Palmatine: A review of pharmacological properties and pharmacokinetics

Potential Herb-Drug Interactions in the Management of Age-Related Cognitive Dysfunction

Late-life mild cognitive impairment and dementia represent a significant burden on healthcare systems and a unique challenge to medicine due to the currently limited treatment options. Plant phytochemicals have been considered in alternative, or complementary, prevention and treatment strategies. Herbals are consumed as such, or as food supplements, whose consumption has recently increased. However, these products are not exempt from adverse effects and pharmacological interactions, presenting a special risk in aged, polymedicated individuals. Understanding pharmacokinetic and pharmacodynamic interactions is warranted to avoid undesirable adverse drug reactions, which may result in unwanted side-effects or therapeutic failure. The present study reviews the potential interactions between selected bioactive compounds (170) used by seniors for cognitive enhancement and representative drugs of 10 pharmacotherapeutic classes commonly prescribed to the middle-aged adults, often multimorbid and polymedicated, to anticipate and prevent risks arising from their co-administration. A literature review was conducted to identify mutual targets affected (inhibition/induction/substrate), the frequency of which was taken as a measure of potential interaction. Although a limited number of drugs were studied, from this work, interaction with other drugs affecting the same targets may be anticipated and prevented, constituting a valuable tool for healthcare professionals in clinical practice.

Palmatine as an Agent Against Metabolic Syndrome and Its Related Complications: A Review

Palmatine is a naturally occurring isoquinoline alkaloid with various pharmacological properties. Given its antioxidant and anti-inflammatory properties, palmatine may be able to impede the effects of metabolic syndrome (MetS) and its related diseases triggered by inflammation and oxidative stress. This review summarises the existing literature about the effects of palmatine supplementation on MetS and its complications. The evidence shows that palmatine could protect against MetS, and cardiovascular diseases, osteoporosis and osteoarthritis, which might be associated with MetS. These protective effects are mediated by the antioxidant and anti-inflammatory properties of palmatine. Although preclinical experiments have demonstrated the efficacy of palmatine against MetS and its related diseases, no human clinical trials have been performed to validate these effects. This research gap should be bridged to validate the efficacy and safety of palmatine supplementation in protecting humans against MetS and its related diseases.

Simultaneous Qualitative and Quantitative Evaluation of the Coptidis Rhizoma and Euodiae Fructus Herbal Pair by Using UHPLC-ESI-QTOF-MS and UHPLC-DAD

The herbal pair of Coptidis Rhizoma (CR) and Euodiae Fructus (EF) is a classical traditional Chinese medicine formula used for treating gastro-intestinal disorders. In this study, we established a systematic method for chemical profiling and quantification analysis of the major constituents in the CR-EF herbal pair. A method of ultra high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) for qualitative analysis was developed. Sixty-five compounds, including alkaloids, phenolics, and limonoids, were identified or tentatively assigned by comparison with reference standards or literature data. The UHPLC fingerprints of 19 batches of the CR-EF herbal pair samples were obtained and the reference fingerprint chromatograms were established. Furthermore, nine compounds among 24 common peaks of fingerprints were considered as marker components, which either had high contents or significant bioactivities, were applied to quality control of the CR-EF herbal pair by quantitative analysis. This UHPLC-DAD analysis method was validated by precision, linearity, repeatability, stability, recovery, and so on. The method was simple and sensitive, and thus reliable for quantitative and chemical fingerprint analysis for the quality evaluation and control of the CR-EF herbal pair and related traditional Chinese medicines.

UPLC-Q-TOF/MS-Based Serum and Urine Metabonomics Study on the Ameliorative Effects of Palmatine on Helicobacter pylori-Induced Chronic Atrophic Gastritis

Objective

The main objective of this study was to investigate the ameliorative effects of Palmatine (Pal) on Helicobacter pylori (H. pylori) induced chronic atrophic gastritis (CAG)

Method

Body function, serum biochemical indicators and histopathology were used to evaluate the pharmacodynamics of Pal on CAG rats. The target genes expression levels were verified and assessed by RT-PCR and immunohistochemistry (IHC). Moreover, UPLC-Q-TOF/MS analysis based on urine and serum was performed to identify the potential metabolites in the pathological process of CAG induced by H. pylori. Metabolic pathway analysis was performed to elucidate the metabolic network associated with Pal treatment of CAG.

