanidin and propelargonidin dimers were significantly different (p < 0.05) in function of the plant part, and leaves extracts showed higher contents. Oxygen Radical Absorbance Capacity (ORAC) and 2,2-diphenyl-1-picrylhidrazyl (DPPH) values indicated higher antioxidant capacity for the leaves (p < 0.05). Further, correlation between both methods and procyanidin dimers was found, particularly between ORAC and propelargonidin dimers. Finally, Principal Component Analysis (PCA) analysis results clearly indicated that the leaves are the richest plant part in proanthocyanidins and a very homogenous material, regardless of their origin. Therefore, our findings revealed that both ethanol and water extraction processes are adequate for the elaboration of potential commercial extracts from U. tomentosa leaves rich in proanthocyanidins and exhibiting high antioxidant activity.

In vitro synergism of a water insoluble fraction of Uncaria tomentosa combined with fluconazole and terbinafine against resistant non-Candida albicans isolates

CONTEXT

Uncaria tomentosa D.C. (Rubiaceae) has several biological activities, including activity against resistant Candida strains. The synergistic interaction with terbinafine or fluconazole can be an important alternative to overcome this resistance.

OBJECTIVES

The potential synergy between a water insoluble fraction (WIF) from Uncaria tomentosa bark and the antifungals terbinafine (TRB) and fluconazole (FLZ) against non-Candida albicans resistant strains was investigated.

MATERIALS AND METHODS

TRB and FLZ, alone and combined with WIF, were tested by the checkerboard procedure using the micro-dilution technique against seven isolates of Candida glabrata and C. krusei. The molecular interactions occurring outside the cell wall were evaluated by scanning electron microscopy, Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC) analysis.

RESULTS

The checkerboard inhibitory assay demonstrated synergy for WIF:TRB and WIF:FLZ combinations, respectively. The best synergistic cell damage was demonstrated unequivocally for the associations of WIF and TRB (1.95:4.0 μg/mL) and WIF and FLZ (1.95:8.0 μg/mL). The comparison of the FT-IR spectra of the antifungal alone, and in combination with WIF, allows recognizing clear differences in 3000, 1600, 1400, and 700-800 cm^-1 bands. Additionally, modifications on TRB and FLZ thermograms were clearly noticed after their combination with WIF.

CONCLUSIONS

DSC and infrared analysis demonstrated intermolecular interactions between WIF and either TRB or FLZ. Hence, quite likely the synergistic effect is related to interaction events occurring outside the cell wall between antifungal and cat's claw proanthocyanidins. A direct action on the cell wall is suggested, without connection with the ABC efflux pump mechanism.

Proanthocyanidin Characterization and Bioactivity of Extracts from Different Parts of Uncaria tomentosa L. (Cat's Claw)

Apart from alkaloids, bioactive properties of Uncaria tomentosa L. have been attributed to its phenolic constituents. Although there are some reports concerning low-molecular-weight polyphenols in U. tomentosa, its polymeric phenolic composition has been scarcely studied. In this study, phenolic-rich extracts from leaves, stems, bark and wood (n = 14) of Uncaria tomentosa plants from several regions of Costa Rica were obtained and analysed in respect to their proanthocyanidin profile determined by a quadrupole-time-of-flight analyser (ESI-QTOF MS). Main structural characteristics found for U. tomentosa proanthocyanidins were: (a) monomer composition, including pure procyanidins (only composed of (epi)catechin units) and propelargonidins (only composed of (epi)afzelechin units) as well as mixed proanthocyanidins; and (b) degree of polymerization, from 3 up to 11 units. In addition, U. tomentosa phenolic extracts were found to exhibit reasonable antioxidant capacity (ORAC (Oxygen Radical Absorbance Capacity) values between 1.5 and 18.8 mmol TE/g) and antimicrobial activity against potential respiratory pathogens (minimum IC50 of 133 µg/mL). There were also found to be particularly cytotoxic to gastric adenocarcinoma AGS and colon adenocarcinoma SW620 cell lines. The results state the particularities of U. tomentosa proanthocyanidins and suggest the potential value of these extracts with prospective use as functional ingredients.

Rapid determination of oxindole alkaloids in cat's claw by HPLC using ionic liquid-based microwave-assisted extraction and silica monolithic column

Cat's claw is a large woody vine with hook-like thorns, and has been traditionally used to treat inflammatory disorders in South and Central America. In this study, a rapid, validated high-performance liquid chromatographic (HPLC) method using a silica monolithic column was developed for the simultaneous determination of oxindole alkaloids, namely rhynchophylline, pteropodine, isomitraphylline and isopteropodine, in cat's claw. The ionic liquid-based microwave-assisted extraction (ILMAE), considered as an environmentally friendly and powerful tool, was first applied in the extraction of oxindole alkaloids. To optimize the HPLC method, the stationary phases, pH values of mobile phase and flow rates were investigated. The validated HPLC method using a Monolithic RP_18e column (100 × 4.6 mm) enables these analytes to be separated almost twice as fast as with a conventional particulate column (~16 vs ~30 min) with limits of quantification and detection of 0.5 and 0.15 μg/mL, respectively. The ILMAE conditions were optimized by the Taguchi orthogonal array design. In comparison with conventional water boiling extraction, ILMAE offers almost four times higher yields within an extremely short extraction time. The developed HPLC coupled with ILMAE method could be efficient and practical for rapid determination of oxindole alkaloids in cat's claw.

Uncaria tomentosa (Willd. ex Schult.) DC (Rubiaceae) Sensitizes THP-1 Cells to Radiation-induced Cell Death

Background:

Uncaria tomentosa (Willd. ex Schult.) DC (Rubiaceae), known as Cat's Claw or Uña de gato, is a traditionally used medicinal plant native to Peru. Some studies have shown that U. tomentosa can act as an antiapoptotic agent and enhance DNA repair in chemotherapy-treated cells although others have shown that U. tomentosa enhanced apoptosis.

