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Machado Kayser J, Petry F, Alijar Souza M, Santin Zanatta Schindler M, Vidor Morgan L, Zimmermann Prado Rodrigues G, Mazon SC, Silva Aguiar GP, Galdino da Rocha Pitta M, da Rocha Pitta I, Leal Xavier L, Girardi Müller L, Gehlen G, Heemann Betti A. Antidepressant effect of PT-31, an α₂-adrenoceptor agonist, on lipopolysaccharide-induced depressive-like behavior in mice. Behav Pharmacol 2024; 35:338-350. [PMID: 39051900 DOI: 10.1097/fbp.0000000000000785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Increasing evidence indicates that neuroinflammation, oxidative stress, and neurotrophic factors play a key role in the pathophysiology of major depressive disorder (MDD). In addition, the attenuation of inflammatory response has been considered a putative mechanism for MDD treatment. PT-31 is an imidazolidine derivative and a putative α₂-adrenoceptor agonist that has previously demonstrated antinociceptive activity. The present study aimed to investigate the effect of PT-31 on depressive-like behavior and lipopolysaccharide-induced neurochemical changes. To this end, mice received intraperitoneally saline or lipopolysaccharide (600 µg/kg), and 5 h postinjection animals were orally treated with saline, PT-31 (3, 10, and 30 mg/kg), or fluoxetine (30 mg/kg). Mice were subjected to the open field test (OFT) 6 and 24 h after lipopolysaccharide administration and to the tail suspension test (TST) 24 h postlipopolysaccharide. Subsequently, animals were euthanized, and brains were dissected for neurochemical analyses. The administration of lipopolysaccharide-induced sickness- and depressive-like behaviors, besides promoting an increase in myeloperoxidase activity and a reduction in brain-derived neurotrophic factor (BDNF) levels. Noteworthy, PT-31 3 mg/kg attenuated lipopolysaccharide-induced decreased locomotor activity 6 h after lipopolysaccharide in the OFT. All tested doses of PT-31 significantly reduced the immobility time of animals in the TST and attenuated lipopolysaccharide-induced increased myeloperoxidase activity in the cortex of mice. Our results demonstrate that PT-31 ameliorates behavioral changes promoted by lipopolysaccharide in OFT and TST, which is possibly mediated by attenuation of the inflammatory response.
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Affiliation(s)
- Juliana Machado Kayser
- Postgraduate Program in Toxicology and Analytical Toxicology, Health Sciences Institute, Feevale University, Novo Hamburgo
| | - Fernanda Petry
- Molecular Genetics and Ecotoxicology Laboratory, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
- Postgraduate Program in Environmental Sciences, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
| | - Maryelen Alijar Souza
- Postgraduate Program in Environmental Sciences, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
| | - Monica Santin Zanatta Schindler
- Postgraduate Program in Environmental Sciences, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
| | - Letícia Vidor Morgan
- Pharmacy Course, Health Sciences Area, Community University of Chapecó Region (Unochapecó), Chapecó
| | | | - Samara Cristina Mazon
- Molecular Genetics and Ecotoxicology Laboratory, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
- Postgraduate Program in Environmental Sciences, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
| | - Gean Pablo Silva Aguiar
- Molecular Genetics and Ecotoxicology Laboratory, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
- Postgraduate Program in Environmental Sciences, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
| | - Marina Galdino da Rocha Pitta
- Nucleus of Research in Therapeutic Innovation Suely Galdino (NUPIT SG), Biosciences Center, Federal University of Pernambuco, Recife
| | - Ivan da Rocha Pitta
- Nucleus of Research in Therapeutic Innovation Suely Galdino (NUPIT SG), Biosciences Center, Federal University of Pernambuco, Recife
| | - Léder Leal Xavier
- Postgraduate Program in Cellular and Molecular Biology, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, Brazil
| | - Liz Girardi Müller
- Molecular Genetics and Ecotoxicology Laboratory, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
- Postgraduate Program in Environmental Sciences, Sciences and Environmental Area, Community University of Chapecó Region (Unochapecó)
| | - Günther Gehlen
- Postgraduate Program in Toxicology and Analytical Toxicology, Health Sciences Institute, Feevale University, Novo Hamburgo
- Postgraduate Program in Environmental Quality, Health Sciences Institute, Feevale University, Novo Hamburgo
| | - Andresa Heemann Betti
- Postgraduate Program in Toxicology and Analytical Toxicology, Health Sciences Institute, Feevale University, Novo Hamburgo
