Ethyl Acetate Fraction of Harpagophytum procumbens Prevents Oxidative Stress In Vitro and Amphetamine-Induced Alterations in Mice Behavior.

Microglial activation has been associated to the physiopathology of neurodegenerative diseases, such as schizophrenia, and can occur during inflammation and oxidative stress. Pharmacological treatment is associated with severe side effects, and studies for use of plant extracts may offer alternatives with lower toxicity. Harpagophytum procumbens (HP) is a plant known for its anti-inflammatory properties. In the present study, we characterized the ethyl acetate fraction of HP (EAF HP) by ESI-ToF-MS and investigated the effects EAF HP in a lipopolysaccharide (LPS) induced inflammation model on microglial cells (BV-2 lineage). MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), DCFH-DA (2',7'-dichlorofluorescein diacetate) and cell cycle flow cytometer analysis were performed. In vivo was investigated the amphetamine-induced psychosis model through behavioral (locomotor and exploratory activities, stereotypies and working memory) and biochemical (DCFH-DA oxidation and protein thiols) parameters in cortex and striatum of mice. EAF HP reduced activation and proliferation of microglial cells in 48 h (300 µg/mL) and in 72 h after treatments (50-500 µg/mL). Reactive oxygen species levels were lower at the concentration of 100 µg/mL EAF HP. We detected a modulatory effect on the cell cycle, with reduction of cells in S and G2/M phases. In mice, the pre-treatment with EAF HP, for 7 days, protected against positive and cognitive symptoms, as well as stereotypies induced by amphetamine. No oxidative stress was observed in this amphetamine-induced model of psychosis. Such findings suggest that EAF HP can modulate the dopaminergic neurotransmission and be a promising adjuvant in the treatment of locomotor alterations, cognitive deficits, and neuropsychiatric disorders.

The Fight against Infection and Pain: Devil's Claw (Harpagophytum procumbens) a Rich Source of Anti-Inflammatory Activity: 2011-2022.

Harpagophytum procumbens subsp. procumbens (Burch.) DC. ex Meisn. (Sesame seed Family-Pedaliaceae) is a popular medicinal plant known as Devil's claw. It is predominantly distributed widely over southern Africa. Its impressive reputation is embedded in its traditional uses as an indigenous herbal plant for the treatment of menstrual problems, bitter tonic, inflammation febrifuge, syphilis or even loss of appetite. A number of bioactive compounds such as terpenoids, iridoid glycosides, glycosides, and acetylated phenolic compounds have been isolated. Harpagoside and harpagide, iridoid glycosides bioactive compounds have been reported in countless phytochemical studies as potential anti-inflammatory agents as well as pain relievers. In-depth studies have associated chronic inflammation with various diseases, such as Alzheimer's disease, obesity, rheumatoid arthritis, type 2 diabetes, cancer, and cardiovascular and pulmonary diseases. In addition, 60% of chronic disorder fatalities are due to chronic inflammatory diseases worldwide. Inflammation and pain-related disorders have attracted significant attention as leading causes of global health challenges. Articles published from 2011 to the present were obtained and reviewed in-depth to determine valuable data findings as well as knowledge gaps. Various globally recognized scientific search engines/databases including Scopus, PubMed, Google Scholar, Web of Science, and ScienceDirect were utilized to collect information and deliver evidence. Based on the literature results, there was a dramatic decrease in the number of studies conducted on the anti-inflammatory and analgesic activity of Devil's claw, thereby presenting a potential research gap. It is also evident that currently in vivo clinical studies are needed to validate the prior massive in vitro studies, therefore delivering an ideal anti-inflammatory and analgesic agent in the form of H. procumbens products.

A sport cream (Harpago-Boswellia-ginger-escin) for localized neck/shoulder pain.

