Active components of Bupleurum chinense and Angelica biserrata showed analgesic effects in formalin induced pain by acting on Nav1.7

Effects of plant extracts and derivatives on cardiac K+, Nav, and Cav channels: a review

Natural products (NPs) are endless sources of compounds for fighting against several pathologies. Many dysfunctions, including cardiovascular disorders, such as cardiac arrhythmias have their modes of action regulation of the concentration of electrolytes inside and outside the cell targeting ion channels. Here, we highlight plant extracts and secondary metabolites' effects on the treatment of related cardiac pathologies on hERG, Nav, and Cav of cardiomyocytes. The natural product's pharmacology of expressed receptors like alpha-adrenergic receptors causes an influx of Ca2+ ions through receptor-operated Ca2+ ion channels. We also examine the NPs associated with cardiac contractions such as myocardial contractility by reducing the L-type calcium current and decreasing the intracellular calcium transient, inhibiting the K+ induced contractions, decreasing amplitude of myocyte shortening and showed negative ionotropic and chronotropic effects due to decreasing cytosolic Ca2+. We examine whether the NPs block potassium channels, particular the hERG channel and regulatory effects on Nav1.7.

Wikstroemia indica (L.) C. A. Mey. Exerts analgesic activity by inhibiting NaV1.7 channel

ETHNOPHARMACOLOGICAL RELEVANCE

Wikstroemia indica (L.) C. A. Mey. is traditionally used for the treatment of gastrointestinal disorders, respiratory illnesses, skin infections, and inflammatory conditions. Despite extensive evidence of its biological potential, including antipyretic, antimicrobial, antifungal, anti-inflammatory, and diuretic properties, there are currently no reports indicating its analgesic effects.

AIM OF THE STUDY

Crude extracts from W. indica stems were examined for anti-nociceptive activity. Additionally, an in-depth investigation was conducted to uncover the molecular basis for the possible analgesic phenomenon.

MATERIALS AND METHODS

W. indica stems were subjected to ethanol extraction. To evaluate the in vivo analgesic activity, both chemical and physical-induced pain models were employed. Additionally, single-cell electrophysiological recordings were performed on human embryonic kidney 293T (HEK293T) cells expressing NaV1.7 channel.

RESULTS

Crude extracts derived from W. indica exhibited significant efficacy in mitigating the pain sensation, as evidenced by their substantial effects in both acetic acid-induced and heat-induced pain models. Further screening unveiled osthenol as a key bioactive compound responsible for mediating the analgesic properties of W. indica. Osthenol directly interacts with the pore domain of NaV1.7 channels, leading to channel inhibition. Importantly, this interaction is independent of any changes in the channel gating modifier domain.

CONCLUSION

Both W. indica and osthenol demonstrate potential as effective anti-nociceptive agents in preclinical studies. Their analgesic effects are likely achieved by inhibiting the NaV1.7 channel, which is crucial in pain initiation, transmission, and modulation. These results elucidate the molecular basis of the W. indica as a pain-relieving medication. Additionally, osthenol holds great potential in advancing the development of anti-nociceptive drugs targeting the NaV1.7 channel.

Network Pharmacology and In vitro Experimental Verification to Explore the Mechanism of Chaiqin Qingning Capsule in the Treatment of Pain

BACKGROUND

Chaiqin Qingning capsule (CQQNC) has been used to relieve pain in practice. However, the active components, pain targets, and molecular mechanisms for pain control are unclear.

OBJECTIVE

To explore the active components and potential mechanisms of the analgesic effect of CQQNC through network pharmacology and in vitro experiments.

METHODS

The main active components and the corresponding targets of CQQNC were screened from the TCMSP and the SwissTargetPrediction databases. Pain-related targets were selected in the OMIM, Gene- Cards, and DrugBank databases. These targets were intersected to obtain potential analgesic targets. The analgesic targets were imported into the STRING and DAVID databases for protein-protein interaction (PPI), gene ontology (GO) function enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Cytoscape software (V3.7.1) was used to construct an active component-intersection network. Finally, the key components were docked with the core targets. The analgesic mechanism of CQQNC was verified by RAW264.7 cell experiment.