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Kocot-Kępska M, Pawlik K, Ciapała K, Makuch W, Zajączkowska R, Dobrogowski J, Przeklasa-Muszyńska A, Mika J. Phenytoin Decreases Pain-like Behaviors and Improves Opioid Analgesia in a Rat Model of Neuropathic Pain. Brain Sci 2023; 13:858. [PMID: 37371338 DOI: 10.3390/brainsci13060858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/18/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
Neuropathic pain remains a clinical challenge due to its complex and not yet fully understood pathomechanism, which result in limited analgesic effectiveness of the management offered, particularly for patients with acute, refractory neuropathic pain states. In addition to the introduction of several modern therapeutic approaches, such as neuromodulation or novel anti-neuropathic drugs, significant efforts have been made in the repurposing of well-known substances such as phenytoin. Although its main mechanism of action occurs at sodium channels in excitable and non-excitable cells and is well documented, how the drug affects the disturbed neuropathic interactions at the spinal cord level and how it influences morphine-induced analgesia have not been clarified, both being crucial from a clinical perspective. We demonstrated that single and repeated systemic administrations of phenytoin decreased tactile and thermal hypersensitivity in an animal model of neuropathic pain. Importantly, we observed an increase in the antinociceptive effect on thermal stimuli with repeated administrations of phenytoin. This is the first study to report that phenytoin improves morphine-induced antinociceptive effects and influences microglia/macrophage activity at the spinal cord and dorsal root ganglion levels in a neuropathic pain model. Our findings support the hypothesis that phenytoin may represent an effective strategy for neuropathic pain management in clinical practice, particularly when combination with opioids is needed.
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Affiliation(s)
- Magdalena Kocot-Kępska
- Department of Pain Research and Treatment, Jagiellonian University Medical College, 31-501 Krakow, Poland
| | - Katarzyna Pawlik
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
| | - Katarzyna Ciapała
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
| | - Wioletta Makuch
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
| | - Renata Zajączkowska
- Department of Interdisciplinary Intensive Care, Jagiellonian University Medical College, 30-688 Krakow, Poland
| | - Jan Dobrogowski
- Department of Pain Research and Treatment, Jagiellonian University Medical College, 31-501 Krakow, Poland
| | - Anna Przeklasa-Muszyńska
- Department of Pain Research and Treatment, Jagiellonian University Medical College, 31-501 Krakow, Poland
| | - Joanna Mika
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
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Lin X, Tago K, Okazaki N, So T, Takahashi K, Mashino T, Tamura H, Funakoshi-Tago M. The indole-hydantoin derivative exhibits anti-inflammatory activity by preventing the transactivation of NF-κB through the inhibition of NF-κB p65 phosphorylation at Ser276. Int Immunopharmacol 2021; 100:108092. [PMID: 34474272 DOI: 10.1016/j.intimp.2021.108092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 08/18/2021] [Accepted: 08/22/2021] [Indexed: 01/17/2023]
Abstract
Indole- and hydantoin-based derivatives both exhibit anti-inflammatory activity, suggesting that the structures of indole and hydantoin are functional for this activity. In the present study, we synthesized two types of indole-hydantoin derivatives, IH-1 (5-(1H-indole-3-ylmethylene) imidazolidine-2,4-dione) and IH-2 (5-(1H-indole-3-ylmethyl) imidazolidine-2,4-dione) and examined their effects on LPS-induced inflammatory responses in murine macrophage-like RAW264.7 cells. LPS-induced inflammatory responses were not affected by indole, hydantoin, or IH-2. In contrast, IH-1 significantly inhibited the LPS-induced production of nitric oxide (NO) and secretion of CCL2 and CXCL1 by suppressing the mRNA expression of inducible NO synthase (iNOS), CCL2, and CXCL1. IH-1 markedly inhibited the LPS-induced activation of NF-κB without affecting the degradation of IκBα or nuclear translocation of NF-κB. IH-1 markedly attenuated the transcriptional activity of NF-κB by suppressing the LPS-induced phosphorylation of the NF-κB p65 subunit at Ser276. Furthermore, IH-1 prevented the LPS-induced interaction of NF-κB p65 subunit with a transcriptional coactivator, cAMP response element-binding protein (CBP). Collectively, these results revealed the potential of the novel indole-hydantoin derivative, IH-1 as an anti-inflammatory drug.