Objective:

To determine if treatment with U. tomentosa can significantly enhance cell death in THP-1 cells exposed to ionizing radiation.

Materials and Methods:

THP-1 monocyte-like cells were treated with ethanolic extracts of U. tomentosa in the presence or absence of bacterial lipopolysaccharide and then exposed to ionizing radiation. Cell proliferation was assessed by MTT and clonogenic assays and the effects on cell cycle measured by flow cytometry and immunoblotting. Changes in cell signaling were determined by immunoblotting and cytokine ELISA and activation of apoptosis measured by caspase activation and DNA fragmentation analysis.

Results:

Treatment of THP-1 cells with U. tomentosa had a small effect on cell proliferation. However, when the U. tomentosa-pretreated cells were also subjected to 5–9 Gy ionizing radiation, they showed a significant decrease in cell proliferation and increased cellular apoptosis as measured by DNA fragmentation and caspase activation. Treatment with U. tomentosa also decreased the expression of Cyclin E and Cyclin B, key regulators of normal cell cycle progression, and decreased the phosphorylation of various stress-activated, cell survival proteins including p38, ERK, and SAP/JNK kinase.

Conclusions:

These results suggest that U. tomentosa could be useful in enhancing cell death following anticancer therapies including ionizing radiation.

SUMMARY

Treatment of THP-1 cells with Uncaria tomentosa increases their susceptibility to X-rays. The combination of Uncaria tomentosa and X-ray exposure strongly inhibits cell signaling and promotes apoptosis.

Abbreviations Used: LPS: Lipopolysaccharide, TNF: Tumor necrosis factor: IL-1, Interleukin-1: SDS: Sodium dodecylsulphate, TBS: Tris-buffered saline.

Uncaria tomentosa extract alters the catabolism of adenine nucleotides and expression of ecto-5'-nucleotidase/CD73 and P2X7 and A1 receptors in the MDA-MB-231 cell line

ETHOPHARMACOLOGICAL RELEVANCE

Uncaria tomentosa (Willd.) DC. (Rubiaceae) (Ut), also known as cat's claw, is a woody liana widely spread throughout the Amazon rainforest of Central and South America, containing many chemical constituents such as oxindole alkaloids, which are responsible for various biological activities. Since ancient times, the indigenous people of Peru have used it as a bark infusion for the treatment of a wide range of health problems gastric ulcers, arthritis and rheumatism. Recently, Ut is distributed worldwide and used as an immunomodulatory and anti-inflammatory herbal remedy. Additionally, U. tomentosa also has antitumural activity. However, little is known about the action of U. tomentosa on the purinergic system mechanisms, which is involved in tumor progression.

AIM OF THE STUDY

Considering the pharmacological properties of U. tomentosa, we sought to evaluate the hydroalcoholic extract U tomentosa is able to influence the purinergic system in breast cancer cells, MDA-MB-231. Through the activity and expression of ectonucleotidases (NTPDase - CD39; Ecto-5'-nucleotidase - CD73) and purinergic repceptores (P2X7 and A1).

MATERIALS AND METHODS

A hydroalcoholic extract was prepared in two concentrations, 250 and 500μg/mL. (Ut250; Ut500). The effect of these concentrations on the activity and expression of ectonucleotidases, as well as on the density of purinergic receptors were investigated in MDA-MB-231 breast cancer cells. Cells were treated with the hydroalcoholic extract of Uncaria tomentosa and/or doxorubicin (Doxo 1μM; Ut250+Doxo; Ut500+Doxo) for 24h.

RESULTS

Although the results were not significant for the hydrolysis of the ATP, they presented an increase in the ADP hydrolysis in the Ut500+Doxo group when compared to the control group. Additionally, the activity of 5'-nucleotidase was inhibited in all groups when compared with the untreated group of cells. Inhibition of the enzyme was more evident in groups with U. tomentosa per se. The expression of CD39 was increased in the Ut250 and Ut250+Doxo groups when compared to the control group. No changes were found in the CD73 expression. Furthermore, a reduction in the density of the P2X7 receptor in all treated groups was detected. On the other hand, the density of the A1 receptor increased in all groups compared to the control group, with the exception of the Ut500+Doxo group.

CONCLUSION

Therefore, we conclude that hydroalcoholic extract of U. tomentosa may be responsible for the reduction of adenosine levels in the extracellular medium, which accelerates tumor progression. Interestingly, the dysregulation of A1 and P2X7 receptors in the MDA-MB-231 cells exacerbate the proliferation of this cells and U. tomentosa treatment may be stimulate the antitumor activity of adenosine A1 receptor and control the P2X7 effects. Our study demonstrates the significant participation of purinergic pathway in the regulation of MDA-MB-231 progression; additionally, U. tomentosa treatment alone or combined with chemotherapy may favor the action of doxorubicin.

In vitro anti-acetylcholinesterase activity of an aqueous extract of Unicaria tomentosa and in silico study of its active constituents

Depletion of acetylcholine in the central nervous system (CNS) is responsible for memory loss and cognition deficit. Enzyme acetylcholinesterase (AChE) is responsible for destruction of acetylcholine (Ach) in the brain. Many herbal plant extracts have been investigated for their potential use in the treatment of Alzheimer's disease (AD) by inhibiting AChE and upregulating the levels of Ach. The current study investigated the anti-acetylcholinesterase (AChE) activity of an aqueous extract of Unicaria tomentosa bark which has not been reported so far in the literature. The in vitro study of an aqueous extract of U. tomentosa showed maximum inhibition of 76.2±0.002 % at 0.4mg/ml of final concentration with an IC50 = 0.112 mg/ml. The mechanism of inhibition was elucidated by kinetic study which showed mixed type of inhibition, this might be due to the presence of various phytoconstituents such as oxindole alkaloids present in an aqueous extract. Based on molecular structure of phytoconstituents obtained from U. tomentosa known from the relevant literature, in-silico molecular docking study was performed against AChE protein to validate the results.