BACKGROUND: Neck/shoulder, sudden pain, or muscular pain (not associated to structural or bone/joints components), due to fascial or muscular strain is common in active subjects, in non-professional athletes and sports performers. The aim of this supplement registry was the evaluation of a cream based on natural, active ingredients for topical application in supporting the improvement of pain and improving head/neck mobility, possibly minimizing the use of systemic drugs. METHODS: The cream includes standardized active ingredients of natural origin as an extract of Harpagophytum procumbes, an extract from Boswellia serrata, a CO2 extract of ginger and escin. Subjects were divided into three groups, all using the standard management (SM) in combination with the Sport Cream or in addition to Flector (diclofenac) patch. RESULTS: The groups were comparable and homogeneous at the baseline. No side effects or skin tolerability issues were observed with the Sport Cream nor with the SM or diclofenac patches. Subjects receiving sport cream + SM reported a significant improvement in pain, stiffness, altered mobility and altered working capacity, with a reduced need for rescue medication (diclofenac) compared to subjects in the other two groups. CONCLUSIONS: Finally, subjects receiving sport cream + SM reported a more remarkable decrease in skin temperature in the affected area associated to an improvement in clinical symptoms.

Harpagophytum procumbens Extract Ameliorates Allodynia and Modulates Oxidative and Antioxidant Stress Pathways in a Rat Model of Spinal Cord Injury.

Spinal cord injury (SCI) is a deliberating disorder with impairments in locomotor deficits and incapacitating sensory abnormalities. Harpagophytum procumbens (Hp) is a botanical widely used for treating inflammation and pain related to various inflammatory and musculoskeletal conditions. Using a modified rodent contusion model of SCI, we explored the effects of this botanical on locomotor function and responses to mechanical stimuli, and examined possible neurochemical changes associated with SCI-induced allodynia. Following spinal cord contusion at T10 level, Hp (300 mg/kg, p.o.) or vehicle (water) was administered daily starting 24 h post-surgery, and behavioral measurements made every-other day until sacrifice (Day 21). Hp treatment markedly ameliorated the contusion-induced decrease in locomotor function and increased sensitivity to mechanical stimuli. Determination of Iba1 expression in spinal cord tissues indicated microglial infiltration starting 3 days post-injury. SCI results in increased levels of 4-hydroxynonenal, an oxidative stress product and proalgesic, which was diminished at 7 days by treatment with Hp. SCI also enhanced antioxidant heme oxygenase-1 (HO-1) expression. Concurrent studies of cultured murine BV-2 microglial cells revealed that Hp suppressed oxidative/nitrosative stress and inflammatory responses, including production of nitric oxide and reactive oxygen species, phosphorylation of cytosolic phospholipases A2, and upregulation of the antioxidative stress pathway involving the nuclear factor erythroid 2-related factor 2 and HO-1. These results support the use of Hp for management of allodynia by providing resilience against the neuroinflammation and pain associated with SCI and other neuropathological conditions.

Devil's claw (Harpagophytum procumbens) and chronic inflammatory diseases: A concise overview on preclinical and clinical data.

Devil's Claw is a traditional medicine that has been long used a wide range of health conditions, including indigestion, fever, allergic reactions, and rheumatism. The main compounds are iridoid glycosides, including harpagoside, harpagide, and procumbide. However, harpagoside is the most responsible for therapeutic activity, and its content is used as reference standard. Here, we analyzed and summarized preclinical and clinical studies focusing on therapeutic efficacy of devil's claw preparations in pathological conditions in which inflammation plays a key causative role.

Quality Assessment of Commercial Spagyric Tinctures of Harpagophytum procumbens and Their Antioxidant Properties.

Preparations from the dried tubers of Harpagophytum procumbens (Burch.) DC ex Meisn, commonly known as devil's claw, are mainly used in modern medicine to relieve joint pain and inflammation in patients suffering from rheumatic and arthritic disorders. This paper describes for the first time the chemical profile of a commercial spagyric tincture (named 019) prepared from the roots of the plant. For comparison purposes, a commercial not-spagyric devil's claw tincture (NST) was also analyzed. Chemical investigation of the content of specialized metabolites in the three samples indicated that harpagoside was the main compound, followed by the two isomers acteoside and isoacteoside. Compositional consistence over time was obtained by the chemical fingerprinting of another spagyric tincture (named 014) from the same producer that was already expired according to the recommendation on the label of the product. The two spagyric preparations did not show significant compositional differences as revealed by HPLC and MS analyses, except for a decrease in harpagide content in the expired 014 tincture. Moreover, their antioxidant capacities as assessed by 2,2'-di-phenyl-1-picrylhydrazyl (DPPH) and 2.2'-azin-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods resulted in very similar IC50 values. The expired 014 tincture showed instead a lower IC50 value compared to the 019 and NST tinctures with the ferric reducing antioxidant potential (FRAP) assay, indicating a higher ferric-reducing antioxidant ability. Overall, these results indicated that the two preparations could generally maintain good stability and biological activity at least for the four years from the production to the expiration date.

