Novel anti-nociceptive effects of cardamonin via blocking expression of cyclooxygenase-2 and transglutaminase-2

From Plant to Chemistry: Sources of Active Opioid Antinociceptive Principles for Medicinal Chemistry and Drug Design

Pain continues to be an enormous global health challenge, with millions of new untreated or inadequately treated patients reported annually. With respect to current clinical applications, opioids remain the mainstay for the treatment of pain, although they are often associated with serious side effects. To optimize their tolerability profiles, medicinal chemistry continues to study novel ligands and innovative approaches. Among them, natural products are known to be a rich source of lead compounds for drug discovery, and they hold potential for pain management. Traditional medicine has had a long history in clinical practice due to the fact that nature provides a rich source of active principles. For instance, opium had been used for pain management until the 19th century when its individual components, such as morphine, were purified and identified. In this review article, we conducted a literature survey aimed at identifying natural products interacting either directly with opioid receptors or indirectly through other mechanisms controlling opioid receptor signaling, whose structures could be interesting from a drug design perspective.

Immunomodulatory effects and mechanisms of the extracts and secondary compounds of Zingiber and Alpinia species: a review

Zingiber and Alpinia species (family: Zingiberaceae) are popularly used in food as spices and flavoring agents and in ethnomedicine to heal numerous diseases, including immune-related disorders. However, their ethnomedicinal uses have not been sufficiently supported by scientific investigations. Numerous studies on the modulating effects of plants and their bioactive compounds on the different steps of the immune system have been documented. This review aimed to highlight up-to-date research findings and critically analyze the modulatory effects and mechanisms of the extracts and secondary compounds of several Zingiber and Alpinia species, namely, Zingiber officinale Roscoe, Z. cassumunar Roxb., Z. zerumbet (L.) Roscoe ex Sm., Alpinia galanga Linn., A. conchigera Griff, A. katsumadai Hayata, A. oxyphylla Miq., A. officinarum Hance, A. zerumbet (Pers.) Burtt. et Smith, and A. purpurata (Viell.) K. Schum. on the immune system, particularly via the inflammation-related signaling pathways. The immunomodulating activities of the crude extracts of the plants have been reported, but the constituents contributing to the activities have mostly not been identified. Among the extracts, Z. officinale extracts were the most investigated for their in vitro, in vivo, and clinical effects on the immune system. Among the bioactive metabolites, 6-, 8-, and 10-gingerols, 6-shogaol, and zerumbone from Zingiber species and cardamomin, 1'-acetoxychavicol acetate, yakuchinone, rutin, 1,8-cineole, and lectin from Alpinia species have demonstrated strong immunomodulating effects. More experimental studies using cell and animal models of immune-related disorders are necessary to further understand the underlying mechanisms, together with elaborate preclinical pharmacokinetics, pharmacodynamics, bioavailability, and toxicity studies. Many of these extracts and secondary metabolites are potential candidates for clinical development in immunomodulating agents or functional foods to prevent and treat chronic inflammatory disorders.

Emerging roles of cardamonin, a multitargeted nutraceutical in the prevention and treatment of chronic diseases

Although chronic diseases are often caused by the perturbations in multiple cellular components involved in different biological processes, most of the approved therapeutics target a single gene/protein/pathway which makes them not as efficient as they are anticipated and are also known to cause severe side effects. Therefore, the pursuit of safe, efficacious, and multitargeted agents is imperative for the prevention and treatment of these diseases. Cardamonin is one such agent that has been known to modulate different signaling molecules such as transcription factors (NF-κB and STAT3), cytokines (TNF-α, IL-1β, and IL-6) enzymes (COX-2, MMP-9 and ALDH1), other proteins and genes (Bcl-2, XIAP and cyclin D1), involved in the development and progression of chronic diseases. Multiple lines of evidence emerging from pre-clinical studies advocate the promising potential of this agent against various pathological conditions like cancer, cardiovascular diseases, diabetes, neurological disorders, inflammation, rheumatoid arthritis, etc., despite its poor bioavailability. Therefore, further studies are paramount in establishing its efficacy in clinical settings. Hence, the current review focuses on highlighting the underlying molecular mechanism of action of cardamonin and delineating its potential in the prevention and treatment of different chronic diseases.

