The Active Ingredient Catalpol in Rehmannia glutinosa Reduces Blood Glucose in Diabetic Rats via the AMPK Pathway.

Background: Type 2 diabetes mellitus (T2DM) poses a huge threat to population health globally, and more drugs need to be explored for treatment. In this study, we investigated the mechanism of active ingredient catalpol in Rehmannia glutinosa on reduces blood glucose in diabetic. Methods: The T2DM model was constructed by intraperitoneal injection of streptozotocin into Sprague-Dawley (SD) rats, which were randomly grouped into diabetes model group, pioglitazone group, Rehmannia glutinosa group, catalpol high-dose group, catalpol low-dose group and normal control group.The intervention was continued for 28 d, and changes in body weight, fasting blood glucose, insulin and lipid levels were observed. Results: Of all the drugs, pioglitazone had the most pronounced hypoglycemic effect, which began to decline after 2 weeks of treatment in the low-dose catalpol group and had no hypoglycemic effect in the high-dose catalpol group. Among them, Rehmannia glutinosa was able to increase serum triglyceride level, and pioglitazone effectively reduced total cholesterol level in rats. The low dose of catalpol decreased the concentration of low-density lipoprotein cholesterol (LDL), while the high dose of catalpol increased the concentration of LDL. Conclusion: As an active ingredient in Rehmannia glutinosa, catalpol has the potential to lower blood glucose and improve blood lipids in diabetes treatment, and its action may be achieved by regulating the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway, which provides a new idea for the development of new diabetes therapeutic approaches.

Catalpol attenuates ischemic stroke by promoting neurogenesis and angiogenesis via the SDF-1α/CXCR4 pathway.

BACKGROUND: Stroke is a leading cause of disability and death worldwide. Currently, there is a lack of clinically effective treatments for the brain damage following ischemic stroke. Catalpol is a bioactive compound derived from the traditional Chinese medicine Rehmannia glutinosa and shown to be protective in various neurological diseases. However, the potential roles of catalpol against ischemic stroke are still not completely clear. PURPOSE: This study aimed to further elucidate the protective effects of catalpol against ischemic stroke. METHODS: A rat permanent middle cerebral artery occlusion (pMCAO) and oxygen-glucose deprivation (OGD) model was established to assess the effect of catalpol in vivo and in vitro, respectively. Behavioral tests were used to examine the effects of catalpol on neurological function of ischemic rats. Immunostaining was performed to evaluate the proliferation, migration and differentiation of neural stem cells (NSCs) as well as the angiogenesis in each group. The protein level of related molecules was detected by western-blot. The effects of catalpol on cultured NSCs as well as brain microvascular endothelial cells (BMECs) subjected to OGD in vitro were also examined by similar methods. RESULTS: Catalpol attenuated the neurological deficits and improved neurological function of ischemic rats. It stimulated the proliferation of NSCs in the subventricular zone (SVZ), promoted their migration to the ischemic cortex and differentiation into neurons or glial cells. At the same time, catalpol increased the cerebral vessels density and the number of proliferating cerebrovascular endothelial cells in the infracted cortex of ischemic rats. The level of SDF-1α and CXCR4 in the ischemic cortex was found to be enhanced by catalpol treatment. Catalpol was also shown to promote the proliferation and migration of cultured NSCs as well as the proliferation of BMECs subjected to OGD insult in vitro. Interestingly, the impact of catalpol on cultured cells was inhibited by CXCR4 inhibitor AMD3100. Moreover, the culture medium of BMECs containing catalpol promoted the proliferation of NSCs, which was also suppressed by AMD3100. CONCLUSION: Our data demonstrate that catalpol exerts neuroprotective effects by promoting neurogenesis and angiogenesis via the SDF-1α/CXCR4 pathway, suggesting the therapeutic potential of catalpol in treating cerebral ischemia.

Transcriptome Analysis Provides Insights into Catalpol Biosynthesis in the Medicinal Plant Rehmannia glutinosa and the Functional Characterization of RgGES Genes.