The Anti-Inflammatory Effects of Shinbaro3 Is Mediated by Downregulation of the TLR4 Signalling Pathway in LPS-Stimulated RAW 264.7 Macrophages.

Shinbaro3, a formulation derived from the hydrolysed roots of Harpagophytum procumbens var. sublobatum (Engl.) Stapf, has been clinically used in the pharamacopuncture treatment of arthritis in Korea. In the present study, Shinbaro3 inhibited NO generation in LPS-induced RAW 264.7 cells in a dose-dependent manner. Shinbaro3 also downregulated the mRNA and protein expression of inflammatory mediators in a dose-dependent manner. Three mechanisms explaining the effects of Shinbaro3 in RAW 264.7 cells were identified as follows: (1) inhibition of the extracellular signal-regulated kinase 1 and 2 (ERK1/2), stress-activated protein kinase (SAPK)/c-Jun N-terminal protein kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) pathways; (2) suppression of IκB kinase-α/ß (IKK-α/ß) phosphorylation and nuclear factor-kappa B (NF-κB) subunits in the NF-κB pathway, which are involved in MyD88-dependent signalling; and (3) downregulation of IFN-ß mRNA expression via inhibition of interferon regulatory factor 3 (IRF3) and Janus-activated kinase 1 (JAK1)/signal transducer and activator of transcription 1 (STAT1) phosphorylation, which is involved in TRIF-dependent signalling. Shinbaro3 exerted anti-inflammatory effects in LPS-stimulated RAW 264.7 macrophage cells through modulation of the TLR4/MyD88 pathways, suggesting that Shinbaro3 is a novel anti-inflammatory therapeutic candidate in the field of pharmacopuncture.

Use of Innovative (Micro)Extraction Techniques to Characterise Harpagophytum procumbens Root and its Commercial Food Supplements.

INTRODUCTION: For the determination of harpagoside and the wide phenolic pattern in Harpagophytum procumbens root and its commercial food supplements, dispersive liquid-liquid microextraction (DLLME), ultrasound-assisted DLLME (UA-DLLME), and sugaring-out liquid-liquid extraction (SULLE) were tested and compared. OBJECTIVES: In order to optimise the extraction efficiency, DLLME and UA-DLLME were performed in different solvents (water and aqueous solutions of glucose, ß-cyclodextrin, (2-hydroxypropyl)-ß-cyclodextrin, sodium chloride, natural deep eutectic solvent, and ionic liquid). MATERIAL AND METHODS: The plant material was ground and sieved to obtain a uniform granulometry before extraction. Commercial food supplements, containing H. procumbens are commercially available in Italy. RESULTS: The most effective sodium chloride-aided-DLLME was then optimised and applied for analyses followed by HPLC-PDA. For comparison, microwave-assisted extraction was performed using the same solvents and the best results were obtained using 1% of ß-cyclodextrin or 15% of sodium chloride. CONCLUSION: All commercial samples respected the European Pharmacopoeia monograph for this plant material, showing a harpagoside content ≥ 1.2%. Copyright © 2017 John Wiley & Sons, Ltd.

Oral herbal medicines marketed in Brazil for the treatment of osteoarthritis: A systematic review and meta-analysis.