Cardamonin induces G2/M phase arrest and apoptosis through inhibition of NF-κB and mTOR pathways in ovarian cancer

Cardamonin, a natural chalcone, is reported to induce apoptosis and inhibit cancer cell growth. However, the mechanisms underlying the therapeutic effects of cardamonin remain to be established. Here, we have focused on cardamonin-induced apoptosis in ovarian cancer cells, both in vitro and in vivo. The effects of cardamonin on cell cycle patterns and apoptotic responses of cells were assessed in this study. Western blot was employed to determine the effects of cardamonin on expression of cell cycle- and apoptosis-related proteins. Our results indicate that cardamonin suppresses cancer cell growth by inducing G2/M phase arrest and apoptosis through targeted inhibition of NF-κB and mTOR pathways. The collective findings provide novel insights into the pathways responsible for the anticancer effects of cardamonin and support its potential utility as a clinical therapeutic agent for ovarian cancer.

Possible Participation of Ionotropic Glutamate Receptors and l-Arginine-Nitric Oxide-Cyclic Guanosine Monophosphate-ATP-Sensitive K+ Channel Pathway in the Antinociceptive Activity of Cardamonin in Acute Pain Animal Models

The perception of pain caused by inflammation serves as a warning sign to avoid further injury. The generation and transmission of pain impulses involves various pathways and receptors. Cardamonin isolated from Boesenbergia rotunda (L.) Mansf. has been reported to exert antinociceptive effects in thermal and mechanical pain models; however, the precise mechanism has yet to be examined. The present study investigated the possible mechanisms involved in the antinociceptive activity of cardamonin on protein kinase C, N-methyl-d-aspartate (NMDA) and non-NMDA glutamate receptors, l-arginine/cyclic guanosine monophosphate (cGMP) mechanism, as well as the ATP-sensitive potassium (K⁺) channel. Cardamonin was administered to the animals intra-peritoneally. Present findings showed that cardamonin significantly inhibited pain elicited by intraplantar injection of phorbol 12-myristate 13-acetate (PMA, a protein kinase C activator) with calculated mean ED₅₀ of 2.0 mg/kg (0.9–4.5 mg/kg). The study presented that pre-treatment with MK-801 (NMDA receptor antagonist) and NBQX (non-NMDA receptor antagonist) significantly modulates the antinociceptive activity of cardamonin at 3 mg/kg when tested with glutamate-induced paw licking test. Pre-treatment with l-arginine (a nitric oxide precursor), ODQ (selective inhibitor of soluble guanylyl cyclase) and glibenclamide (ATP-sensitive K⁺ channel inhibitor) significantly enhanced the antinociception produced by cardamonin. In conclusion, the present findings showed that the antinociceptive activity of cardamonin might involve the modulation of PKC activity, NMDA and non-NMDA glutamate receptors, l-arginine/nitric oxide/cGMP pathway and ATP-sensitive K⁺ channel.

Cardamonin: A new player to fight cancer via multiple cancer signaling pathways

Nature's pharmacy has undoubtedly served humans as an affordable and safer health-care regime for a long times. Cardamonin, a chalconoid present in several plants has been known for a longtime to have beneficial properties towards human health. In this review, we aimed to highlight the recent advances achieved in discovering the pharmacological properties of cardamonin. Cardamonin is cardamom-derived chalcone, which plays a role in cancer treatment, immune system modulation, inflammation and pathogens killing. Through the modulation of cellular signaling pathways, cardamonin activates cell death signal to induce apoptosis in malignant cells that results in the inhibition of cancer development. Moreover, cardamonin arrests cell cycle by altering the expression of regulatory proteins during malignant cells division. Due to its relatively selective cytotoxic potential against host malignant cells, cardamonin is emerging as a promising novel experimental anticancer agent. The potential of cardamonin to target various signaling molecules, transcriptional factors, cytokines and enzymes, such as mTOR, NF-κB, Akt, STAT3, Wnt/β-catenin and COX-2 enhances the opportunity to explore it as a new multi-target therapeutic agent. The pharmacokinetic and biosafety profile of cardamonin favor it as a potentially safe biomolecule for pharmaceutical drug development.