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Affiliation(s)
- Xin Lin
- Division of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan
| | - Kenji Tago
- Division of Structural Biochemistry, Department of Biochemistry, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi-ken 329-0498, Japan.
| | - Nozomi Okazaki
- Division of Bio-organic and Medicinal Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan
| | - Takanori So
- Division of Bio-organic and Medicinal Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan
| | - Kyoko Takahashi
- Division of Bio-organic and Medicinal Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan
| | - Tadahiko Mashino
- Division of Bio-organic and Medicinal Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan
| | - Hiroomi Tamura
- Division of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan
| | - Megumi Funakoshi-Tago
- Division of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan.
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Topical Treatments and Their Molecular/Cellular Mechanisms in Patients with Peripheral Neuropathic Pain-Narrative Review. Pharmaceutics 2021; 13:pharmaceutics13040450. [PMID: 33810493 PMCID: PMC8067282 DOI: 10.3390/pharmaceutics13040450] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/17/2021] [Accepted: 03/22/2021] [Indexed: 12/25/2022] Open
Abstract
Neuropathic pain in humans results from an injury or disease of the somatosensory nervous system at the peripheral or central level. Despite the considerable progress in pain management methods made to date, peripheral neuropathic pain significantly impacts patients' quality of life, as pharmacological and non-pharmacological methods often fail or induce side effects. Topical treatments are gaining popularity in the management of peripheral neuropathic pain, due to excellent safety profiles and preferences. Moreover, topical treatments applied locally may target the underlying mechanisms of peripheral sensitization and pain. Recent studies showed that peripheral sensitization results from interactions between neuronal and non-neuronal cells, with numerous signaling molecules and molecular/cellular targets involved. This narrative review discusses the molecular/cellular mechanisms of drugs available in topical formulations utilized in clinical practice and their effectiveness in clinical studies in patients with peripheral neuropathic pain. We searched PubMed for papers published from 1 January 1995 to 30 November 2020. The key search phrases for identifying potentially relevant articles were "topical AND pain", "topical AND neuropathic", "topical AND treatment", "topical AND mechanism", "peripheral neuropathic", and "mechanism". The result of our search was 23 randomized controlled trials (RCT), 9 open-label studies, 16 retrospective studies, 20 case (series) reports, 8 systematic reviews, 66 narrative reviews, and 140 experimental studies. The data from preclinical studies revealed that active compounds of topical treatments exert multiple mechanisms of action, directly or indirectly modulating ion channels, receptors, proteins, and enzymes expressed by neuronal and non-neuronal cells, and thus contributing to antinociception. However, which mechanisms and the extent to which the mechanisms contribute to pain relief observed in humans remain unclear. The evidence from RCTs and reviews supports 5% lidocaine patches, 8% capsaicin patches, and botulinum toxin A injections as effective treatments in patients with peripheral neuropathic pain. In turn, single RCTs support evidence of doxepin, funapide, diclofenac, baclofen, clonidine, loperamide, and cannabidiol in neuropathic pain states. Topical administration of phenytoin, ambroxol, and prazosin is supported by observational clinical studies. For topical amitriptyline, menthol, and gabapentin, evidence comes from case reports and case series. For topical ketamine and baclofen, data supporting their effectiveness are provided by both single RCTs and case series. The discussed data from clinical studies and observations support the usefulness of topical treatments in neuropathic pain management. This review may help clinicians in making decisions regarding whether and which topical treatment may be a beneficial option, particularly in frail patients not tolerating systemic pharmacotherapy.