Results

Pal (10, 20, 40 mg/kg/day) significantly restored the body function of CAG rats, reduced the serum biochemical indicators, and maintained the integrity of the gastric mucosal epithelial barrier while alleviated gastric histological damage. Metabolomics analysis shows that the therapeutic effect of Pal on CAG involves 10 metabolites and 10 metabolic pathways, of which the Taurine and hypotaurine metabolism, Glycerophospholipid metabolism and Pentose and glucuronate interconversions are closely related to the gastrointestinal protection of Pal, and these metabolic pathways crosstalk with each other due to the internet hub of citric acid cycle.

Conclusions

Metabolomics was used for the first time to identify potential biomarkers of CAG and to illuminate the therapeutic mechanism of Pal on CAG induced by H. pylori. The results provided a new insight for further research on CAG treatment.

Natural alkaloid 8-oxo-epiberberine inhibited TGF-β1-triggred epithelial-mesenchymal transition by interfering Smad3

Epithelial-mesenchymal transition (EMT), the transition of epithelial cells into mesenchymal cells, plays important roles in the metastasis of solid tumors. 8-Oxo-epiberberine (OPB) is a natural alkaloid extracted from the roots of Coptis chinensis Franch. In this study, The effect and the underlying mechanism of OPB on EMT in a TGF-β1-induced model and the inhibitory effect of OPB on lung metastasis were investigated. TGF-β1-stimulated lung cancer cells were co-treated with OPB, the morphological changes were examined. The protein expression of EMT biomarkers E-cadherin and N-cadherin was determined by Western blotting and immunofluorescence. The transcription activity of smad2/3 promoter was analyzed by a luciferase reporter assay. The effect of OPB on cell migration, invasion, and adhesion was detected by wound-healing, adhesion, and transwell assays. The in vivo anti-metastatic effect of OPB was evaluated using a 4 T1 cell xenograft mouse model. Results showed that OPB significantly reversed TGF-β1-triggered morphological changes, expression of EMT biomarkers, and migration, adhesion, and invasion. Furthermore, OPB suppressed TGF-β1-induced Smad2/3 activation, Smad3 phosphorylation and nuclear translocation, and interaction of Smad3 with Smad4. Besides, OPB dramatically decreased the metastatic nodules in the lung without affecting the growth of primary tumors. In conclusion, OPB inhibited TGF-β1-induced EMT possibly by interfering with Smad3. OPB might have therapeutic potentials for the treatment of metastatic cancers.

Highly efficient synthesis and monoamine oxidase B inhibitory profile of demethyleneberberine, columbamine and palmatine

The biosynthesis of berberine alkaloids is thought to begin with the demethylation of berberine followed by methylation reactions to generate other type berberine alkaloids. This seemingly expeditious way to access berberine alkaloids has been stagnated for over half a century due to certain vexing synthetic problems, such as low isolated yield, complex operations and toxic reagents. We further investigated this bioinspired semi-synthesis strategy and significantly improved the synthetic efficacy, by providing a practical synthetic process for demethyleneberberine (DMB), columbamine and palmatine. Furthermore, we found that DMB (IC₅₀, 9.06 μM) inhibited the activity of monoamine oxidase B (MAO-B), an enzyme that deaminates dopamine and is particularly involved in the pathology of Parkinson's disease. Besides, columbamine was able to decrease MAO-B activity by approximately 40%. These findings provide perquisites for further in vivo investigation to confirm the therapeutic potentiality of berberine alkaloids, DMB in particular.

Palmatine ameliorates Helicobacter pylori-induced chronic atrophic gastritis by inhibiting MMP-10 through ADAM17/EGFR

Palmatine (Pal), a plant-based isoquinoline alkaloid, was initially isolated from Coptidis Rhizoma (CR, Huanglian in Chinese) and considered to be a potential non-antibiotic therapeutic agent that can safely and effectively improve Helicobacter pylori (H. pylori) induced chronic atrophic gastritis (CAG). However, underlying mechanisms are unclear. In this study, we explored the protective effect of Pal on H. pylori induced CAG in vivo and in vitro. As a result, Pal alleviated the histological damage of gastric mucosa and the morphological changes of gastric epithelial cell (GES-1) caused by H. pylori. Furthermore, Pal significantly inhibited the expression of EGFR-activated ligand genes, including a disintegrin and metalloproteinase 17 (ADAM17) and heparin-binding epidermal growth factor-like growth factor (HB-EGF), and the proinflammatory factors, such as chemokine 16 (CXCL-16) and interleukin 8 (IL-8), were suppressed. In addition, Pal attenuated inflammatory infiltration of CD8⁺ T cells while promoted Reg3a expression to enhance host defense. Taken together, we concluded that Pal attenuated the MMP-10 dependent inflammatory response in the gastric mucosa by blocking ADAM17/EGFR signaling, which contributed to its gastrointestinal protective effect.