Antimutagenic and antioxidant effects of a South African traditional formulation used as an immune booster

Abstract The traditional medicines sector in South Africa is still largely unregulated despite legislation aimed at regulating the practice being in place. The HIV and AIDS epidemic has fuelled demand for traditional medicines, with many patients consulting traditional health practitioners who offer different treatments, including herbal immune boosters. This study investigated the mutagenic and antioxidant effects of the widely sold herbal immune booster, uMakhonya®. The Ames test was used for analysis of the genototoxic effects while the adenosine triphosphate (ATP) assay was used to evaluate cell cytotoxicity in peripheral blood mononuclear cells (PBMCs) and THP-1 monocytes. To evaluate the antioxidant effects the malondialdehyde (MDA) quantification, the nitric oxide and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assays were used. UMakhonya® doses of up to 5000 μg/mL were not genotoxic in the Ames test. UMakhonya® was shown to induce dose-dependent cytotoxicity in both PBMCs and THP-1 cells with doses ranging from 500 μg/ mL to 1000 μg/mL, showing significant (p less than 0.05) toxicity. UMakhonya® was able to significantly (p less than 0.05) reduce nitrite radicals at 100 μg/mL while lower doses were not effective when compared to samples stimulated by lipopolysaccharide only. Non-cytotoxic doses of uMakhonya® showed significant (p less than 0.05) lipid peroxide scavenging ability in supernatants while this scavenging ability was considerably reduced intracellularly. In the DPPH assay, when both uMakhonya® and ascorbic acid were reconstituted in buffered saline, the traditional herbal remedy showed better radical scavenging abilities. Therefore further studies on the genotoxicity of uMakhonya®, when metabolically activated, and its antioxidant effects in in-vivo models are warranted

Medicinal uses, phytochemistry and pharmacology of the genus Uncaria

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Uncaria belongs to the family Rubiaceae, which mainly distributed in tropical regions, such as Southeast Asia, Africa and Southeast America. Their leaves and hooks have long been thought to have healing powers and are already being tested as a treatment for asthma, cancer, cirrhosis, diabetes, hypertension, stroke and rheumatism. The present review aims to provide systematically reorganized information on the ethnopharmacology, phytochemistry and pharmacology of the genus Uncaria to support for further therapeutic potential of this genus. To better understanding this genus, information on the stereo-chemistry and structure-activity relationships in indole alkaloids is also represented.

MATERIAL AND METHODS

The literature study of this review is based on various databases search (SCIFinder, Science Direct, CNKI, Wiley online library, Spring Link, Web of Science, PubMed, Wanfang Data, Medalink, Google scholar, ACS, Tropicos, Council of Heads of Australasian Herbaria, The New York Botanical Garden, African Plants Database at Genera Botanical Garden, The Plant List and SEINet) and library search for Biological Abstract and some local books on ethnopharmacology.

RESULTS

19 species of the genus Uncaria are found to be important folk medicines in China, Malaysia, Phillippines, Africa and Southeast America, etc, and have been served for the treatment of asthma, rheumatism, hyperpyrexia, hypertension and headaches, etc. More than 200 compounds have been isolated from Uncaria, including indole alkaloids, triterpenes, flavonoids, phenols, phenylpropanoids, etc. As characteristic constituents, indole alkaloids have been considered as main efficacy component for hypertension, epilepsy, depressant, Parkinson's disease and Alzheimer's disease. In addition, pharmacokinetic and metabolism investigation reveal that the indole alkaloids are likely to be absorbed, metabolized and excreted at early time points. Moreover, the specific inhibition of CYP isozymes can regulate their hydroxylation metabolites at C-10 and C-11.

CONCLUSION

Preliminary investigations on pharmacological properties of the Uncaria species have enlightened their efficacious remedy for hypertension, asthma, cancer, diabetes, rheumatism and neurodegenerative diseases. To ensure the safety and effectiveness in clinical application, research on bioactive compounds, pharmacological mechanisms and toxicity of the genus Uncaria as well as the stereo-chemistry and structure-activity relationships of indole alkaloids seem very important.

Effect of Uncaria tomentosa extract on purinergic enzyme activities in lymphocytes of rats submitted to experimental adjuvant arthritis model

BACKGROUND

Considering that adjuvant arthritis is an experimental model of arthritis widely used for preclinical testing of numerous anti-arthritic agents, which were taken by a large number of patients worldwide, it is of great interest to investigate the therapeutic action of compounds with anti-inflammatory properties, such as Uncaria tomentosa extract. Moreover, there are no studies demonstrating the effect of U. tomentosa on the metabolism of adenine nucleotides published so far. Thus, the purpose of the present study is to investigate the effects of U. tomentosa extract on E-NTPDase and E-ADA activities in lymphocytes of Complete Freund's Adjuvant (CFA) arthritis induced rats.

METHODS

To evaluate the effect of U. tomentosa extract on the activity of E-NTPDase and ADA in lymphocytes, the rats were submitted to an experimental adjuvant arthritis model. Peripheral lymphocytes were isolated and E-NTPDase and E-ADA activities were determined. Data were analyzed by a one- or two-way ANOVA. Post hoc analyses were carried out by the Student-Newman-Keuls (SNK) Multiple Comparison Test.

RESULTS

E-NTPDase activity was increased in arthritic untreated. Arthritic rats which received U. tomentosa extract, presented similar results to the control group. However, results obtained for adenosine hydrolysis by E-ADA were not altered in arthritic rats. U. tomentosa extract did not alter E-NTPDase and E-ADA activity in healthy animals.

CONCLUSIONS

The present investigation supports the hypothesis that the increased E-NTPDase activity verified in arthritic rats might be an attempt to maintain basal levels of ATP and ADP in the extracellular medium, since the arthritis induction causes tissue damage and, consequently, large amounts of ATP are released into this milieu. Also, it highlights the possibility to use U. tomentosa extract as an adjuvant to treat arthritis.