Rehmannia glutinosa, a member of the Scrophulariaceae family, has been widely used in traditional Chinese medicine since ancient times. The main bioactive component of R. glutinosa is catalpol. However, the biogenesis of catalpol, especially its downstream pathway, remains unclear. To identify candidate genes involved in the biosynthesis of catalpol, transcriptomes were constructed from R. glutinosa using the young leaves of three cultivars, Beijing No. 3, Huaifeng, and Jin No. 9, as well as the tuberous roots and adventitious roots of the Jin No. 9 cultivar. As a result, 71,142 unigenes with functional annotations were generated. A comparative analysis of the R. glutinosa transcriptomes identified over 200 unigenes of 13 enzymes potentially involved in the downstream steps of catalpol formation, including 9 genes encoding UGTs, 13 for aldehyde dehydrogenases, 70 for oxidoreductases, 44 for CYP450s, 22 for dehydratases, 30 for decarboxylases, 19 for hydroxylases, and 10 for epoxidases. Moreover, two novel genes encoding geraniol synthase (RgGES), which is the first committed enzyme in catalpol production, were cloned from R. glutinosa. The purified recombinant proteins of RgGESs effectively converted GPP to geraniol. This study is the first to discover putative genes coding the tailoring enzymes mentioned above in catalpol biosynthesis, and functionally characterize the enzyme-coding gene in this pathway in R. glutinosa. The results enrich genetic resources for engineering the biosynthetic pathway of catalpol and iridoids.

Exploration of the Dynamic Variations of the Characteristic Constituents and the Degradation Products of Catalpol during the Process of Radix Rehmanniae.

Radix Rehmanniae (RR), a famous traditional Chinese medicine (TCM) widely employed in nourishing Yin and invigorating the kidney, has three common processing forms in clinical practice, including fresh Radix Rehmanniae (FRR), raw Radix Rehmanniae (RRR), and processed Radix Rehmanniae (PRR). However, until now, there has been less exploration of the dynamic variations in the characteristic constituents and degradation products of catalpol as a representative iridoid glycoside with the highest content in RR during the process from FRR to PRR. In this study, an ultra-performance liquid chromatography coupled with photodiode array detector (UPLC-PDA) method was successfully established for the simultaneous determination of ten characteristic components to explore their dynamic variations in different processed products of RR. Among them, iridoid glycosides, especially catalpol, exhibited a sharp decrease from RRR to PRR. Then, three degradation products of catalpol were detected under simulated processing conditions (100 °C, pH 4.8 acetate buffer solution), which were isolated and identified as jiofuraldehyde, cataldehyde, and norviburtinal, respectively. Cataldehyde was first reported as a new compound. Moreover, the specificity of norviburtinal in self-made PRR samples was discovered and validated, which was further confirmed by testing in commercially available PRR samples. In conclusion, our study revealed the decrease in iridoid glycosides and the production of new degradation substances during the process from FRR to PRR, which is critical for unveiling the processing mechanism of RR.

Co-catalpol alleviates fluoxetine-induced main toxicity: Involvement of ATF3/FSP1 signaling-mediated inhibition of ferroptosis.

BACKGROUND: Fluoxetine is often used as a well-known first-line antidepressant. However, it is accompanied with hepatogenic injury as its main organ toxicity, thereby limiting its application despite its superior efficacy. Fluoxetine is commonly traditionally used combined with some Chinese antidepressant prescriptions containing Rehmannia glutinosa (Dihuang) for depression therapy and hepatoprotection. Our previous experiments showed that co-Dihuang can alleviate fluoxetine-induced liver injury while efficiencies, and catalpol may be the key ingredient to characterize the toxicity-reducing and synergistic effects. However, whether co-catalpol can alleviate fluoxetine-induced liver injury and its toxicity-reducing mechanism remain unclear. PURPOSE: On the basis of the first recognition of the dose and duration at which pre-fluoxetine caused hepatic injury, co-catalpol's alleviation of fluoxetine-induced hepatic injury and its pathway was comprehensively elucidated. METHOD AND RESULTS: The hepatoprotection of co-catalpol was evaluated by serum biochemical indexes sensitive to hepatic injury and multiple staining techniques for hepatic pathologic analysis. Subsequently, the pathway by which catalpol alleviated fluoxetine-induced hepatic injury was predicted by network pharmacology to be predominantly the inhibition of ferroptosis. These were validated and confirmed in subsequent experiments with key technologies and diagnostic reagents related to ferroptosis. Further molecular docking showed that activating transcription factor 3 (ATF3) and ferroptosis suppressor protein 1 (FSP1) were the the most prospective molecules for catalpol and fluoxetine among many ferroptosis-related molecules. The critical role of ATF3/FSP1 signaling was further observed by surface plasmon resonance, diagnostic reagents, transmission electron microscopy, Western blot, real-time PCR, immunofluorescence, and immunohistochemistry. Results showed that fluoxetine directly bound to ATF3 and FSP1; agonisting ATF3 or blocking FSP1 abolished the alleviation of catalpol on fluoxetine-induced liver injury, and both exacerbated ferroptosis. Moreover, co-catalpol significantly enhanced the antidepressant efficacy of fluoxetine against depressive behaviours in mice. CONCLUSION: The hepatic impairment properties of fluoxetine were largely dependent on ATF3/FSP1 target-mediated ferroptosis. Co-catalpol alleviated fluoxetine-induced hepatic injury while enhancing its antidepressant efficacy, and that ATF3/FSP1 signaling-mediated inhibition of ferroptosis was involved in its co-administration detoxification mechanism. This study was the first to reveal the hepatotoxicity characteristics, targets, and mechanisms of fluoxetine; provide a detoxification and efficiency regimen by co-catalpol; and elucidate the detoxification mechanism.