The Influence of Palmatine Isolated from Berberis sibirica Radix on Pentylenetetrazole-Induced Seizures in Zebrafish

Palmatine (PALM) and berberine (BERB) are widely identified isoquinoline alkaloids among the representatives of the Berberidaceae botanical family. The antiseizure activity of BERB was shown previously in experimental epilepsy models. We assessed the effect of PALM in a pentylenetetrazole (PTZ)-induced seizure assay in zebrafish, with BERB as an active reference compound. Both alkaloids were isolated from the methanolic root extract of Berberis sibirica by counter-current chromatography, and their ability to cross the blood–brain barrier was determined via quantitative structure–activity relationship assay. PALM exerted antiseizure activity, as confirmed by electroencephalographic analysis, and decreased c-fos and bdnf levels in PTZ-treated larvae. In a behavioral assay, PALM dose-dependently decreased PTZ-induced hyperlocomotion. The combination of PALM and BERB in ED₁₆ doses revealed hyperadditive activity towards PTZ-induced hyperlocomotion. Notably, we have indicated that both alkaloids may exert their anticonvulsant activity through different mechanisms of action. Additionally, the combination of both alkaloids in a 1:2.17 ratio (PALM: BERB) mimicked the activity of the pure extract, which indicates that these two active compounds are responsible for its anticonvulsive activity. In conclusion, our study reveals for the first time the anticonvulsant activity of PALM and suggests the combination of PALM and BERB may have higher therapeutic value than separate usage of these compounds.

Effects of palmatine on BDNF/TrkB-mediated trigeminal neuralgia

Trigeminal neuralgia (TN), a sudden, needle-like pain in the distribution area of the trigeminal nerve, can seriously affect the physical and mental health of patients. In chronic pain conditions including TN, increased levels of brain-derived neurotrophic factor (BDNF) may enhance pain transmission. This study compares the effect of palmatine administration on the expression of BDNF and its receptor TrkB (tropomyosin receptor kinase B) in trigeminal ganglion cells of Sprague-Dawley rats in a sham versus TN model group. Within 14 days of surgery, the mechanical allodynia threshold of the TN group was significantly lower than that of the sham group, while the TN + palmatine group had a higher mechanical pain sensitivity threshold than the TN group (p < 0.05). Real-time quantitative PCR, immunohistochemistry, and immunofluorescence showed that BDNF and TrkB expression in the TN group was higher than that in the sham group, while palmatine treatment could reverse these changes. Western blotting showed that palmatine treatment could reduce the elevated phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) in TN rats. Thus, the BDNF/TrkB pathway may be involved in the pain transmission process of TN, and palmatine treatment may reduce pain transmission by inhibiting the BDNF/TrkB pathway and suppressing ERK1/2 phosphorylation.

Synthesis and Structure-Activity Relationship of Palmatine Derivatives as a Novel Class of Antibacterial Agents against Helicobacter pylori

Taking palmatine (PMT) as the lead, 20 new PMT derivatives were synthesized and examined for their antibacterial activities against six tested metronidazole (MTZ)-resistant Helicobacter pylori (H. pylori) strains. The structure–activity relationship (SAR) indicated that the introduction of a suitable secondary amine substituent at the 9-position might be beneficial for potency. Among them, compound 1c exhibited the most potent activities against MTZ-resistant strains, with minimum inhibitory concentration (MIC) values of 4–16 μg/mL, better than that of the lead. It also exhibited a good safety profile with a half-lethal dose (LD₅₀) of over 1000 mg/kg. Meanwhile, 1c might exert its antimicrobial activity through targeting H. pylori urease. These results suggested that PMT derivatives might be a new family of anti-H. pylori components.