Herbal medications are commonly used to manage symptoms associated with osteoarthritis (OA). This systematic review evaluated the effectiveness and safety of oral medications used in Brazil for the treatment of OA. Randomized clinical trials involving adults with OA treated by a herbal medicine or a control group were eligible. The primary outcomes measured were pain, physical function, swelling, stiffness and quality of life; and the secondary outcomes were adverse events, activity limitations and treatment satisfaction. Sixteen studies were included (n = 1,741 patients) in the systematic review and nine studies in the meta-analysis, representing 6 of the 13 herbal medicines studied: Boswellia serrata (n = 2), Curcuma longa (n = 3), Harpagophytum procumbens (n = 1), Salix daphnoides (n = 3), Uncaria guianensis (n = 2) and Zingiber officinale (n = 5). B. serrata was more effective than both placebo and valdecoxib for improvement of pain and physical function. No difference was observed for H. procumbens, C. longa and U. guianensis compared with control. Z. officinale showed improvement of pain over placebo. The evidence was insufficient to support the effective and safe use of these herbal medicines, because the quality of evidence of studies was low. This study guides managers of the Brazilian public health system and prescribers in decision-making regarding the use of these herbal medicines for OA. Copyright © 2017 John Wiley & Sons, Ltd.

A Rosa canina - Urtica dioica - Harpagophytum procumbens/zeyheri Combination Significantly Reduces Gonarthritis Symptoms in a Randomized, Placebo-Controlled Double-Blind Study.

The special formulation MA212 (Rosaxan) is composed of rosehip (Rosa canina L.) puree/juice concentrate, nettle (Urtica dioica L.) leaf extract, and devil's claw (Harpagophytum procumbens DC. ex Meisn. or Harpagophytum zeyheri Decne.) root extract and also supplies vitamin D. It is a food for special medical purposes ([EU] No 609/2013) for the dietary management of pain in patients with gonarthritis.This 12-week randomized, placebo-controlled double-blind parallel-design study aimed to investigate the efficacy and safety of MA212 versus placebo in patients with gonarthritis.A 3D-HPLC-fingerprint (3-dimensional high pressure liquid chromatography fingerprint) of MA212 demonstrated the presence of its herbal ingredients. Ninety-two randomized patients consumed 40 mL of MA212 (n = 46) or placebo (n = 44) daily. The Western Ontario and McMaster Universities Arthritis Index (WOMAC), quality-of-life scores at 0, 6, and 12 weeks, and analgesic consumption were documented. Statistically, the initial WOMAC subscores/scores did not differ between groups. During the study, their means significantly improved in both groups. The mean pre-post change of the WOMAC pain score (primary endpoint) was 29.87 in the MA212 group and 10.23 in the placebo group. The group difference demonstrated a significant superiority in favor of MA212 (pU < 0.001; pt < 0.001). Group comparisons of all WOMAC subscores/scores at 6 and 12 weeks reached same significances. Compared to placebo, both physical and mental quality of life significantly improved with MA212. There was a trend towards reduced analgesics consumption with MA212, compared to placebo. In the final efficacy evaluation, physicians (pChi < 0.001) and patients (pChi < 0.001) rated MA212 superior to placebo. MA212 was well tolerated.This study demonstrates excellent efficacy for MA212 in gonarthritis patients.

Protective Effects Induced by Microwave-Assisted Aqueous Harpagophytum Extract on Rat Cortex Synaptosomes Challenged with Amyloid ß-Peptide.

Harpagophytum procumbens is a plant species that displays anti-inflammatory properties in multiple tissues. The iridoid glycosides arpagoside, harpagide, and procumbide appear to be the most therapeutically important constituents. In addition, harpagoside treatment exerted neuroprotective effects both in vitro and in vivo. Considering these findings, the aim of the present work is to explore the possible protective role of the previously described microwave-assisted aqueous extract of H. procumbens on rat hypothalamic (Hypo-E22) cells, and in rat cortex challenged with amyloid ß-peptide (1-40). In this context, we assayed the protective effects induced by H. procumbens by measuring the levels of malondialdehyde, 3-hydroxykynurenine (3-HK), brain-derived neurotrophic factor, and tumor necrosis factor-α, 3-HK. Finally, we evaluated the effects of H. procumbens treatment on cortex levels of dopamine, norepinephrine, and serotonin. H. procumbens extract was well tolerated by Hypo-E22 cells and upregulated brain-derived neurotrophic factor gene expression but down-regulated tumor necrosis factor-α gene expression. In addition, the extract reduced amyloid ß-peptide stimulation of malondialdehyde and 3-HK and blunted the decrease of dopamine, norepinephrine, and serotonin, in the cortex. In this context, our work supports further studies for the evaluation and confirmation of Harpagophytum in the management of the clinical symptoms related to Alzheimer's disease. Copyright © 2017 John Wiley & Sons, Ltd.

