Role of Levo-tetrahydropalmatine and its metabolites for management of chronic pain and opioid use disorders

Fu'cupping Physical Permeation-Enhancing Technique Enhances the Therapeutic Efficacy of Corydalis yanhusuo Gel Plaster

Corydalis yanhusuo, a traditional Chinese medicine, is widely used to treat various pains, and its active ingredients are alkaloids. This study aimed to develop a new type of transdermal gel plaster containing the extract of C. yanhusuo. Studies have shown that Fu'cupping physical permeation-enhancing technique can promote the penetration of alkaloids and improve the efficacy of drugs. A transdermal gel plaster containing the extract of C. yanhusuo was prepared and optimized using an orthogonal experimental design. The skin permeation ability of the gel plaster was studied in vitro, while the anti-inflammatory and analgesic effects of the prepared patch alone or with Fu'cupping physical permeation-enhancing technique were evaluated in a rat model. The formulation of a gel plaster containing C. yanhusuo extract was successfully prepared with an optimized composition consisting of glycerin (15 g), sodium polyacrylate (2 g), silicon dioxide (0.3 g), ethanol (2 g), aluminum oxide (0.1 g), citric acid (0.05 g), the C. yanhusuo extract (3 g), and water (15 g). The cumulative transdermal permeation of dehydrocorydaline, corypalmine, tetrahydropalmatine, and corydaline in 24 h was estimated to be 569.7 ± 63.2, 74.5 ± 13.7, 82.4 ± 17.2, and 38.9 ± 8.1 µg/cm2, respectively. The in vitro diffusion of dehydrocorydaline and corydaline followed the zero-order kinetics profile, while that of corypalmine and tetrahydropalmatine followed a Higuchi equation. The prepared gel plaster significantly reduced paw swelling, downregulated inflammatory cytokines, and mitigated pain induced by mechanical or chemical stimuli. The Fu'cupping physical permeation-enhancing technique further improved the anti-inflammatory and analgesic effects of the patch. The combined application of the Fu'cupping physical permeation-enhancing technique and the alkaloid gel plaster may be effective against inflammation and pain.

Natural products as the therapeutic strategies for addiction

World Drug Report 2023 concluded that 296 million people abused drugs, 39.5 million became addiction and 494,000 died as a direct or indirect result of addiction. Addiction has become a growing problem that affects individuals, their families, societies, countries and even the world. However, treatment for addiction is only limited to some developed countries because of the high cost, difficult implementation, and time consuming. Therefore, there is an urgent need to develop a low-cost, effective drug for the development of addiction treatment in more countries, which is essential for the stability and sustainable development of the world. In this review, it provided an overview of the abuse of common addictive drugs, related disorders, and current therapeutic regimen worldwide, and summarized the mechanisms of drug addiction as reward circuits, neuroadaptation and plasticity, cognitive decision-making, genetics, and environment. According to their chemical structure, 43 natural products and 5 herbal combinations with potential to treat addiction were classified, and their sources, pharmacological effects and clinical trials were introduced. It was also found that mitragine, ibogine, L-tetrahydropalmatine and crocin had greater potential for anti-addiction.

Fluoroalkoxylated C-3 and C-9 (S)-12-bromostepholidine analogues with D1R antagonist activity

To illuminate the tolerance of fluoroalkoxylated groups at the C-3 and C-9 positions of tetrahydroprotoberberines (THPBs) on D1R activity, C-3 and C-9 fluoroalkoxylated analogues of (S)-12-bromostepholidine were prepared and evaluated. All compounds examined were D1R antagonists as measured by a cAMP assay. Our structure-activity studies herein indicate that the C-3 position tolerates a 1,1-difluoroethoxy substituent for D1R antagonist activity. Compound 13a was the most potent cAMP-based D1R antagonist identified and was also found to antagonize β-arrestin translocation in a TANGO assay. Affinity assessments at other dopamine receptors revealed that 13a is selective for D1R and unlike other naturally-occurring THPBs such as (S)-stepholidine, lacks D2R affinity. In preliminary biopharmaceutical assays, excellent BBB permeation was observed for 13a. Further pharmacological studies are warranted on (S)-stepholidine congeners to harvest their potential as a source of novel, druggable D1R-targeted agents.

Neural mechanisms of priming effects of spicy food pictures induced analgesia

In this study, the effects of the priming of spicy food pictures on pain perception were evaluated in female participants using standardized methods of pain. Results from behavior tests revealed that the priming of spicy food pictures significantly reduced pain perception, particularly at high-pain intensities. Electrophysiological analysis showed that the analgesic effects of spicy food pictures were linked to decreased pain-related event-related potentials, such as N2 and P2 amplitudes, and suppressed θ-oscillations in the sensorimotor cortex. Both N2 amplitudes and θ-oscillations activities were found to be correlated with participants' pain perception. These results suggest that spicy-arousal stimuli may act as an "antagonist" to the increase in N2 amplitudes and θ-oscillations power induced by pain and influence the neuronal networks involved in integrating spontaneous nociceptive resources, which supports the dissociation theory of pain sensation and affection. These findings highlight the potential use of spicy-arousal stimuli as an analgesic and emphasize the importance of considering both the intensity of the stimuli and the individual's emotional state in the assessment and treatment of pain.

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.