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Wu XL, Liu L, Li YJ, Luo J, Gai DW, Lu TL, Mei QB. Synthesis, crystal structure, and antinociceptive effects of some new riluzole derivatives. Med Chem Res 2018. [DOI: 10.1007/s00044-018-2154-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Wadood A, Ghufran M, Hassan SF, Khan H, Azam SS, Rashid U. In silico identification of promiscuous scaffolds as potential inhibitors of 1-deoxy-d-xylulose 5-phosphate reductoisomerase for treatment of Falciparum malaria. PHARMACEUTICAL BIOLOGY 2017; 55:19-32. [PMID: 27650666 PMCID: PMC7011789 DOI: 10.1080/13880209.2016.1225778] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/12/2016] [Indexed: 05/20/2023]
Abstract
CONTEXT Malaria remains one of the prevalent infectious diseases worldwide. Plasmodium falciparum 1-deoxy-d-xylulose-5-phosphate reductoisomerase (PfDXR) plays a role in isoprenoid biosynthesis in the malaria parasite, making this parasite enzyme an attractive target for antimalarial drug design. Fosmidomycin is a promising DXR inhibitor, which showed safety as well as efficacy against Plasmodium falciparum malaria in clinical trials. However, due to its poor oral bioavailability and non-drug-like properties, the focus of medicinal chemists is to develop inhibitors with improved pharmacological properties. OBJECTIVE This study described the computational design of new and potent inhibitors for deoxyxylulose 5-phosphate reductoisomerase and the prediction of their pharmacokinetic and pharmacodynamic properties. MATERIAL AND METHODS A complex-based pharmacophore model was generated from the complex X-ray crystallographic structure of PfDXR using MOE (Molecular Operating Environment). Furthermore, MOE-Dock was used as docking software to predict the binding modes of hits and target enzyme. RESULTS Finally, 14 compounds were selected as new and potent inhibitors of PfDXR on the basis of pharmacophore mapping, docking score, binding energy and binding interactions with the active site residues of the target protein. The predicted pharmacokinetic properties showed improved permeability by efficiently crossing blood-brain barrier. While, in silico promiscuity binding data revealed that these hits also have the ability to bind with other P. falciparum drug targets. DISCUSSION AND CONCLUSION In conclusion, innovative scaffolds with novel modes of action, improved efficacy and acceptable physiochemical/pharmacokinetic properties were computationally identified.
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Affiliation(s)
- Abdul Wadood
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, Pakistan
- CONTACT Abdul WadoodDepartment of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan; Umer Rashid Department of Chemistry, COMSAT, Abbatabad, Pakistan
| | - Mehreen Ghufran
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | | | - Huma Khan
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Syed Sikandar Azam
- Department of Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Umer Rashid
- Department of Chemistry, COMSAT, Abbatabad, Pakistan
- CONTACT Abdul WadoodDepartment of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan; Umer Rashid Department of Chemistry, COMSAT, Abbatabad, Pakistan
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Montes GC, da Silva BNM, Rezende B, Sudo RT, Ferreira VF, de Carvalho da Silva F, da Cunha Pinto A, da Silva BV, Zapata-Sudo G. The Hypnotic, Anxiolytic, and Antinociceptive Profile of a Novel µ-Opioid Agonist. Molecules 2017; 22:molecules22050800. [PMID: 28509855 PMCID: PMC6154531 DOI: 10.3390/molecules22050800] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/17/2017] [Accepted: 04/26/2017] [Indexed: 01/09/2023] Open
Abstract
5'-4-Alkyl/aryl-1H-1,2,3-triazole derivatives PILAB 1-12 were synthesized and a pharmacological screening of these derivatives was performed to identify a possible effect on the Central Nervous System (CNS) and to explore the associated mechanisms of action. The mice received a peritoneal injection (100 µmol/kg) of each of the 12 PILAB derivatives 10 min prior to the injection of pentobarbital and the mean hypnosis times were recorded. The mean hypnosis time increased for the mice treated with PILAB 8, which was prevented when mice were administered CTOP, a µ-opioid antagonist. Locomotor and motor activities were not affected by PILAB 8. The anxiolytic effect of PILAB 8 was evaluated next in an elevated-plus maze apparatus. PILAB 8 and midazolam increased a percentage of entries and spent time in the open arms of the apparatus compared with the control group. Conversely, a decrease in the percentages of entries and time spent in the closed arms were observed. Pretreatment with naloxone, a non-specific opioid antagonist, prior to administration of PILAB 8 exhibited a reverted anxiolytic effect. PILAB 8 exhibited antinociceptive activity in the hot plate test, and reduced reactivity to formalin in the neurogenic and the inflammatory phases. These data suggest that PILAB 8 can activate µ-opioid receptors to provoke antinociceptive and anti-inflammatory effects in mice.