RESULTS

30 active CQQNC components, 617 corresponding targets, and 3,214 pain-related target genes were found. The main active components were quercetin, kaempferol, and chenodeoxycholic acid etc. The key targets were ALB, AKT1, TNF, IL6, TP53, IL1B, and SRC. CQQNC can exert an analgesic effect through PI3K-Akt, MAPK signaling pathways, etc. Molecular docking showed that these active components had good binding activities with key targets. The results of in vitro experiments showed that CQQNC could exert antiinflammatory and analgesic effects through MAPK/AKT/NF-kB signaling pathways.

CONCLUSION

CQQNC exerts pain control through inhibiting MAPK/AKT/NF-kB signaling pathways.

Voltage-gated sodium channels, potential targets of Tripterygium wilfordii Hook. f. to exert activity and produce toxicity

ETHNOPHARMACOLOGY RELEVANCE

Tripterygium wilfordii Hook. f. has been widely used in clinical practice due to its good anti-inflammatory and analgesic activities. However, its application is limited by potential toxicity and side effects.

AIM OF THE STUDY

The study aimed to identify the mechanisms responsible for the pharmacological activity and cardiotoxicity of the main monomers of Tripterygium wilfordii.

MATERIALS AND METHODS

Database analysis predicted that ion channels may be potential targets of Tripterygium wilfordii. The regulatory effects of monomers (triptolide, celastrol, demethylzeylasteral, and wilforgine) on protein Nav1.5 and Nav1.7 were predicted and detected by Autodock and patch clamping. Then, we used the formalin-induced pain model and evaluated heart rate and myocardial zymograms to investigate the analgesic activity and cardiotoxicity of each monomer in vivo.

RESULTS

All four monomers were able to bind to Nav1.7 and Nav1.5 with different binding energies and subsequently inhibited the peak currents of both Nav1.7 and Nav1.5. The monomers all exhibited analgesic effects on formalin-induced pain; therefore, we hypothesized that Nav1.7 is one of the key analgesic targets. Demethylzeylasteral reduced heart rate and increased the level of creatine kinase-MB, thus suggesting a potential cardiac risk; data suggested that the inhibitory effect on Nav1.5 might be an important factor underlying its cardiotoxicity.

CONCLUSION

Our findings provide an important theoretical basis for the further screening of active monomers with higher levels of activity and lower levels of toxicity.

NAN-190, a 5-HT1A antagonist, alleviates inflammatory pain by targeting Nav1.7 sodium channels

AIMS

In the present study, NAN-190 [1-(2-methoxyphenyl)-4-[4-(2-phthalimido) butyl] piperazine] was identified as a Nav1.7 blocker. In the meantime, the compound could alleviate the Complete Freund's Adjuvant (CFA)-induced inflammatory pain. To understand the molecular mechanisms of NAN-190 on pain, the effect of NAN-190 on Nav1.7 sodium channels was studied.

MAIN METHODS

Inflammatory pain was induced by injection of CFA solution into the plantar side of the left hindpaw. Thermal hyperalgesia and mechanical allodynia were measured. Whole-cell patch clamp methods were used to record sodium channels and other pain-related targets in the cultured recombinant cells and dorsal root ganglion neurons.

KEY FINDINGS

Nan-190 was identified as an inhibitor of Nav1.7 sodium channels and animal experiments showed that NAN-190 significantly alleviated CFA-induced inflammatory pain. Mechanism studies demonstrated that NAN-190 was a state-dependent Nav1.7 blocker with IC₅₀ value on the inactivated state ten-fold more potent than that on the rest state. NAN-190 leftward-shifted the fast and slow inactivation curves about 9.07 mV and 38.56 mV, respectively, but had no effects on channel activation. The compound also slowed the recovery from fast and slow inactivation and showed use-dependent properties. Further, the site-directed mutagenesis experiments demonstrated that NAN-190 mainly worked on the open state of Nav1.7 channels by interacting with sites similar as local anesthetics. In DRG neurons, NAN-190 mainly blocks TTX-sensitive currents but is less sensitive to TTX-R sodium currents.

SIGNIFICANCE

Taken together, our results indicated that NAN-190 alleviated pain behaviors by blocking sodium channels by interacting with the open state.