Elucidating the therapeutic mechanism of Hengqing II decoction in Alzheimer's disease using network pharmacology and molecular docking techniques.

PURPOSE: The aim of our research was to investigate the mechanism of the Hengqing II decoction in treating Alzheimer's disease (AD) through network pharmacology and experimental validation methods. METHODS: Firstly, the major chemical compounds of Hengqing II decoction were characterized by ultra-high-performance liquid chromatography-high resolution mass spectrometry (UHPLC-Q-TOF-MS/MS), and the gene sets related to AD treatment by Hengqing II decoction were collected through the database of PubChem, Swiss TargetPrediction, and DisGeNET. Secondly, a multi-level molecular network of "Traditional Chinese medicine (TCM)-compound-target-disease" was constructed and visualized using the STRING platform and Cytoscape 3.9.1 software, and the enrichment analysis based on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway databases was performed to predict the potential active compounds and targets of Hengqing II decoction for treating AD. Finally, molecular docking simulation was applied to investigate the binding interactions between potential active compounds and key targets, and the western blotting technique was employed to examine the expression levels of AKT1, TNF-α, and NOS2 proteins affected by active compounds. RESULTS: Totally 120 compounds in Hengqing II decoction were characterized by UHPLC-Q-TOF-MS/MS. Network pharmacology results showed that potential active compounds in Hengqing II decoction in treating AD included catalpol, gastrodin, and rehmannioside D, etc., and the main target proteins were TNF-α, NOS2, and AKT1. Further functional enrichment analysis revealed that Hengqing II decoction mainly exerted its therapeutic effects on AD by regulating lipid and atherosclerosis signaling pathways, AD signaling pathways, AKT1 signaling pathways, and PTGS2 signaling pathways. CONCLUSION: Hengqing II decoction exerted therapeutic effects on AD through multi-component, multi-target, and multi-pathway regulation, and its action mechanisms were related to oxidative stress, neuroinflammation, autophagy, and other pathways. Our research laid the data foundation for further exploration of action mechanism and clarification of clinical positioning and provided new ideas and clues in TCM formula research.

Catalpolaglycone disrupts mitochondrial thermogenesis by specifically binding to a conserved lysine residue of UCP2 on the proton leak tunnel.

BACKGROUND: Catalpol (CAT), a naturally occurring iridoid glycoside sourced from the root of Rehmannia glutinosa, affects mitochondrial metabolic functions. However, the mechanism of action of CAT against pyrexia and its plausible targets remain to be fully elucidated. PURPOSE: This study aimed to identify the specific targets of CAT for blocking mitochondrial thermogenesis and to unveil the unique biological mechanism of action of the orthogonal binding mode between the hemiacetal group and lysine residue on the target protein in vivo. METHODS: Lipopolysaccharide (LPS)/ carbonyl cyanide 3-chlorophenylhydrazone (CCCP)-induced fever models were established to evaluate the potential antipyretic effects of CAT. An alkenyl-modified CAT probe was designed to identify and capture potential targets. Binding capacity was tested using in-gel imaging and a cellular thermal shift assay. The underlying antipyretic mechanisms were explored using biochemical and molecular biological methods. Catalpolaglycone (CA) was coupled with protein profile identification and molecular docking analysis to evaluate and identify its binding mode to UCP2. RESULTS: After deglycation of CAT in vivo, the hemiacetal group in CA covalently binds to Lys239 of UCP2 in the mitochondria of the liver via an ɛ-amine nucleophilic addition. This irreversible binding affects proton leakage and improves mitochondrial membrane potential and ADP/ATP transformation efficiency, leading to an antipyretic effect. CONCLUSION: Our findings highlight the potential role of CA in modulating UCP2 activity or function within the mitochondria and open new avenues for investigating the therapeutic effects of CA on mitochondrial homeostasis.

Catalpol attenuates osteoporosis in ovariectomized rats through promoting osteoclast apoptosis via the Sirt6-ERα-FasL axis.