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Affiliation(s)
- Guilherme Carneiro Montes
- Programa de Pesquisa em Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro RJ 21941-902, Brazil.
| | | | - Bismarck Rezende
- Programa de Pesquisa em Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro RJ 21941-902, Brazil.
| | - Roberto Takashi Sudo
- Programa de Pesquisa em Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro RJ 21941-902, Brazil.
- Instituto Nacional de Ciência e Tecnologia de Fármacos e Medicamentos (INCT-INOFAR), Rio de Janeiro RJ 21941-971, Brazil.
| | | | | | - Angelo da Cunha Pinto
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro RJ 21941-909, Brazil.
- Instituto Nacional de Ciência e Tecnologia de Fármacos e Medicamentos (INCT-INOFAR), Rio de Janeiro RJ 21941-971, Brazil.
| | | | - Gisele Zapata-Sudo
- Programa de Pesquisa em Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro RJ 21941-902, Brazil.
- Instituto Nacional de Ciência e Tecnologia de Fármacos e Medicamentos (INCT-INOFAR), Rio de Janeiro RJ 21941-971, Brazil.
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Piegang BN, Tigoufack IBN, Ngnokam D, Achounna AS, Watcho P, Greffrath W, Treede RD, Nguelefack TB. Cycloartanes from Oxyanthus pallidus and derivatives with analgesic activities. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 16:97. [PMID: 26956043 PMCID: PMC4784378 DOI: 10.1186/s12906-016-1075-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 03/03/2016] [Indexed: 01/01/2023]
Abstract
Background The leaves of Oxyanthus pallidus Hiern (Rubiaceae) are extensively used in the west region of Cameroon as analgesic. These leaves are rich in cycloartanes, a subclass of triterpenes known to possess analgesic and anti-inflammatory properties. The present study aimed at evaluating the analgesic properties of three cycloartanes isolated from Oxyanthus pallidus leaves as well as their aglycones and acetylated derivatives. Methods Three cycloartanes OP3, OP5 and OP6 obtained by successive chromatography of the crude methanol extract of the leaves were hydrolysed to yield respective aglycone AOP1, AOP2, AOP3 and acetylated to HOP1, HOP2 and HOP3 respectively. Formalin-induced pain model was used to evaluate the acute anti-nociceptive properties of these cycloartanes (5 mg/kg, p.o) in mice and to determine the structure-activity relationship. Acute (24 h) and chronic (10 days) anti-hyperalgesic and anti-inflammatory activities of OP5 were evaluated at the doses of 2.5 and 5 mg/kg/day administered orally. OP6 was also evaluated in acute experiments. The antioxidant and hepato-protective activities of OP5 were evaluated at the end of the chronic treatment. Results The mixture and the individual isolated cycloartanes significantly inhibited both phases of formalin-induced pain with percentage inhibition ranging from 13 to 78 %. Acid hydrolysis did not significantly affect their antinociceptive activities while acetylation significantly reduced the effects of these compounds during the second phase of pain. OP5 and OP6 induced acute anti-hyperalgesic activity in formalin-induced mechanical hyperalgesia but not an anti-inflammatory effect. Repeated administration of OP5 for 10 days did not induce any anti-hyperalgesic effect. The evaluation of in vivo antioxidant properties showed that OP5 significantly reduced malondialdehyde and increased superoxide dismutase levels in liver without significantly affecting other oxidative stress and hepatotoxic parameters. Chronic administration of OP5 did not cause gastric ulceration. Conclusion Cycloartanes isolated from Oxyanthus pallidus possess analgesic effects but lack anti-inflammatory activities. This analgesic effect especially on inflammatory pain may be due to the presence of hydroxyl group in front of the plane. OP5 is devoid of ulcerogenic effect and possess antioxidant properties that might be of benefit to its analgesic properties.
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