Cardamonin as a potential treatment for melanoma induces human melanoma cell apoptosis

2′,4′-dihydroxy-6′-methoxychalcone (cardamonin) is a natural compound with anti-proliferative effects on several cancer types including nasopharyngeal carcinoma. The effects of cardamonin on melanoma cells are unknown. The present study investigated the anti-proliferative effect of cardamonin on human melanoma cell lines (M14 and A375), and the underlying apoptosis inducing mechanisms. MTS assay showed that cardamonin inhibited M14 cells viability, and a reduction of the M14 cell density was also observed. Flow cytometry showed that cardamonin induced M14 cells apoptosis in a dose-dependent manner. Western blot analysis showed protein expression in M14 and A375; the pro-apoptotic protein BAX was upregulated, while the anti-apoptotic protein B-cell lymphoma-2 was downregulated. The protein expression of cleaved caspase-8, −9 and cleaved poly (ADP-ribose) polymerase was increased, whereas P65 was decreased. Furthermore, cardamonin inhibited M14 cell migration. These findings suggest that cardamonin may be a novel anticancer treatment for human melanoma.

Reversal of Epithelial-Mesenchymal Transition by Natural Anti-Inflammatory and Pro-Resolving Lipids

Epithelial mesenchymal transition (EMT) is a key process in the progression of malignant cancer. Therefore, blocking the EMT can be a critical fast track for the development of anticancer drugs. In this paper, we update recent research output of EMT and we explore suppression of EMT by natural anti-inflammatory compounds and pro-resolving lipids.

Antinociceptive Effects of Cardamonin in Mice: Possible Involvement of TRPV₁, Glutamate, and Opioid Receptors

Pain is one of the most common cause for hospital visits. It plays an important role in inflammation and serves as a warning sign to avoid further injury. Analgesics are used to manage pain and provide comfort to patients. However, prolonged usage of pain treatments like opioids and NSAIDs are accompanied with undesirable side effects. Therefore, research to identify novel compounds that produce analgesia with lesser side effects are necessary. The present study investigated the antinociceptive potentials of a natural compound, cardamonin, isolated from Boesenbergia rotunda (L) Mansf. using chemical and thermal models of nociception. Our findings showed that intraperitoneal and oral administration of cardamonin (0.3, 1, 3, and 10 mg/kg) produced significant and dose-dependent inhibition of pain in abdominal writhing responses induced by acetic acid. The present study also demonstrated that cardamonin produced significant analgesia in formalin-, capsaicin-, and glutamate-induced paw licking tests. In the thermal-induced nociception model, cardamonin exhibited significant increase in response latency time of animals subjected to hot-plate thermal stimuli. The rota-rod assessment confirmed that the antinociceptive activities elicited by cardamonin was not related to muscle relaxant or sedative effects of the compound. In conclusion, the present findings showed that cardamonin exerted significant peripheral and central antinociception through chemical- and thermal-induced nociception in mice through the involvement of TRPV₁, glutamate, and opioid receptors.

Recent development in antihyperalgesic effect of phytochemicals: anti-inflammatory and neuro-modulatory actions

INTRODUCTION

Pain is an unpleasant sensation triggered by noxious stimulation. It is one of the most prevalent conditions, limiting productivity and diminishing quality of life. Non steroidal anti inflammatory drugs (NSAIDs) are widely used as pain relievers in present day practice as pain is mostly initiated due to inflammation. However, due to potentially serious side effects, long term use of these antihyperalgesic drugs raises concern. Therefore there is a demand to search novel medicines with least side effects. Herbal products have been used for centuries to reduce pain and inflammation, and phytochemicals are known to cause fewer side effects. However, identification of active phytochemicals of herbal medicines and clear understanding of the molecular mechanism of their action is needed for clinical acceptance.