Plant-derived natural products targeting ion channels for pain

Chronic pain affects approximately one-fifth of people worldwide and reduces quality of life and in some cases, working ability. Ion channels expressed along nociceptive pathways affect neuronal excitability and as a result modulate pain experience. Several ion channels have been identified and investigated as potential targets for new medicines for the treatment of a variety of human diseases, including chronic pain. Voltage-gated channels Na⁺ and Ca²⁺ channels, K⁺ channels, transient receptor potential channels (TRP), purinergic (P2X) channels and acid-sensing ion channels (ASICs) are some examples of ion channels exhibiting altered function or expression in different chronic pain states. Pharmacological approaches are being developed to mitigate dysregulation of these channels as potential treatment options. Since natural compounds of plant origin exert promising biological and pharmacological properties and are believed to possess less adverse effects compared to synthetic drugs, they have been widely studied as treatments for chronic pain for their ability to alter the functional activity of ion channels. A literature review was conducted using Medline, Google Scholar and PubMed, resulted in listing 79 natural compounds/extracts that are reported to interact with ion channels as part of their analgesic mechanism of action. Most in vitro studies utilized electrophysiological techniques to study the effect of natural compounds on ion channels using primary cultures of dorsal root ganglia (DRG) neurons. In vivo studies concentrated on different pain models and were conducted mainly in mice and rats. Proceeding into clinical trials will require further study to develop new, potent and specific ion channel modulators of plant origin.

Plant and fungi derived analgesic natural products targeting voltage-gated sodium and calcium channels

Voltage-gated sodium and calcium channels (VGSCs and VGCCs) play an important role in the modulation of physiologically relevant processes in excitable cells that range from action potential generation to neurotransmission. Once their expression and/or function is altered in disease, specific pharmacological approaches become necessary to mitigate the negative consequences of such dysregulation. Several classes of small molecules have been developed with demonstrated effectiveness on VGSCs and VGCCs; however, off-target effects have also been described, limiting their use and spurring efforts to find more specific and safer molecules to target these channels. There are a great number of plants and herbal preparations that have been empirically used for the treatment of diseases in which VGSCs and VGCCs are involved. Some of these natural products have progressed to clinical trials, while others are under investigation for their action mechanisms on signaling pathways, including channels. In this review, we synthesize information from ~30 compounds derived from natural sources like plants and fungi and delineate their effects on VGSCs and VGCCs in human disease, particularly pain. [Figure: see text].

Analgesic effects of saikosaponin A in a rat model of chronic inflammatory pain

Saikosaponin A (SSA) is the main active ingredient of roots of the East Asian medicinal plant, Bupleurum falcatum L. The present study was aimed at delving into the analgesic properties of SSA in a model of chronic inflammatory pain. To this end, rats were initially treated intraplantarly with complete Freund's adjuvant for induction of hyperalgesia. Twenty-four hours later, rats were acutely treated with SSA (0, 1 and 2 mg/kg, i.p.) and exposed to the Von Frey monofilament test or Randall-Selitto paw pressure test for assessment of mechanical hyperalgesia. Treatment with 2 mg/kg SSA had analgesic effects: the nocifensive reaction (paw withdrawal) occurred later and required application of the nociceptive stimulus at a stronger pressure. The analgesic effects of SSA were of magnitude comparable to that of the effects exerted by the reference compound, acetyl salicylic acid (100 mg/kg, i.p.). The well-described anti-inflammatory properties of SSA likely underlie its analgesic effects.

The Role of Saponins in the Treatment of Neuropathic Pain

Neuropathic pain is a chronic pain caused by tissue injury or disease involving the somatosensory nervous system, which seriously affects the patient's body function and quality of life. At present, most clinical medications for the treatment of neuropathic pain, including antidepressants, antiepileptic drugs, or analgesics, often have limited efficacy and non-negligible side effects. As a bioactive and therapeutic component extracted from Chinese herbal medicine, the role of the effective compounds in the prevention and treatment of neuropathic pain have gradually become a research focus to explore new analgesics. Notably, saponins have shown analgesic effects in a large number of animal models. In this review, we summarized the most updated information of saponins, related to their analgesic effects in neuropathic pain, and the recent progress on the research of therapeutic targets and the potential mechanisms. Furthermore, we put up with some perspectives on future investigation to reveal the precise role of saponins in neuropathic pain.