BACKGROUND: Catalpol, a major active component of the Chinese herb Rehmannia glutinosa, possesses various pharmacological benefits, including anti-inflammatory, antidiabetic, and antitumor properties. Recent studies have reported that catalpol can attenuate bone loss and enhance bone formation. Nevertheless, the molecular mechanisms underlying its effects on osteoporosis pathogenesis remain unclear. PURPOSE: We investigated whether catalpol had a protective effect against postmenopausal osteoporosis (PMOP) and explored its exact mechanism of action. METHODS: Seventy-two rats were randomly divided into six groups: sham, model, low-dose catalpol (5 mg/kg/day), medium-dose catalpol (10 mg/kg/day), high-dose catalpol (20 mg/kg/day), and positive control (alendronate, 2.5 mg/kg). In this experiment, a ovariectomy was performed to establish a female rat model of PMOP. After 12 weeks of gavage, micro-computed tomography (micro-CT) and histochemical staining were performed to evaluate bone mass, bone microstructure and histological parameters. Furthermore, RAW 264.7 cells were induced by RANKL to form mature osteoclasts to investigate the effect of catalpol on osteoclast differentiation and apoptosis in vitro. Additionally, the osteoclast apoptosis-related proteins of Sirt6, ERα, FasL, NFATc1, cleaved-caspase 8, cleaved-caspase 3, and Bax were assessed using western blotting. The expressions of NFATc1, Ctsk, Oscar, and Trap were quantified using RT-qPCR. The apoptotic rate of the osteoclasts was determined using flow cytometry. Sirt6 knockdown was performed using siRNA gene silencing in experiments to investigate its role in catalpol-mediated osteoclast apoptosis. The deacetylation of ERα in osteoclasts was tested via co-immunoprecipitation. RESULTS: Catalpol (10 and 20 mg/kg) and alendronate (2.5 mg/kg) could significantly improve bone mineral density (BMD) and microstructure and decrease osteoclast density in ovariectomized (OVX) rats. In addition, catalpol (10 and 20 mg/kg) upregulated the expression of Sirt6, ERα, FasL, cleaved-caspase 8, cleaved-caspase 3, Bax, and downregulated the expression of NFATc1, Ctsk, Oscar, Trap both in vivo and in vitro. Catalpol also promoted ERα deacetylation and stabilized ERα protein to enhance the expression of FasL. In addition, Sirt6 knockdown by siRNA prevented ERα deacetylation and eliminated catalpol-mediated osteoclast apoptosis. CONCLUSIONS: The present study demonstrated that catalpol prevents estrogen deficiency-induced osteoporosis by promoting osteoclast apoptosis via the Sirt6-ERα-FasL axis. These findings revealed a novel molecular mechanism underpinning the impact of catalpol in the progression of osteoporosis and provided novel insights into the treatment of osteoporosis.

Catalpol rescues LPS-induced cognitive impairment via inhibition of NF-Κb-regulated neuroinflammation and up-regulation of TrkB-mediated BDNF secretion in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Septic-associated encephalopathy (SAE) is a key manifestation of sepsis. Nevertheless, specific treatment for SAE is still lacking. Catalpol is an active component derived from Rehmanniae Radix, and has been demonstrated to be a potential neuroprotective agent. However, its effect on SAE still needs to be fully explored. AIM: To address the benefits of catalpol on post-sepsis cognitive deterioration and related mechanisms. MATERIALS AND METHODS: Novel object recognition test, temporal order task, histopathology, and immunochemistry were applied to address the benefits of catalpol on LPS-triggered post-sepsis cognitive decline in mice. Xuebijing injection (10 ml/kg) has been utilized as a positive control in the above animal studies. After treatment, the catalpol content in the hippocampus was determined using LC-MS/MS. Finally, the mechanisms of catalpol were further assessed in BV2 and PC12 cells in vitro using Western blot, RT-PCR, flow cytometry, molecular docking tests, thermal shift assay, transmission electron microscopy, and immunofluorescence analysis. RESULTS: Behavior tests showed that catalpol therapy could lessen the cognitive impairment induced by LPS damage. HE, Nissl, immunofluorescence, transmission electron microscopy, and Golgi staining further reflected that catalpol treatment could restore lymphocyte infiltration, blood-brain barrier (BBB) degradation, and the decreasing complexity of dendritic trees. According to LC-MS/MS analysis, catalpol had a 136 ng/mg concentration in the hippocampus. In vitro investigation showed that catalpol could inhibit microglia M1 polarization via blocking NF-κB phosphorylation, translocation and then reducing inflammatory cytokine release in BV2 microglia cells. Brain-derived neurotrophic factor (BDNF) release up-regulation and TrkB pathway activation were observed in the catalpol treatment group in vivo and in vitro. The effect of catalpol on enhancing BDNF expression was inhibited by the specific inhibitor of TrkB (GNF-5837) in PC12 cells. Further molecular docking tests showed that catalpol formed weak hydrophobic bonds with TrkB. Besides, thermal shift assay also reflected that catalpol incubation caused a considerable change in the melting temperature of the TrkB. CONCLUSION: Catalpol alleviates LPS-triggered post-sepsis cognitive impairment by reversing neuroinflammation via blocking the NF-κB pathway, up-regulating neurotrophic factors via the activation of TrkB pathway, and preserving BBB integrity.