Optimization of Aqueous Extraction and Biological Activity of Harpagophytum procumbens Root on Ex Vivo Rat Colon Inflammatory Model.

Harpagophytum procumbens has a long story of use for the treatment of inflammatory diseases. Considering both the antiinflammatory effects of H. procumbens in multiple tissues and the stability of harpagoside in artificial intestinal fluid, the aim of the present study was to explore the possible protective role of a microwave-assisted aqueous Harpagophytum extract (1-1000 µg/mL) on mouse myoblast C2C12 and human colorectal adenocarcinoma HCT116 cell lines, and isolated rat colon specimens challenged with lipopolysaccharide (LPS), a validated ex vivo model of acute ulcerative colitis. In this context, we evaluated the effects on C2C12 and HCT116 viability, and on LPS-induced production of serotonin (5-HT), tumor necrosis factor (TNF)-α, prostaglandin (PG)E2 and 8-iso-prostaglandin (8-iso-PG)F2α . Harpagophytum extract was well tolerated by C2C12 cells, while reduced HCT116 colon cancer cell viability. On the other hand, Harpagophytum extract reduced H2 O2 -induced (1 mM) reactive oxygen species (ROS) production, in both cell lines, and inhibited LPS-induced colon production of PGE2 , 8-iso-PGF2α , 5-HT and TNFα. Concluding, we demonstrated the efficacy of a microwave-assisted Harpagophytum aqueous extract in modulating the inflammatory, oxidative stress and immune response in an experimental model of inflammatory bowel diseases (IBD), thus suggesting a rational use of Harpagophytum in the management and prevention of ulcerative colitis in humans. Copyright © 2017 John Wiley & Sons, Ltd.

Risk Assessment via Metabolism and Cell Growth Inhibition in a HepG2/C3A Cell Line Upon Treatment with Arpadol and its Active Component Harpagoside.

Harpagophytum procumbens (Hp) has been used as antiinflammatory and analgesic agent for the treatment of rheumatic diseases. The principal active component of Hp is harpagoside (HA). We tested the toxicity of this new therapeutic agent in a hepatic cell line (HepG2/C3A). Hp was found to be cytotoxic, and HA was found to decrease the number of cells in S phase, increase the number of cells in G2/M phase and induce apoptosis. Neither Hp nor HA was genotoxic. The expression of CDK6 and CTP3A4 was reduced by Hp, and both HA and Hp caused a significant reduction of CYP1A2 and CYP3A4 expression. It is possible that the cytotoxicity caused by HA and Hp does not involve transcriptional regulation of the cyclins and CDKs tested but is instead related to the inhibition of metabolism. This is evidenced by the results of an MTT assay and changes in the expression of genes related to drug metabolism, leading to cell death. Indeed, the cells exhibited decreased proliferation upon exposure to Hp and HA. The data show that treatment with either Hp or HA can be cytotoxic, and this should be taken into consideration when balancing the risks and benefits of treatments for rheumatic diseases. Copyright © 2016 John Wiley & Sons, Ltd.

Alteration of Neutrophil Reactive Oxygen Species Production by Extracts of Devil's Claw (Harpagophytum).