MATERIALS AND METHODS

In this review, we have briefly discussed the cellular and molecular changes during hyperalgesia via inflammatory mediators and neuro-modulatory action involved therein. The review includes 54 recently reported phytochemicals with antihyperalgesic action, as per the literature available with PubMed, Google Scholar and Scopus.

CONCLUSION

Compounds of high interest as potential antihyperalgesic agents are: curcumin, resveratrol, capsaicin, quercetin, eugenol, naringenin and epigallocatechin gallate (EGCG). Current knowledge about molecular targets of pain and their regulation by these phytochemicals is elaborated and the scope of further research is discussed.

Cardamonin attenuates hyperalgesia and allodynia in a mouse model of chronic constriction injury-induced neuropathic pain: Possible involvement of the opioid system

Neuropathic pain arises from the injury of nervous system. The condition is extremely difficult to be treated due to the ineffectiveness and presence of various adverse effects of the currently available drugs. In the present study, we investigated the antiallodynic and antihyperlagesic properties of cardamonin, a naturally occurring chalcone in chronic constriction injury (CCI)-induced neuropathic pain mice model. Our findings showed that single and repeated dose of intra-peritoneal administration of cardamonin (3, 10, 30mg/kg) significantly inhibited (P<0.001) the chronic constriction injury-induced neuropathic pain using the Hargreaves plantar test, Randall-Selitto analgesiometer test, dynamic plantar anesthesiometer test and the cold plate test in comparison with the positive control drug used (amitriptyline hydrochloride, 20mg/kg, i.p.). Pre-treatment with naloxone hydrochloride (1mg/kg, i.p.) and naloxone methiodide (1mg/kg, s.c) significantly reversed the antiallodynic and antihyperalgesic effects of cardamonin in dynamic plantar anesthesiometer test and Hargreaves plantar test, respectively. In conclusion, the current findings demonstrated novel antiallodynic and antihyperalgesic effects of cardamonin through the activation of the opioidergic system both peripherally and centrally and may prove to be a potent lead compound for the development of neuropathic pain drugs in the future.

Cardamonin (2',4'-dihydroxy-6'-methoxychalcone) isolated from Boesenbergia rotunda (L.) Mansf. inhibits CFA-induced rheumatoid arthritis in rats

Boesenbergia rotunda (L.) Mansf. had been traditionally used as herbs to treat pain and rheumatism. Cardamonin (2',4'-dihydroxy-6'-methoxychalcone) is a compound isolated from Boesenbergia rotunda (L.) Mansf.. Previous study had shown the potential of cardamonin in inhibiting the release of pro-inflammatory cytokines such as tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in vitro. Thus, the possible therapeutic effect of cardamonin in the rheumatoid arthritis (RA) joints is postulated. This study was performed to investigate the anti-arthritic properties of cardamonin in rat model of induced RA, particularly on the inflammatory and pain response of RA. Rheumatoid arthritis paw inflammation was induced by intraplantar (i.pl.) injection of complete Freund's adjuvant (CFA) in Sprague Dawley rats. Using four doses of cardamonin (0.625, 1.25, 2.5, and 5.0mg/kg), anti-arthritic activity was evaluated through the paw edema, mechanical allodynia and thermal hyperalgesia responses. Enzyme-linked immunosorbent assay (ELISA) was carried out to evaluate the plasma level of TNF-α, IL-1β, and IL-6. Histological slides were prepared from the harvested rat paws to observe the arthritic changes in the joints. Behavioral, biochemical, and histological studies showed that cardamonin demonstrated significant inhibition on RA-induced inflammatory and pain responses as well as progression of joint destruction in rats. ELISA results showed that there was significant inhibition in TNF-α, IL-1β, and IL-6 levels in plasma of the cardamonin-treated RA rats. Overall, cardamonin possesses potential anti-arthritic properties in CFA-induced RA rat model.