Catapol attenuates the aseptic inflammatory response to hepatic I/R injury in vivo and in vitro by inhibiting the HMGB1/TLR-4/NF-κB signaling pathway via the microRNA-410-3p.

BACKGROUND: Hepatic ischemia-reperfusion (I/R) injury involves inflammatory necrosis of liver cells as a significant pathological mechanism. Catapol possesses anti-inflammatory activity that is extracted from the traditional Chinese medicine, Rehmannia glutinosa. METHODS: The liver function and histopathology, Oxidative stress, and aseptic inflammatory responses were assessed in vivo, and the strongest dose group was selected. For mechanism, the expression of miR-410-3p, HMGB1, and TLR-4/NF-κB signaling pathways was detected. The dual luciferase assay can verify the targeting relationship between miR-410-3p and HMGB1. Knockdown of miR-410-3p in L02 cells is applied in interference experiments. RESULTS: CAT pre-treatment significantly decreased the liver function markers alanine and aspartate aminotransferases and reduced the areas of hemorrhage and necrosis induced by hepatic I/R injury. Additionally, it reduced the aseptic inflammatory response and oxidative stress, with the strongest protective effect observed in the high-dose CAT group. Mechanistically, CAT downregulates HMGB1, inhibits TLR-4/NF-κB signaling pathway activation, and reduces inflammatory cytokines TNF-α, and IL-1ß. In addition, the I/R-induced downregulation of microRNA-410-3p was inhibited by CAT pre-treatment in vivo and in vitro. HMGB1 was identified as a potential target of microRNA-410-3p using a dual-luciferase reporter assay. Knockdown of microRNA-410-3p abolished the inhibitory effect of CAT on HMGB1, p-NF-κB, and p-IκB-α protein expression. CONCLUSIONS: Our study showed that CAT pre-treatment has a protective effect against hepatic I/R injury in rats. Specifically, CAT attenuates the aseptic inflammatory response to hepatic I/R injury in vivo and in vitro by inhibiting the HMGB1/TLR-4/NF-κB signaling pathway via the microRNA-410-3p.

Progress of research into the pharmacological effect and clinical application of the traditional Chinese medicine Rehmanniae Radix.

The traditional Chinese medicine (TCM) Rehmanniae Radix (RR) refers to the fresh or dried root tuber of the plant Rehmannia glutinosa Libosch of the family Scrophulariaceae. As a traditional Chinese herbal medicine (CHM), it possesses multiple effects, including analgesia, sedation, anti-inflammation, antioxidation, anti-tumor, immunomodulation, cardiovascular and cerebrovascular regulation, and nerve damage repair, and it has been widely used in clinical practice. In recent years, scientists have extensively studied the active components and pharmacological effects of RR. Active ingredients mainly include iridoid glycosides (such as catalpol and aucuboside), phenylpropanoid glycosides (such as acteoside), other saccharides, and unsaturated fatty acids. In addition, the Chinese patent medicine (CPM) and Chinese decoction related to RR have also become major research subjects for TCM practitioners; one example is the Bolus of Six Drugs, which includes Rehmannia, Lily Bulb and Rehmannia Decoction, and Siwu Decoction. This article reviews recent literature on RR; summarizes the studies on its chemical constituents, pharmacological effects, and clinical applications; and analyzes the progress and limitations of current investigations to provide reference for further exploration and development of RR.

Potential benefits of Rehmanniae Radix after ancient rice-steaming process in promotion of antioxidant activity in rats' health.