Significance of antioxidant potential of plants and its relevance to therapeutic applications

Oxidative stress has been identified as the root cause of the development and progression of several diseases. Supplementation of exogenous antioxidants or boosting endogenous antioxidant defenses of the body is a promising way of combating the undesirable effects of reactive oxygen species (ROS) induced oxidative damage. Plants have an innate ability to biosynthesize a wide range of non-enzymatic antioxidants capable of attenuating ROS- induced oxidative damage. Several in vitro methods have been used to screen plants for their antioxidant potential, and in most of these assays they revealed potent antioxidant activity. However, prior to confirming their in vivo therapeutic efficacy, plant antioxidants have to pass through several physiopharmacological processes. Consequently, the findings of in vitro and in vivo antioxidant potential assessment studies are not always the same. Nevertheless, the results of in vitro assays have been irrelevantly extrapolated to the therapeutic application of plant antioxidants without undertaking sufficient in vivo studies. Therefore, we have briefly reviewed the physiology and redox biology of both plants and humans to improve our understanding of plant antioxidants as therapeutic entities. The applications and limitations of antioxidant activity measurement assays were also highlighted to identify the precise path to be followed for future research in the area of plant antioxidants.

Effect of Uncaria tomentosa Extract on Apoptosis Triggered by Oxaliplatin Exposure on HT29 Cells

Background/Aim. The use of herbal products as a supplement to minimize the effects of chemotherapy for cancer treatment requires further attention with respect to the activity and toxicity of chemotherapy. Uncaria tomentosa extract, which contains oxindole alkaloids, is one of these herbal products. The objective of this study was to evaluate whether Uncaria tomentosa extract modulates apoptosis induced by chemotherapy exposure. Materials and Methods. Colorectal adenocarcinoma cells (HT29 cells) were grown in the presence of oxaliplatin and/or Uncaria tomentosa extract. Results. The hydroalcoholic extract of Uncaria tomentosa enhanced chemotherapy-induced apoptosis, with an increase in the percentage of Annexin positive cells, an increase in caspase activities, and an increase of DNA fragments in culture of the neoplastic cells. Moreover, antioxidant activity may be related to apoptosis. Conclusion. Uncaria tomentosa extract has a role for cancer patients as a complementary therapy. Further studies evaluating these beneficial effects with other chemotherapy drugs are recommended.

Effect of an herbal/botanical supplement on strength, balance, and muscle function following 12-weeks of resistance training: a placebo controlled study

BACKGROUND

StemSport (SS; StemTech International, Inc. San Clemente, CA) contains a proprietary blend of the botanical Aphanizomenon flos-aquae and several herbal antioxidant and anti-inflammatory substances. SS has been purported to accelerate tissue repair and restore muscle function following resistance exercise. Here, we examine the effects of SS supplementation on strength adaptations resulting from a 12-week resistance training program in healthy young adults.

METHODS

Twenty-four young adults (16 males, 8 females, mean age = 20.5 ± 1.9 years, mass = 70.9 ± 11.9 kg, stature = 176.6 ± 9.9 cm) completed the twelve week training program. The study design was a double-blind, placebo controlled parallel group trial. Subjects either received placebo or StemSport supplement (SS; mg/day) during the training. 1-RM bench press, 1-RM leg press, vertical jump height, balance (star excursion and center of mass excursion), isokinetic strength (elbow and knee flexion/extension) and perception of recovery were measured at baseline and following the 12-week training intervention.

RESULTS

Resistance training increased 1-RM strength (p < 0.008), vertical jump height (p < 0.03), and isokinetic strength (p < 0.05) in both SS and placebo groups. No significant group-by-time interactions were observed (all p-values >0.10).

CONCLUSIONS

These data suggest that compared to placebo, the SS herbal/botanical supplement did not enhance training induced adaptations to strength, balance, and muscle function above strength training alone.

Antimutagenic and antiherpetic activities of different preparations from Uncaria tomentosa (cat's claw)

Uncaria tomentosa have been used to treat viral diseases such as herpes due to multiple pharmacological effects, but its therapeutic efficacy against this virus have not been reported yet. Thus, in vitro antiherpetic activity of hydroethanolic extract from barks, purified fractions of quinovic acid glycosides and oxindole alkaloids was evaluated by plaque reduction assay, including mechanistic studies (virucidal, attachment and penetration action). Once exposure to physical agents might lead to reactivation of the herpetic infection, antimutagenic effect (pre-, simultaneous and post-treatment protocols) was also evaluated by Comet assay. The antiherpetic activity from the samples under investigation seemed to be associated with the presence of polyphenols or their synergistic effect with oxindole alkaloids or quinovic acid glycosides, once both purified fractions did not present activity when evaluated alone. Inhibition of viral attachment in the host cells was the main mechanism of antiviral activity. Although both purified fractions displayed the lowest antimutagenic activity in pre and simultaneous treatment, they provided a similar effect to that of cat's claw hydroethanolic extract in post-treatment. Given that purified fractions may result in a reduced antiherpetic activity, the use of cat's claw hydroethanolic extract from barks should be prioritized in order to obtain a synergistic effect.

Anti-inflammatory and antitumoural effects of Uncaria guianensis bark

ETHNOPHARMACOLOGICAL RELEVANCE

Uncaria guianensis (Aublet) Gmell (Rubiaceae) is a medicinal plant from the jungles of South and Central America, used to treat cancer, arthritis, diabetes, and inflammation. Evaluate the anti-inflammatory and anti-tumor effects of Uncaria guianensis preparations.