Harpagophytum, Devil's Claw, is a genus of tuberiferous xerophytic plants native to southern Africa. Some of the taxa are appreciated for their medicinal effects and have been traditionally used to relieve symptoms of inflammation. The objectives of this pilot study were to investigate the antioxidant capacity and the content of total phenols, verbascoside, isoverbascoside, and selected iridoids, as well as to investigate the capacity of various Harpagophytum taxa in suppressing respiratory burst in terms of reactive oxygen species produced by human neutrophils challenged with phorbol myristate acetate (PMA), opsonised Staphylococcus aureus, and Fusobacterium nucleatum. Harpagophytum plants were classified into different taxa according to morphology, and DNA analysis was used to confirm the classification. A putative new variety of H. procumbens showed the highest degree of antioxidative capacity. Using PMA, three Harpagophytum taxa showed anti-inflammatory effects with regard to the PBS control. A putative hybrid between H. procumbens and H. zeyheri in contrast showed proinflammatory effect on the response of neutrophils to F. nucleatum in comparison with treatment with vehicle control. Harpagophytum taxa were biochemically very variable and the response in suppressing respiratory burst differed. Further studies with larger number of subjects are needed to corroborate anti-inflammatory effects of different taxa of Harpagophytum.

The influence of harpagoside and harpagide on TNFα-secretion and cell adhesion molecule mRNA-expression in IFNγ/LPS-stimulated THP-1 cells.

Inflammation does not only lead to pain and functio laesa in the affected tissue but is also implicated in the onset and progression of cardiovascular diseases and cancer. Many medicinal plants show anti-inflammatory properties yet plant-constituents and their effect on molecular pathways involved in the attenuation of inflammation as well as cell migration are only poorly understood. Harpagophytum procumbens DC. ex MEISN. is a potent plant used as an immune modulator in traditional herbal medicine. Aim of this study was to investigate the influence of harpagoside and harpagide on TNFα-secretion in undifferentiated and differentiated THP-1 cells under inflammatory conditions as well as their implication in cellular migration into inflamed tissue. We found that both iridoids decrease TNFα-secretion in PMA-differentiated THP-1 cells whereas undifferentiated cells were poorly affected. Yet, in undifferentiated cells harpagoside and harpagide induced mRNA-expression of certain proteins involved in leukocyte transmigration. Especially TNFα and ICAM-1 mRNA-expression was positively affected after 3h and expression could be maintained on high levels even after 48h. L-selectin and PSGL-1 were strongly induced after 48h of stimulation. This ambiguous effect of harpagoside and harpagide highlights their immune modulatory function by facilitating cell migration into the inflamed tissue, whereby in consequence the anti-inflammatory activity of the resident macrophages was also found to be promoted.

Harpagophytum Procumbens Ethyl Acetate Fraction Reduces Fluphenazine-Induced Vacuous Chewing Movements and Oxidative Stress in Rat Brain.

Long-term treatment with fluphenazine is associated with manifestation of extrapyramidal side effects, such as tardive dyskinesia. The molecular mechanisms related to the pathophysiology of TD remain unclear, and several hypotheses, including a role for oxidative stress, have been proposed. Harpagophytum procumbens is an herbal medicine used mainly due to anti-inflammatory effects, but it also exhibits antioxidant effects. We investigated the effect of ethyl acetate fraction of H. procumbens (EAF HP) in fluphenazine-induced orofacial dyskinesia by evaluating behavioral parameters at different times (vacuous chewing movements (VCM's) and locomotor and exploratory activity), biochemical serological analyses, and biochemical markers of oxidative stress of the liver, kidney, cortex, and striatum. Chronic administration of fluphenazine (25 mg/kg, intramuscular (i.m) significantly increased the VCMs at all analyzed times (2, 7, 14, and 21 days), and this was inhibited by EAF HP (especially at a dose of 30 mg/kg). Fluphenazine decreased locomotion and exploratory activity, and EAF HP did not improve this decrease. Fluphenazine induced oxidative damage, as identified by changes in catalase activity and ROS levels in the cortex and striatum, which was reduced by EAF HP, especially in the striatum. In the cortex, EAF HP was protective against fluphenazine-induced changes in catalase activity but not against the increase in ROS level. Furthermore, EAF HP was shown to be safe, since affected serum biochemical parameters or parameters of oxidative stress in the liver and kidney. These findings suggest that the H. procumbens is a promising therapeutic agent for the treatment of involuntary oral movements.