Rice steam processed product of Rehmanniae Radix (RSRR), one of the processed products of Rehmanniae Radix (RR), is popular as an herbal medicine and food. However, the health-promoting effects and mechanisms of RSRR are still unclear. In this study, 10-week-old Sprague-Dawley female rats were treated with different processed products of RR. No organ coefficient differences were observed between RSRR and the control group, indicating that RSRR did not cause damage to the rats. Compared with other RR products, superoxide dismutase, glutathione, and catalase levels were significantly higher and malondialdehyde levels were significantly lower in the RSRR group, indicating that RSRR exerted a better antioxidant effect. Gene expression analysis showed that hemoglobin genes (Hba-a1, Hba-a2, Hbb-bs, Hbb, Hbq1b, Hbb-b1, and LOC103694857) may be potential biomarkers to evaluate the antioxidant effect of RSRR. Antioxidation-related signaling pathways in GO annotation, including cellular oxidant detoxification, hydrogen peroxide metabolic process, hemoglobin complex, and oxygen binding signaling pathways were significantly enriched, indicating these pathways may represent the antioxidant mechanism of RSRR. To explore the main active compounds primarily responsible for the antioxidant activity of RSRR, UPLC-Q-TOF-MS was used and six components (catalpol, rehmannioside A, rehmannioside D, melittoside, ajugol, and verbascoside) were identified in rat serum. Catalpol and rehmannioside A were predicted to be the major active components by network pharmacology. These results suggested that RSRR exhibits antioxidant activity and has health-promoting properties. This study provides a scientific basis for the antioxidant mechanism and clinical use of RSRR.

Anti-inflammatory effect and mechanism of catalpol in various inflammatory diseases.

Catalpol is a kind of iridoid glucoside, widely found in a variety of plants, mostly extracted from the rhizome of the traditional medicinal herb rehmanniae. It has various biological activities such as anti-inflammatory, antioxidant, and antitumor. The anti-inflammatory effects of catalpol have been demonstrated in a variety of diseases, such as neurological diseases, atherosclerosis, renal diseases, respiratory diseases, digestive diseases, bone and joint diseases, eye diseases, and periodontitis. The purpose of this review is to summarize the existing literature on the anti-inflammatory effects of catalpol in a variety of inflammatory diseases over the last decade and to focus on the anti-inflammatory mechanisms of catalpol.

Protective effects and possible mechanisms of catalpol against diabetic nephropathy in animal models: a systematic review and meta-analysis.

Aim of the Study: Rehmannia glutinosa is a core Chinese herbal medicine for the treatment of diabetes and diabetic nephropathy (DN). It has been used for the treatment of diabetes for over 1,000 years. Catalpol is the main active compound in Rehmannia roots. Current evidence suggests that catalpol exhibits significant anti-diabetic bioactivity, and thus it has attracted increasing research attention for its potential use in treating DN. However, no studies have systematically evaluated these effects, and its mechanism of action remains unclear. This study aimed to evaluate the effects of catalpol on DN, as well as to summarize its possible mechanisms of action, in DN animal models. Materials and Methods: We included all DN-related animal studies with catalpol intervention. These studies were retrieved by searching eight databases from their dates of inception to July 2022. In addition, we evaluated the methodological quality of the included studies using the Systematic Review Center for Laboratory animal Experimentation (SYRCLE) risk-of-bias tool. Furthermore, we calculated the weighted standard mean difference (SMD) with 95% confidence interval (CI) using the Review Manager 5.3 software and evaluated publication bias using the Stata (12.0) software. A total of 100 studies were retrieved, of which 12 that included 231 animals were finally included in this review. Results: As compared to the control treatment, treatment with catalpol significantly improved renal function in DN animal models by restoring serum creatinine (Scr) (p = 0.0009) and blood urea nitrogen (BUN) (p < 0.00001) levels, reducing proteinuria (p < 0.00001) and fasting blood glucose (FBG) (p < 0.0001), improving kidney indices (p < 0.0001), and alleviating renal pathological changes in the animal models. In addition, it may elicit its effects by reducing inflammation and oxidative stress, improving podocyte apoptosis, regulating lipid metabolism, delaying renal fibrosis, and enhancing autophagy. Conclusion: The preliminary findings of this preclinical systematic review suggest that catalpol elicits significant protective effects against hyperglycemia-induced kidney injury. However, more high-quality studies need to be carried out in the future to overcome the methodological shortcomings identified in this review.

Catalpol Alleviates Ischemic Stroke Through Promoting Angiogenesis and Facilitating Proliferation and Differentiation of Neural Stem Cells via the VEGF-A/KDR Pathway.