MATERIALS AND METHODS

Bio-guided fractionation of a hydroethanolic extract of Uncaria guianensis was performed, evaluating the fractions and subfractions for their effect on inflammatory mediators, tumour necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and prostaglandin E2 (PGE2) by ELISA and nitric oxide (NO) by the Griess reaction in cultured supernatant from RAW 264.7 macrophages stimulated with lipopolysaccharide (LPS). The expression of cyclooxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS) and inhibitor of κB (IκB) were investigated in RAW 264.7 macrophages by flow cytometry. The activity of NF-κB in HeLa cells transfected with a luciferase reporter system was determined. The effect of Uncaria guianensis on the inflammatory response in vivo was assessed in BALB/c mice stimulated with LPS, on rat paw oedema induced by carrageenan, and on tumour growth and lung metastasis in BALB/c mice inoculated with 4T1 mammary tumour cells. Immune cell infiltrates and inflammatory mediators were evaluated in the tumour by immunohistochemistry.

RESULTS

Sub-fraction Ug AIV inhibited, to varying degrees, NO, TNF-α, IL-6 and PGE2 production by macrophages in vitro (30 μg/ml) and in the serum of LPS-challenged mice (5 mg/kg). Macrophage expression of Cox-2 was inhibited (35%), IκB degradation was completely inhibited and NF-κB activation was inhibited (70%) by Ug AIV at 30 μg/ml. Ug AIV decreased paw oedema by 86% (5 mg/kg) and serum NO and TNF-α by 45% and 65% respectively. Ug AIV reduced 4T1 mammary tumour growth by 91% on day 33 post-inoculation as well as the levels of serum NO, IL-6 and TNF-α in the same animals. Ug AIV decreased the number of tumour-infiltrating T lymphocytes, macrophages and neutrophils as well as the number of cells positive for COX-2, iNOS, IL-6, TNF-α and p65.

CONCLUSIONS

As Ug AIV was not cytotoxic for tumour cells or macrophages, its anti-tumour effect may be due to a reduction in pro-tumoural inflammatory processes in the tumour microenvironment, possibly mediated through NF-κB.

Uncaria tomentosa Alkaloidal Fraction Reduces Paracellular Permeability, IL-8 and NS1 Production on Human Microvascular Endothelial Cells Infected with Dengue Virus

Dengue is the major Arbovirus in the world, annually causing morbidity and death. Severe dengue is associated with changes in the endothelial barrier function due to the production of inflammatory mediators by immune cells and by the endothelium. Dengue virus (DENV) replicates efficiently in human endothelial cells in vitro and elicits immune responses resulting in endothelial permeability. Uncaria tomentosa (Willd.) DC.(Rubiaceae), known as cat's claw, has been used in folk medicine for the treatment of a wide-array of symptoms, and several scientific studies reported its antiviral, immunomodulatory, anti-inflammatory and antioxidant properties. Here we infected a human lineage of dermal microvascular endothelial cells (HMEC-1) with DENV-2 and treated it with an alkaloidal fraction from U. tomentosa bark (AFUT). We showed antiviral and immunomodulatory activities of U. tomentosa by determining the NS1 antigen and IL-8 in supernatant of DENV-2 infected HMEC-1. Furthermore, by measurement of transendothelial electrical resistance (TEER) we demonstrated, for the first time, that a plant derivative contributed to the reduction of paracellular permeability in DENV-2 infected HMEC-1. We also showed that IL-8 contributed significantly to the induction of permeability. Although further investigations should be conducted before a new drug can be suggested, our in vitro data support evidence that AFUT could be potentially useful in developing a treatment for severe dengue.

Herbal medicine and acupuncture for breast cancer palliative care and adjuvant therapy

Breast cancer is a life-threatening disease among women worldwide with annual rates of reported incidence and death increasing alarmingly. Chemotherapy is a recommended and effective treatment option for breast cancer; however, the narrow therapeutic indices and varied side effects of currently approved drugs present major hurdles in increasing its effectiveness. An increasing number of literature evidence indicate that complementary and alternative medicine (CAM) used in treatment-related symptom control and alleviation of side effects plays an important role in increasing survival rate and quality of life in breast cancer patients. This review focuses on the use of herbal medicines and acupuncture in palliative care and as adjuvants in the treatment of breast cancer. Herbal medicinal treatments, the correlation of clinical use with demonstrated in vitro and in vivo mechanisms of action, and the use of certain acupoints in acupuncture are summarized. The aim of this review is to facilitate an understanding of the current practice and usefulness of herbal medicine and acupuncture as adjuvants in breast cancer therapy.

Effect of lavender essential oil on LPS-stimulated inflammation

Lavender essential oil (LEO) is one the most favorite and widely used essential oils in aromatherapy. Many studies have demonstrated its functions in calming, assisting sleep, reducing pain and muscular spasms and its antiseptic function. To date, however, the mechanism of LEO on inflammation response is not well understood. In this study, we examined the effect of LEO on 5 μg/ml lipopolysaccharide (LPS) induced inflammation reaction in human monocyte THP-1 cells. We found treatment of 0.1% LEO significantly increased cell viability and inhibited the IL-1β and superoxide anion generation in LPS-stimulated THP-1 cells. Treatment with LEO down-regulated both LPS-induced protein levels of phospho-NF-κB and membrane Toll-like receptor 4. To determine whether the chaperone protein was involved in the reaction, we determined the levels of Heat Shock Protein 70 (HSP70). Our results showed that LEO increased HSP70 expression in LPS-stimulated THP-1 cells, suggesting that the LEO inhibited LPS-induced inflammatory effect might be associated with the expression of HSP70.

Anti-inflammatory activity of Mitraphylline isolated from Uncaria tomentosa bark

ETHNOPHARMACOLOGICAL RELEVANCE

Uncaria tomentosa (Willd. ex Roem. & Schult.) DC. (Rubiaceae) is widely used by populations living in South America to treat many ailments associated with inflammatory disorders. Mitraphylline was shown to be the major pentacyclic oxindolic alkaloid present in the bark chloroformic extract of this plant. Its activity against cytokines involved in inflammation process was tested in a murine model in vivo.