Cardamonin, a Novel Antagonist of hTRPA1 Cation Channel, Reveals Therapeutic Mechanism of Pathological Pain

The increasing demand for safe and effective treatments of chronic pain has promoted the investigation of novel analgesic drugs. Some herbals have been known to be able to relieve pain, while the chemical basis and target involved in this process remained to be clarified. The current study aimed to find anti-nociceptive candidates targeting transient receptor potential ankyrin 1 (TRPA1), a receptor that implicates in hyperalgesia and neurogenic inflammation. In the current study, 156 chemicals were tested for blocking HEK293/TRPA1 ion channel by calcium-influx assay. Docking study was conducted to predict the binding modes of hit compound with TRPA1 using Discovery Studio. Cytotoxicity in HEK293 was conducted by Cell Titer-Glo assay. Additionally, cardiotoxicity was assessed via xCELLigence RTCA system. We uncovered that cardamonin selectively blocked TRPA1 activation while did not interact with TRPV1 nor TRPV4 channel. A concentration-dependent inhibitory effect was observed with IC₅₀ of 454 nM. Docking analysis of cardamonin demonstrated a compatible interaction with A-967079-binding site of TRPA1. Meanwhile, cardamonin did not significantly reduce HEK293 cell viability, nor did it impair cardiomyocyte constriction. Our data suggest that cardamonin is a selective TRPA1 antagonist, providing novel insight into the target of its anti-nociceptive activity.

Cardamonin Suppresses TGF-β1-Induced Epithelial Mesenchymal Transition via Restoring Protein Phosphatase 2A Expression

Epithelial mesenchymal transition (EMT) is the first step in metastasis and implicated in the phenotype of cancer stem cells. Therefore, understanding and controlling EMT, are essential to the prevention and cure of metastasis. In the present study, we examined, by Western blot, reverse transcription polymerase chain reaction (RT-PCR), and confocal microscopy, the effects of cardamonin (CDN) on transforming growth factor-β1 (TGF-β1)-induced EMT of A549 lung adenocarcinoma cell lines. TGF-β1 induced expression of N-cadherin and decreased expression of E-cadherin. CDN suppressed N-cadherin expression and restored E-cadherin expression. Further, TGF-β1 induced migration and invasion of A549 cancer cells, which was suppressed by CDN. TGF-β1 induced c-Jun N-terminal kinase (JNK) activation during EMT, but CDN blocked it. Protein serine/threonine phosphatase 2A (PP2A) expression in A549 cancer cells was reduced by TGF-β1 but CDN restored it. The overall data suggested that CDN suppresses TGF-β1-induced EMT via PP2A restoration, making it a potential new drug candidate that controls metastasis.

Identification of natural compound carnosol as a novel TRPA1 receptor agonist

The transient receptor potential ankyrin 1 (TRPA1) cation channel is one of the well-known targets for pain therapy. Herbal medicine is a rich source for new drugs and potentially useful therapeutic agents. To discover novel natural TRPA1 agonists, compounds isolated from Chinese herbs were screened using a cell-based calcium mobilization assay. Out of the 158 natural compounds derived from traditional Chinese herbal medicines, carnosol was identified as a novel agonist of TRPA1 with an EC₅₀ value of 12.46 µM. And the agonistic effect of carnosol on TRPA1 could be blocked by A-967079, a selective TRPA1 antagonist. Furthermore, the specificity of carnosol was verified as it showed no significant effects on two other typical targets of TRP family member: TRPM8 and TRPV3. Carnosol exhibited anti-inflammatory and anti-nociceptive properties; the activation of TRPA1 might be responsible for the modulation of inflammatory nociceptive transmission. Collectively, our findings indicate that carnosol is a new anti-nociceptive agent targeting TRPA1 that can be used to explore further biological role in pain therapy.