Stroke is one of the leading causes of disability and death globally with a lack of effective therapeutic strategies. Catalpol is a bioactive compound derived from the traditional Chinese medicine Rehmannia glutinosa and it has been shown to be protective against various neurological diseases. The potential roles of catalpol against ischemic stroke are still not completely clear. In this study, we examined the effect and mechanism of catalpol against ischemic stroke using in vivo rat distal middle cerebral artery occlusion (dMCAO) and in vitro oxygen-glucose deprivation (OGD) models. We demonstrated that catalpol indeed attenuated the neurological deficits caused by dMCAO and improved neurological function. Catalpol remarkably promoted angiogenesis, promoted proliferation and differentiation of neural stem cells (NSCs) in the subventricular zone (SVZ), and prevented neuronal loss and astrocyte activation in the ischemic cortex or hippocampal dentate gyrus (DG) in vivo. The vascular endothelial growth factor receptor 2 (KDR, VEGFR-2) inhibitor SU5416 and VEGF-A shRNA were used to investigate the underlying mechanisms. The results showed that SU5416 administration or VEGF-A-shRNA transfection both attenuated the effects of catalpol. We also found that catalpol promoted the proliferation of cultured brain microvascular endothelial cells (BMECs) and the proliferation and differentiation of NSCs subjected to OGD insult in vitro. Interestingly, the impact of catalpol on cultured cells was also inhibited by SU5416. Moreover, catalpol was shown to protect NSCs against OGD indirectly by promoting BMEC proliferation in the co-cultured system. Taken together, catalpol showed therapeutic potential in cerebral ischemia by promoting angiogenesis and NSC proliferation and differentiation. The protective effects of catalpol were mediated through VEGF-A/KDR pathway activation.

Catalpol rescues cognitive deficits by attenuating amyloid ß plaques and neuroinflammation.

This study sought to investigate the anti-amyloid ß (Aß) and anti-neuroinflammatory effects of catalpol in an Alzheimer's disease (AD) mouse model. METHODS: The effects of catalpol on Aß formation were investigated by thioflavin T assay. The effect of catalpol on generating inflammatory cytokines from microglial cells and the cytotoxicity of microglial cells on HT22 hippocampal cells were assessed by real-time quantitative PCR, ELISA, redox reactions, and cell viability. APPswe/PS1ΔE9 mice were treated with catalpol, and their cognitive ability was investigated using the water maze and novel object recognition tests. Immunohistochemistry and immunofluorescence were used to probe for protein markers of microglia and astrocyte, Aß deposits, and NF-κB pathway activity. Aß peptides, neuroinflammation, and nitric oxide production were examined using ELISA and redox reactions. RESULTS: Catalpol potently inhibited Aß fibril and oligomer formation. In microglial cells stimulated by Aß, catalpol alleviated the expression of the proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and inducible nitric oxide synthase (iNOS) but promoted the expression of the anti-inflammatory cytokine IL-10. Catalpol alleviated the cytotoxic effects of Aß-exposed microglia on HT22 cells. Treatment with catalpol in APPswe/PS1ΔE9 mice downregulated neuroinflammation production, decreased Aß deposits in the brains and alleviated cognitive impairment. Catalpol treatment decreased the number of IBA-positive microglia and GFAP-positive astrocytes and their activities of the NF-κB pathway in the hippocampus of APPswe/PS1ΔE9 mice. CONCLUSION: The administration of catalpol protected neurons by preventing neuroinflammation and Aß deposits in an AD mouse model. Therefore, catalpol may be a promising strategy for treating AD.

ESI-LC-MS/MS based comparative multivariate metabolomic and biological profiling with dynamic molecular docking of Gmelina arborea Roxb different organs.

A comprehensive study of leaves, flowers, fruits, bark, and seeds' extracts of Gmelina arborea Roxb was performed for first time to investigate their anti-inflammatory, anti-Alzheimer, and antidiabetic activities. A thorough comparative phytochemical investigation of the five organs was performed using Tandem ESI-LC-MS. The biological investigation, further aided by multivariate data analysis and molecular docking proved the highly significant potential of using G.arborea organs' extracts as medicinal agents. Chemometric analysis of the obtained data revealed 4 distinct clusters among different samples of the 5 G.arborea (GA)organs and also confirmed that each organ was chemically distinct from the others, except for fruits and seeds which were closely correlated. Compounds anticipated to be responsible for activity were identified by LC-MS/MS. To clarify the differential chemical biomarkers of G. arborea organs, an orthogonal partial least squares discriminant analysis (OPLS-DA) was constructed. Bark exhibited it's in vitro anti-inflammatory activity through down regulation of COX-1 pro-inflammatory markers while fruits and leaves affected mainly DPP4 the marker for diabetes, and flowers were the most potent against Alzheimer maker acetylcholine (ACE) esterase. The metabolomic profiling of the 5 extracts lead to the identification of 27 compounds in negative ion mode and the differences in chemical composition were correlated to difference in activity. Iridoid glycosides were the major class of identified compounds. Molecular docking proved the different affinities of our metabolite towards different targets. Gmelina arborea Roxb. is a very important plant both economically and medicinally.

Catalpol Mitigates Alzheimer's Disease Progression by Promoting the Expression of Neural Stem Cell Exosomes Released miR-138-5p.