MATERIALS AND METHODS

Mice received mitraphylline once a day for 3 days at 30 mg/kg/day by oral route. Then, they were subjected to bacterial lipopolysaccharide (LPS) endotoxin (15 mg/kg) and the LPS-induced production of 16 different cytokines was determined by Elisa multiplex. Control group received dexamethasone orally at 2mg/kg/day. Toxicity on K565 cells and murine peritoneal macrophages, in vitro, at doses up to 100 μM was monitored by XTT-colorimetric assay.

RESULTS AND CONCLUSIONS

For the first time mitraphylline was tested in vivo against a large range of cytokines that play a crucial role in inflammation. Mitraphylline inhibited around 50% of the release of interleukins 1α, 1β, 17, and TNF-α. This activity was similar to dexamethasone. It also reduced almost 40% of the production of interleukin 4 (IL-4) while the corticoid did not. Lastly it did not show any toxicity on K565 cells nor murine macrophages at doses up to 100 μM.

Studies of biological properties of Uncaria tomentosa extracts on human blood mononuclear cells

ETHNOPHARMACOLOGICAL RELEVANCE

Uncaria tomentosa (Willd.) DC is a lignified climbing plant from South and Central America, which (under the name of "vilcacora" or "cat's claw") has become highly popular in many countries due to its proven immunostimmulatory and anti-inflammatory activities and also with respect to its anticancer and antioxidative effects. There are insufficient data on the mechanism of U. tomentosa action on normal blood mononuclear cells.

AIM OF THE STUDY

The aim of the study was to analyze the impact of ethanol and aqueous extracts from bark and leaves of Uncaria tomentosa on the structure and function of human mononuclear cells and to find out whether the kind of extractant used modulates biological activity of the extracts studied.

MATERIALS AND METHODS

Plant material consisted of four different extracts: (1) ethanol extract from leaves, (2) aqueous extract from leaves, (3) ethanol extract from bark and (4) aqueous extract from bark. The effect of these extracts on protein damage as well as on free-radical formation in human peripheral blood mononuclear cells was analyzed. Moreover, changes in viability, size, and granularity as well as apoptotic alterations in human blood mononuclear cells exposed to U. tomentosa extracts were investigated.

RESULTS

The oxidative changes were observed in mononuclear blood cells exposed to both ethanol and aqueous extracts obtained from bark and leaves. Moreover, in the cells studied the extracts from U. tomentosa induced apoptosis and a decrease in viability of mononuclear blood cells, with the exception of aqueous extract from leaves. Additionally, no statistically significant changes in the cell size were observed both for aqueous extracts from leaves and bark. Changes in the blood mononuclear cell granularity were observed at 250 μg/mL for all extracts examined. The strongest changes were observed for the ethanol extract of the bark, which increased cell granularity at 50 μg/mL and changed cell size at 100 μg/mL.

CONCLUSION

The conducted research showed differences in biological activity between aqueous and ethanol extracts. It was observed that ethanol extracts exhibited stronger negative effects on mononuclear blood cells. The kind of extractant used had a significant influence of the chemical composition of the tested extracts. The ethanol extract from bark containing a high amount of polyphenols and alkaloids revealed the highest pro-apoptotic effect.

Uncaria tomentosa-Adjuvant Treatment for Breast Cancer: Clinical Trial

Breast cancer is the most frequent neoplasm affecting women worldwide. Some of the recommended treatments involve chemotherapy whose toxic effects include leukopenia and neutropenia. This study assessed the effectiveness of Uncaria tomentosa (Ut) in reducing the adverse effects of chemotherapy through a randomized clinical trial. Patients with Invasive Ductal Carcinoma—Stage II, who underwent a treatment regimen known as FAC (Fluorouracil, Doxorubicin, Cyclophosphamide), were divided into two groups: the UtCa received chemotherapy plus 300 mg dry Ut extract per day and the Ca group that only received chemotherapy and served as the control experiment. Blood samples were collected before each one of the six chemotherapy cycles and blood counts, immunological parameters, antioxidant enzymes, and oxidative stress were analyzed. Uncaria tomentosa reduced the neutropenia caused by chemotherapy and was also able to restore cellular DNA damage. We concluded that Ut is an effective adjuvant treatment for breast cancer.

Analysis of alkaloids from different chemical groups by different liquid chromatography methods

Alkaloids are biologically active compounds widely used as pharmaceuticals and synthesised as secondary methabolites in plants. Many of these compounds are strongly toxic. Therefore, they are often subject of scientific interests and analysis. Since alkaloids — basic compounds appear in aqueous solutions as ionized and unionized forms, they are difficult for chromatographic separation for peak tailing, poor systems efficiency, poor separation and poor column-to-column reproducibility. For this reason it is necessity searching of more suitable chromatographic systems for analysis of the compounds. In this article we present an overview on the separation of selected alkaloids from different chemical groups by liquid chromatography thus indicating the range of useful methods now available for alkaloid analysis. Different selectivity, system efficiency and peaks shape may be achieved in different LC methods separations by use of alternative stationary phases: silica, alumina, chemically bonded stationary phases, cation exchange phases, or by varying nonaqueous or aqueous mobile phase (containing different modifier, different buffers at different pH, ion-pairing or silanol blocker reagents). Developments in TLC (NP and RP systems), HPLC (NP, RP, HILIC, ion-exchange) are presented and the advantages of each method for alkaloids analysis are discussed.

Uncaria tomentosa extracts protect human erythrocyte catalase against damage induced by 2,4-D-Na and its metabolites

The effect of ethanolic and aqueous extracts from leaves and bark of Uncaria tomentosa was studied, with particular attention to catalase activity (CAT - EC. 1.11.1.6). We observed that all tested extracts, at a concentration of 250 μg/mL were not toxic to erythrocyte catalase because they did not decreased its activity. Additionally, we investigated the protective effect of extracts on changes in CAT activity in the erythrocytes incubated with sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D-Na) and its metabolites i.e., 2,4-dichlorophenol (2,4-DCP) and catechol. Previous investigations showed that these chemicals decreased activity of erythrocyte catalase (Bukowska et al., 2000; Bukowska and Kowalska, 2004). The erythrocytes were divided into two portions. The first portion was incubated for 1 and 5h at 37°C with 2,4-D-Na, 2,4-DCP and catechol, and second portion was preincubated with extracts for 10 min and then incubated with xenobiotics for 1 and 5h. CAT activity was measured in the first and second portion of the erythrocytes. We found a protective effect of the extracts from U. tomentosa on the activity of catalase incubated with xenobiotics studied. Probably, phenolic compounds contained in U. tomentosa scavenged free radicals, and therefore protected active center (containing -SH groups) of catalase.