Morphine Withdrawal-Induced Hyperalgesia in Models of Acute and Extended Withdrawal Is Attenuated by l-Tetrahydropalmatine

Effective pain control is an underappreciated aspect of managing opioid withdrawal, and its absence presents a significant barrier to successful opioid detoxification. Accordingly, there is an urgent need for effective non-opioid treatments to facilitate opioid detoxification. l-Tetrahydropalmatine (l-THP) possesses powerful analgesic properties and is an active ingredient in botanical formulations used in Vietnam for the treatment of opioid withdrawal syndrome. In this study, rats receiving morphine (15 mg/kg, i.p.) for 5 days per week displayed a progressive increase in pain thresholds during acute 23 h withdrawal as assessed by an automated Von Frey test. A single dose of l-THP (5 or 7.5 mg/kg, p.o.) administered during the 4th and 5th weeks of morphine treatment significantly improves pain tolerance scores. A 7-day course of l-THP treatment in animals experiencing extended withdrawal significantly attenuates hyperalgesia and reduces the number of days to recovery to baseline pain thresholds by 61% when compared to vehicle-treated controls. This indicates that the efficacy of l-THP on pain perception extends beyond its half-life. As a non-opioid treatment for reversing a significant hyperalgesic state during withdrawal, l-THP may be a valuable addition to the currently limited arsenal of opioid detoxification treatments.

High-Throughput Sequencing Reveals That Rotundine Inhibits Colorectal Cancer by Regulating Prognosis-Related Genes

Background: Rotundine is an herbal medicine with anti-cancer effects. However, little is known about the anti-cancer effect of rotundine on colorectal cancer. Therefore, our study aimed to investigate the specific molecular mechanism of rotundine inhibition of colorectal cancer. Methods: MTT and cell scratch assay were performed to investigate the effects of rotundine on the viability, migration, and invasion ability of SW480 cells. Changes in cell apoptosis were analyzed by flow cytometry. DEGs were detected by high-throughput sequencing after the action of rotundine on SW480 cells, and the DEGs were subjected to function enrichment analysis. Bioinformatics analyses were performed to screen out prognosis-related DEGs of COAD. Followed by enrichment analysis of prognosis-related DEGs. Furthermore, prognostic models were constructed, including ROC analysis, risk curve analysis, PCA and t-SNE, Nomo analysis, and Kaplan–Meier prognostic analysis. Results: In this study, we showed that rotundine concentrations of 50 μM, 100 μM, 150 μM, and 200 μM inhibited the proliferation, migration, and invasion of SW480 cells in a time- and concentration-dependent manner. Rotundine does not induce SW480 cell apoptosis. Compared to the control group, high-throughput results showed that there were 385 DEGs in the SW480 group. And DEGs were associated with the Hippo signaling pathway. In addition, 16 of the DEGs were significantly associated with poorer prognosis in COAD, with MEF2B, CCDC187, PSD2, RGS16, PLXDC1, HELB, ASIC3, PLCH2, IGF2BP3, CLHC1, DNHD1, SACS, H1-4, ANKRD36, and ZNF117 being highly expressed in COAD and ARV1 being lowly expressed. Prognosis-related DEGs were mainly enriched in cancer-related pathways and biological functions, such as inositol phosphate metabolism, enterobactin transmembrane transporter activity, and enterobactin transport. Prognostic modeling also showed that these 16 DEGs could be used as predictors of overall survival prognosis in COAD patients. Conclusions: Rotundine inhibits the development and progression of colorectal cancer by regulating the expression of these prognosis-related genes. Our findings could further provide new directions for the treatment of colorectal cancer.

Pharmacodynamics assessment of β-carboline from the roots of Psammosilene tunicoides as analgesic compound

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Psammosilene tunicoides (W. C. Wu et C. Y. Wu) is a well-known medicinal herb for the treatment of pain, hemostasia and rheumatoid arthritis among Chinese people.

AIM OF THE STUDY

The present study aimed to investigate the antinociceptive activity and mechanism of β-carboline alkaloids 1-4 which were extracted from the roots of P. tunicoides.

MATERIALS AND METHODS

The analgesic effects were evaluated using peripheral and central pain mouse models of nociception, including the formalin test and the tail flick test. The levels of glutamic acid (Glu) and nitric oxide (NO) in cerebellar cortexes and spinal cords (L4-6) were determined. The anti-inflammatory of all compounds were then assessed on RAW264.7 cells.

RESULTS

Our results showed that compounds 1-4 had significant analgesic effects on both phases of formalin test of mice. Furthermore, all compounds showed suppressive effects on Glu in the brain and NO levels in the brain cortex and the spinal cord. Except for compound 1, the others could extend the pain threshold of hot water tail-flick in mice. In addition, compounds 2 and 3 (60 μmol/kg) could decrease GABAAα1 protein levels in spinal cord. All compounds exhibited anti-inflammatory effects by inhibiting lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells with half-maximal inhibitory concentration (IC₅₀) 1.1-34.9 μM.

CONCLUSION

β-carboline alkaloids from the roots of P. tunicoides had significant analgesic activity by both central and peripheral mechanisms. Our findings suggested that regulating the release of NO or Glu or GABAα1 are some of the mechanisms of analgesic activity of β-carboline alkaloids.

The Analgesic Properties of Corydalis yanhusuo

Corydalis yanhusuo extract (YHS) has been used for centuries across Asia for pain relief. The extract is made up of more than 160 compounds and has been identified as alkaloids, organic acids, volatile oils, amino acids, alcohols, and sugars. However, the most crucial biological active constituents of YHS are alkaloids; more than 80 have been isolated and identified. This review paper aims to provide a comprehensive review of the phytochemical and pharmacological effects of these alkaloids that have significant ties to analgesia.