Harpagoside Content in Devil's Claw Extracts.

Devil's claw is a common ingredient in nutraceutical products for the treatment of inflammation due to arthritis. The secondary root extract of Harpagophymn piocumbens contains bioactive iridoid glycosides known as harpagosides. Recent scrutiny of the nutraceutical industry claims that products listing devil's claw on their labels should refer only to H. procumbens, while the closely related, and less expensive, H. zeyheri is not to be classified as devil's claw. .This assertion is in contrast to botanists who claim that either species of Harpagophytum can be generically referred to as devil's claw. The current research aimed to determine the chemical composition of extracts from H. procumbens and H. zeyheri, with the intent to identify whether the bioactive harpagosides were similarly present between species, and how their presence resembled or deviated from commercially available H. procumbens extracts commonly used in -nutraceutical products. A microwave extraction followed by high performance liquid chromatography analysis of root samples from botanical specimens of H. procimbens and H. zeyheri identified similar quantities of harpagoside, regardless of species. The chemical composition between root extracts for each.species was found to contain varying quantities of non-harpagoside constituents, however their harpagoside content was comparable. These findings are intended to inform policymakers, nutraceutical manufacturers, and the general public of the distinction between myth and reality regarding devil's claw supplements.

Harpagophytum procumbens extract potentiates morphine antinociception in neuropathic rats.

The association of opioids and non-steroidal anti-inflammatory drugs, to enhance pain relief and reduce the development of side effects, has been demonstrated. Given many reports concerning the antinociceptive and anti-inflammatory effects of Harpagophytum procumbens extracts, the aim of our study was to investigate the advantage of a co-administration of a subanalgesic dose of morphine preceded by a low dose of H. procumbens to verify this therapeutically useful association in a neuropathic pain model. Time course, registered with the association of the natural extract, at a dose that does not induce an antinociceptive effect, followed by a subanalgesic dose of morphine showed a well-defined antiallodynic and antihyperalgesic effect, suggesting a synergism as a result of the two-drug association. H. procumbens cooperates synergistically with morphine in resolving hyperalgesia and allodynia, two typical symptoms of neuropathic pain. The results support the strategy of using an adjuvant drug to improve opioid analgesic efficacy.

A new iridoid diglucoside from Harpagophytum procumbens.

A new iridoid diglucoside has been isolated from an aqueous extract of Harpagophytum procumbens secondary roots, together with six known compounds. Its structure has been assigned as 6'-O-glucopyranosyl-8-O-trans-coumaroylharpagide by spectroscopic means.

Involvement of the Heme-Oxygenase Pathway in the Antiallodynic and Antihyperalgesic Activity of Harpagophytum procumbens in Rats.

Harpagophytum procumbens (H. procumbens), also known as Devil's Claw, has been used to treat a wide range of pathological conditions, including pain, arthritis and inflammation. Inflammatory mediators, released at the site of injury, can sensitize nociceptive terminals and are responsible for allodynia and hyperalgesia. Carbon monoxide (CO), produced in a reaction catalyzed by the enzyme heme oxygenase (HO), may play a role in nociceptive processing and has also been recognized to act as a neurotransmitter or neuromodulator in the nervous system. This study was designed to investigate whether the HO/CO pathway is involved in the analgesic response of H. procumbens in carrageenan-induced hyperalgesia in rats. Mechanical allodynia and thermal hyperalgesia were evaluated by using von Frey filaments and the plantar test, respectively. The results of our experiments showed that pretreatment with the HO inhibitor ZnPP IX significantly decreased the antihyperalgesic effect produced by H. procumbens (800 mg/kg, i.p.) in carrageenan-injected rats. Consistently, the pretreatment with hemin, a HO-1 substrate, or CORM-3, a CO releasing molecule, before a low dose of H. procumbens (300 mg/kg, i.p.) induced a clear antiallodynic response in carrageenan injected rats. These results suggest the involvement of HO-1/CO system in the antiallodynic and antihyperalgesic effect of H. procumbens in carrageenan-induced inflammatory pain.