Evaluation of the effect of Uncaria tomentosa extracts on the size and shape of human erythrocytes (in vitro)

In this study, we continued our investigations concerning the interaction of Uncaria tomentosa extracts with the human erythrocytes. The analysis of the size and shape of the erythrocytes by means of flow cytometry and phase contrast microscopy was performed. We executed our experiments using ethanolic and aqueous extracts from the leaves and bark of U. tomentosa. Disturbances were observed in the size and shape of the erythrocytes incubated with ethanolic and aqueous extracts at the concentrations of 100 μg/mL and 250 μg/mL, respectively. The observed changes were probably related to the entry of polyphenolic compounds contained in U. tomentosa extracts into erythrocyte membrane. Externalization of phosphatidylserine on the erythrocytic surfaces was also noticed during incubation with extracts at concentration of 250 μg/mL. We concluded that all of the extracts examined induced changes in the erythrocyte membrane properties, whereas ethanolic extracts from bark induced the most significant changes. The possible binding of polyphenols to the erythrocyte surface may have accounted for the protective properties of extracts against haemolysis of RBCs, which was observed in our previous study (Bors et al., 2011), but considerable incorporation of polyphenols into cell membranes can result in disturbance of phosphatidylserine transport and changes in erythrocyte shape. Nevertheless the results of the investigations showed that considerable morphological changes appear only as a result of erythrocyte exposure to high concentrations (50 ppm and 100 ppm) of the extracts studied, thus they should not lead to clinical erythrocytic damage if recommended doses of U. tomentosa preparations are administrated.

Uncaria tomentosa stimulates the proliferation of myeloid progenitor cells

ETHNOPHARMACOLOGICAL RELEVANCE

The Asháninkas, indigenous people of Peru, use cat's claw (Uncaria tomentosa) to restore health. Uncaria tomentosa has antioxidant activity and works as an agent to repair DNA damage. It causes different effects on cell proliferation depending on the cell type involved; specifically, it can stimulate the proliferation of myeloid progenitors and cause apoptosis of neoplastic cells. Neutropenia is the most common collateral effect of chemotherapy. For patients undergoing cancer treatment, the administration of a drug that stimulates the proliferation of healthy hematopoietic tissue cells is very desirable. It is important to assess the acute effects of Uncaria tomentosa on granulocyte-macrophage colony-forming cells (CFU-GM) and in the recovery of neutrophils after chemotherapy-induced neutropenia, by establishing the correlation with filgrastim (rhG-CSF) treatment to evaluate its possible use in clinical oncology.

MATERIALS AND METHODS

The in vivo assay was performed in ifosfamide-treated mice receiving oral doses of 5 and 15 mg of Uncaria tomentosa and intraperitoneal doses of 3 and 9 μg of filgrastim, respectively, for four days. Colony-forming cell (CFC) assays were performed with human hematopoietic stem/precursor cells (hHSPCs) obtained from umbilical cord blood (UCB).

RESULTS

Bioassays showed that treatment with Uncaria tomentosa significantly increased the neutrophil count, and a potency of 85.2% was calculated in relation to filgrastim at the corresponding doses tested. An in vitro CFC assay showed an increase in CFU-GM size and mixed colonies (CFU-GEMM) size at the final concentrations of 100 and 200 μg extract/mL.

CONCLUSIONS

At the tested doses, Uncaria tomentosa had a positive effect on myeloid progenitor number and is promising for use with chemotherapy to minimize the adverse effects of this treatment. These results support the belief of the Asháninkas, who have classified Uncaria tomentosa as a 'powerful plant'.

Uncaria tomentosa for Reducing Side Effects Caused by Chemotherapy in CRC Patients: Clinical Trial

To evaluate the effectiveness of Uncaria tomentosa in minimizing the side effects of chemotherapy and improving the antioxidant status of colorectal cancer (CRC) patients, a randomized clinical trial was conducted. Patients (43) undergoing adjuvant/palliative chemotherapy with 5-Fluorouracil/leucovorin + oxaliplatin (FOLFOX4) were split into two groups: the UT group received chemotherapy plus 300 mg of Uncaria tomentosa daily and the C group received only FOLFOX4 and served as a control. Blood samples were collected before each of the 6 cycles of chemotherapy, and hemograms, oxidative stress, enzymes antioxidants, immunologic parameters, and adverse events were analyzed. The use of 300 mg of Uncaria tomentosa daily during 6 cycles of FOLFOX4 did not change the analyzed parameters, and no toxic effects were observed.

Protective activity of the Uncaria tomentosa extracts on human erythrocytes in oxidative stress induced by 2,4-dichlorophenol (2,4-DCP) and catechol

The purpose of this study was to evaluate the effect of the ethanolic and aqueous extracts of Uncaria tomentosa on human erythrocytes and additionally the assessment of protective effect of these extracts on hemolysis induction, hemoglobin oxidation, and changes in the level of reactive oxygen species (ROS) and lipid peroxidation, which were provoked by selected xenobiotics, i.e. 2,4-dichlorophenol (2,4-DCP) and catechol. All tested extracts, even at a very high concentration of 500 μg/ml were not toxic to the erythrocytes because they did not cause lipid peroxidation, increase methemoglobin and ROS levels nor provoked hemolysis. The results of this study also revealed protective effect of extracts of U. tomentosa. The extracts studied depleted the extent of hemoglobin oxidation and lipid peroxidation as well as decreased the level of ROS and hemolysis, which was provoked by 2,4-DCP. No protective activity of the extracts against catechol action, which is a precursor of semiquinones in cell was found. A difference in the effect of the extracts studied was observed. Ethanol-based extracts revealed more pronounced ability to inhibit oxidation processes in human erythrocytes.