Qianghuo Shengshi decoction exerts anti-inflammatory and analgesic via MAPKs/CREB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese Medicine Qianghuo Shengshi decoction (QSD) is widely used in the treatment of nervous headache, rheumatoid arthritis, sciatica, allergic purpura, and other clinical diseases in China. However, the underlying mechanisms of its anti-inflammatory and analgesic effects has not been elucidated.

AIM OF THE STUDY

The aim of this study was to confirm the anti-inflammatory and analgesic effects and the underlying mechanism of QSD in vivo. In addition, this study was also to isolate and analyze the main active components of QSD by high performance liquid chromatography (HPLC).

MATERIALS AND METHODS

In this study, the acetic acid writhing test, hot plate test and ear swelling test and formalin test were carried out to explore the anti-inflammatory and analgesic effects of QSD. The doses were set to 7.8 g/kg, 15.6 g/kg and 31.2 g/kg body weight. Western blot was utilized to study further possible mechanisms of QSD. Moreover, the HPLC method was used to isolate and identify the components in the extraction of QSD.

RESULTS

Twelve characteristic peaks were recognized in the HPLC spectrum, which all were the known compounds. The QSD exhibited dose-dependent effects in anti-inflammatory and analgesic aspects. Compared with model group, the writhing times of in groups of different doses of QSD (15.6 g/kg and 31.2 g/kg (oral administration = p.o.)) were reduced by 33.0% and 45.8% and indicated the QSD showed significant (p < 0.05) peripheral analgesic effect. QSD ((31.2 g/kg), p.o.) showed significant(p < 0.05) analgesic effect in the hot plate test. Inhibition rates of QSD ((15.6 g/kg and 31.2 g/kg), p.o.) in ear swelling test induced by p-xylene were 27.5% and 54.6% and demonstrated the significant (p < 0.05) anti-inflammatory activity. QSD ((31.2 g/kg), p.o.) significantly (p < 0.05) reduced times of paw licking in formalin test, and its inhibition rates were 34.3% and 28.0% in Phase I and Phase Ⅱ response, respectively. Western blot results showed that QSD inhibited the phosphorylation of mitogen-activated protein kinase (MAPK) protein and cAMP response element-binding protein (CREB).

CONCLUSIONS

These results of this study undoubtedly confirmed that QSD expressed obvious analgesic and anti-inflammatory activities. Anti-inflammatory and analgesic effects of QSD may be achieved by regulating the MAPKs protein and further regulating the expression of CREB. In all, QSD may play an anti-inflammatory and analgesic role through a variety of active ingredients.

Kampo Formulae for the Treatment of Neuropathic Pain ∼ Especially the Mechanism of Action of Yokukansan ∼

Kampo medicine has been practiced as traditional medicine (TM) in Japan. Kampo medicine uses Kampo formulae that are composed of multiple crude drugs to make Kampo formulae. In Japan, Kampo formulae are commonly used instead of or combined with Western medicines. If drug therapy that follows the guidelines for neuropathic pain does not work or cannot be taken due to side effects, various Kampo formulae are considered as the next line of treatment. Since Kampo formulae are composed of two or more kinds of natural crude drugs, and their extracts contain many ingredients with pharmacological effects, one Kampo formula usually has multiple effects. Therefore, when selecting a formula, we consider symptoms other than pain. This review outlines the Kampo formulae that are frequently used for pain treatment and their crude drugs and the basic usage of each component. In recent years, Yokukansan (YKS) has become one of the most used Kampo formulae for pain treatment with an increasing body of baseline research available. We outline the known and possible mechanisms by which YKS exerts its pharmacologic benefits as an example of Kampo formulae's potency and holistic healing properties.

Anti-microbial Effects In Vitro and In Vivo of Alstonia scholaris

Alstonia scholaris could be used as a traditional medicinal plant in China for the treatment of acute respiratory, which might be caused by respiratory tract infections. The investigation tested the anti-infective effects of total alkaloids extract (TA) from leaves of A. scholaris, and as a result, TA inhibited herpes simplex virus type 1 (HSV-1), respiratory syncytial virus (RSV) and influenza A virus (H1N1) in vitro respectively. In addition, the survival days of mice were prolonged, and the lung weights and mortality of mice were decreased significantly, after oral administrated TA in H1N1 and beta-hemolytic streptococcus infectious models in vivo respectively. The finding supported partly the traditional usage of A. scholaris in the treatment of respiratory infections.