Alzheimer's disease (Alzheimer's disease, AD) is a neurodegenerative disease characterized by senile plaque deposition and neurofibrillary tangles. The pathogenesis of AD is complicated and the drugs used to treat AD are single-targeted drugs, which can only improve or alleviate the symptoms of patients, but cannot delay or prevent the progress of the disease. Because of its ability to act on multiple targets, multiple systems, multiple links, and multiple pathways, Chinese herbal compound prescriptions have shown unique advantages in the research and treatment of AD. Our previous study has demonstrated the protect role of the Chinese medicine Rehmannia in AD. However, the underlying mechanism remains unclear. In the present study, both in vitro and vivo experiments were employed, and we found Catalpol (Ca), the main extract of Rehmannia, could mitigate AD progression both in vitro and in vivo by promoting miR-138-5p level in neural stem cell secreted exosomes.

In vitro elicitation and detection of apigenin, catalpol and gallic acid in hairy root culture of Plantago major L. and assessment of cytotoxicity and anti-bacterial activity of its methanolic extract.

The aim of this study was to establish the hairy root (HR) culture of Plantago major to evaluate the accumulation of apigenin, catalpol and gallic acid after elicitation and investigate the biological activity of its methanolic extraction. The highest transformation frequency was obtained by Agrobacterium rhizogenes strain A4, 0.5 mg/L 6-Benzylaminopurine in pre-cultivation medium, 150 µM acetosyringone in co-cultivation medium (1/2 MS), and immersion method for inoculation of leaf explants. The production of apigenin, catalpol and gallic acid compounds were significantly affected by treatment of 1.18 mM AgNO3 at 24 h which yielded 4.30, 8.24 and 2.89-fold increase, respectively. The assessment of anti-bacterial activity showed that the methanolic extracts of the HRs elicited with 1.18 mM AgNO3 were significantly active against Proteus vulgaris (PTCC 1182) (MIC = 25 mg/mL and MBC = 25 mg/mL). Furthermore, the MTT assay revealed that the methanolic extracts of the HRs were cytotoxic on the SW-480 cell (IC50=337.56 ± 1.82 µg/mL).

[Anti-oxidative and anti-apoptotic effects and molecular mechanisms of catalpol against H_2O_2-induced oxidative damage in pancreatic ß cells (INS-1 cells)].

The present study investigated the anti-oxidative and anti-apoptotic effects and molecular mechanisms of catalpol on the H_2O_2-induced pancreatic ß-cells(INS-1 cells).The oxidative damage model of INS-1 cells was induced and optimized by the stimulation of H_2O_2 of different concentrations for different time.CCK-8 assay was used to detect cell viability after catalpol intervention(1, 5, 10, 20, 40, 80, and 160 µmol·L~(-1)) for 24 h.Intracellular reactive oxygen species(ROS), superoxide dismutase(SOD), and lipid peroxide malondialdehyde(MDA) were measured by DCFH-DA fluorescent probe, WST-1, and TBA respectively.Moreover, the apo-ptotic effect was detected by AO-EB and Annexin V-FITC/PI staining.In addition, the protein expression levels were detected by Wes-tern blot, and intracellular insulin concentration was measured by ELISA.The results showed that the oxidative damage model of INS-1 cells was stably induced by 50 µmol·L~(-1) H_2O_2 treatment for 2 h, and catalpol at 1-80 µmol·L~(-1) did not affect cell viability of INS-1 cells.Compared with the conditions in the model group, 1, 5, and 10 µmol·L~(-1) catalpol intervention for 2 h could protect INS-1 cells from oxidative damage(P<0.001), reduce ROS and MDA, increase SOD, and inhibit excessive cell apoptosis.Moreover, 1, 5, and 10 µmol·L~(-1) catalpol could also up-regulate the phosphorylation of nuclear transcription factor NF-E2 related factors, negatively regulate Kelch-like ECH-associated protein 1(Keap1), phosphorylation of extracellular signal-regulated kinase(ERK), and heme oxyge-nase 1(HO-1), and promote the protein expression of pancreatic-duodenal homeobox factor-1(PDX-1) and glucose transporter 2(GLUT2).In addition, 1, 5, and 10 µmol·L~(-1) catalpol increased insulin secretion of INS-1 cells under oxidative damage in the high-glucose culture medium, indicating function recovery of pancreatic ß cells.PDX-1 is a key nuclear transcription factor of pancreatic ß cell function that directly regulates GLUT2 and insulin synthesis, and affects glucose homeostasis.In conclusion, catalpol can reduce the oxidative damage and apoptosis of INS-1 cells, activate antioxidant pathway, protect the function of pancreatic ß cells, and improve insulin synthesis and secretion.