Anticancer activity of the Uncaria tomentosa (Willd.) DC. preparations with different oxindole alkaloid composition

The activity of Uncaria tomentosa preparations on cancer cells was studied using in vitro and in vivo models. IC (50) values were calculated for preparations with different quantitative and qualitative oxindole alkaloid composition: B/W(37) --bark extracted in water at 37 °C, B/W(b)--bark extracted in boiling water, B/50E(37) --bark extracted in 50% ethanol at 37 °C, B/E(b)--bark extracted in boiling 96% ethanol, B/96E(37) --bark extracted in 96% ethanol at 37 °C and B/SRT--bark extracted in water and dichloromethane. Generally, the results obtained showed a high correlation between the total oxindole alkaloid content (from 0.43% to 50.40% d.m.) and the antiproliferative activity of the preparations (IC(50) from >1000 μg/ml to 23.57 μg/ml). B/96E(37) and B/SRT were the most cytotoxic preparations, whereas the lowest toxicity was observed for B/W(37). B/96E(37) were shown to be active against Lewis lung carcinoma (LL/2) [IC(50) =25.06 μg/ml], cervical carcinoma (KB) [IC(50) =35.69 μg/ml] and colon adenocarcinoma (SW707) [IC(50) =49.06 μg/ml]. B/SRT was especially effective in inhibiting proliferation of cervical carcinoma (KB) [IC(50) =23.57 μg/ml], breast carcinoma (MCF-7) [IC(50) =29.86 μg/ml] and lung carcinoma (A-549) [IC(50) =40.03 μg/ml]. Further animal studies on mice bearing Lewis lung carcinoma showed significant inhibition of tumor growth by B/W(37) administered for 21 days at daily doses of 5 and 0.5 mg (p=0.0009). There were no significant changes in the cell cycles of tumor cells with the exception of cell decrease at the G₂/M phase after the administration of B/96E(37) at a daily dose of 0.5 mg and the G(1)/G(0) cells cycle arrest demonstrated after the B/SRT therapy at a daily-dose of 0.05 mg. All tested preparations were non-toxic and well tolerated.

Antitumoral and antioxidant effects of a hydroalcoholic extract of cat's claw (Uncaria tomentosa) (Willd. Ex Roem. & Schult) in an in vivo carcinosarcoma model

AIM OF THE STUDY

The present work intended to study the antitumoral and antioxidant effects of Uncaria tomentosa (UT) hydroalcoholic extract in the Walker-256 cancer model.

METHODS AND MATERIALS

Walker-256 cells were subcutaneously inoculated in the pelvic limb of male Wistar rats. Daily gavage with UT extract (10, 50 or 100 mg kg(-1), Groups UT) or saline solution (Control, Group C) was subsequently initiated, until 14 days afterwards. For some parameters, a group of healthy rats (Baseline, Group B) was added. At the end of treatment the following parameters were evaluated: (a) tumor volume and mass; (b) plasmatic concentration of urea, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and lactate dehydrogenase (LDH); (c) hepatic and tumoral activity of catalase (CAT) and superoxide dismutase (SOD), as well as the rate of lipid peroxidation (LPO) and gluthatione (GSH); and (d) hepatic glutathione-S-transferase (GST) activity. The reactivity of UT extract with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was assessed in parallel.

RESULTS

UT hydroalcoholic extract successfully reduced the tumor growth. In addition, treatment with UT reduced the activity of AST, which had been increased as a result of tumor inoculation, thus attempting to return it to normal levels. UT did not reverse the increase of LDH and GGT plasma levels, although all doses were remarkably effective in reducing urea plasma levels. An important in vitro free radical-scavenging activity was detected at various concentrations of UT extract (1-300 microg mL(-1)). Treatment also resulted in increased CAT activity in liver, while decreasing it in tumor tissue. SOD activity was reduced in liver as well as in tumor, compared to Group C. No statistical significance concerning ALT, GST, LPO or GSH were observed.

CONCLUSIONS

This data represent an in vivo demonstration of both antitumoral and antioxidant effects of UT hydroalcoholic extract. The antineoplastic activity may result, partially at least, from the ability of UT to regulate redox and metabolism homeostasis.

Phenolic compounds, antioxidant activity and in vitro inhibitory potential against key enzymes relevant for hyperglycemia and hypertension of commonly used medicinal plants, herbs and spices in Latin America

Traditionally used medicinal plants, herbs and spices in Latin America were investigated to determine their phenolic profiles, antioxidant activity and in vitro inhibitory potential against key enzymes relevant for hyperglycemia and hypertension. High phenolic and antioxidant activity-containing medicinal plants and spices such as Chancapiedra (Phyllantus niruri L.), Zarzaparrilla (Smilax officinalis), Yerba Mate (Ilex paraguayensis St-Hil), and Huacatay (Tagetes minuta) had the highest anti-hyperglycemia relevant in vitro alpha-glucosidase inhibitory activities with no effect on alpha-amylase. Molle (Schinus molle), Maca (Lepidium meyenii Walp), Caigua (Cyclanthera pedata) and ginger (Zingiber officinale) inhibited significantly the hypertension relevant angiotensin I-converting enzyme (ACE). All evaluated pepper (Capsicum) genus exhibited both anti-hyperglycemia and anti-hypertension potential. Major phenolic compounds in Matico (Piper angustifolium R.), Guascas (Galinsoga parviflora) and Huacatay were chlorogenic acid and hydroxycinnamic acid derivatives. Therefore, specific medicinal plants, herbs and spices from Latin America have potential for hyperglycemia and hypertension prevention associated with Type 2 diabetes.