Loganin attenuates diabetic nephropathy in C57BL/6J mice with diabetes induced by streptozotocin and fed with diets containing high level of advanced glycation end products

Effects of undescribed iridoids in Patrinia punctiflora on insulin resistance in HepG2 cells

Patrinia punctiflora is a medical and edible Chinese herb with high nutritional and medicinal value. The continuing study of its chemical constituents led to the isolation of six iridoids, which were previously unreported compounds, patriscabioins PU (1-6). Their structures were characterized and confirmed with NMR (1D & 2D), HRMS, IR and UV. Among them, compound 5 was screened to evaluate its insulin resistance activity on an IR-HepG-2 cell model. Compound 5 had no cytotoxicity compared with the control group and could promote glucose uptake in IR-HepG-2 cells. Through further mechanism studies, the undescribed compound 5 could increase the expression levels of PI-3 K, p-AKT, GLUT4 and p-GSK3β proteins. Moreover, the expression of PEPCK and G6Pase proteins, which are key gluconeogenic enzymes, was also inhibited. Thus, compound 5 promotes the transfer of GLUT4 to the plasma membrane by activating the PI-3 K/AKT signaling pathway, at the same time, promotes glycogen synthesis and inhibits the onset of gluconeogenesis, which in turn ameliorates insulin resistance.

Silk fibroin microspheres loaded Rehmannia Liuwei extract for the protection of endothelial cells from the inhibitory effects

Liuwei Dihuang (LWDH) is a multi-component and multi-target Chinese herbal compound widely used for treating chronic conditions such as diabetes, diabetic nephropathy, hypertension, osteoporosis, and chronic kidney disease. However, traditional Chinese medicine (TCM) preparations like decoction and pill face limitations, including low active component concentration, limited bioavailability, short half-life, and the need for high dosage, which may increase the burden on liver and kidney functions and reduce clinical efficacy. In this study, LWDH was further purified using D101 macroporous adsorption resin, resulting in a soluble extract with an active component content 53.6 times higher than that of LWDH itself. The freeze-dried LWDH extract was then encapsulated within silk fibroin (SF) microspheres to significantly enhance the sustained release performance of the drug. In a human umbilical vein endothelial cell (HUVEC) model cultured under high glucose conditions, methanol vapor-treated SF/LWDH microspheres demonstrated a decrease in the 24-hour drug release rate from 61.88 % to 34.81 %, augmenting their protective effect on endothelial cells.

Decoding the role of aldosterone in glycation-induced diabetic complications

Diabetes-mediated development of micro and macro-vascular complications is a global concern. One of the factors is hyperglycemia induced the non-enzymatic formation of advanced glycation end products (AGEs). Accumulated AGEs bind with receptor of AGEs (RAGE) causing inflammation, oxidative stress and extracellular matrix proteins (ECM) modifications responsible for fibrosis, cell damage and tissue remodeling. Moreover, during hyperglycemia, aldosterone (Aldo) secretion increases, and its interaction with mineralocorticoid receptor (MR) through genomic and non-genomic pathways leads to inflammation and fibrosis. Extensive research on individual involvement of AGEs-RAGE and Aldo-MR pathways in the development of diabetic nephropathy (DN), cardiovascular diseases (CVDs), and impaired immune system has led to the discovery of therapeutic drugs. Despite mutual repercussions, the cross-talk between AGEs-RAGE and Aldo-MR pathways remains unresolved. Hence, this review focuses on the possible interaction of Aldo and glycation in DN and CVDs, considering the clinical significance of mutual molecular targets.

Iridoids modulate inflammation in diabetic kidney disease: A review

In recent years, preclinical research on diabetic kidney disease (DKD) has surged to the forefront of scientific and clinical attention. DKD has become a pervasive complication of type 2 diabetes. Given the complexity of its etiology and pathological mechanisms, current interventions, including drugs, dietary modifications, exercise, hypoglycemic treatments and lipid-lowering methods, often fall short in achieving desired therapeutic outcomes. Iridoids, primarily derived from the potent components of traditional herbs, have been the subject of long-standing research. Preclinical data suggest that iridoids possess notable renal protective properties; however, there has been no summary of the research on their efficacy in the management and treatment of DKD. This article consolidates findings from in vivo and in vitro research on iridoids in the context of DKD and highlights their shared anti-inflammatory activities in treating this condition. Additionally, it explores how certain iridoid components modify their chemical structures through the regulation of intestinal flora, potentially bolstering their therapeutic effects. This review provides a focused examination of the mechanisms through which iridoids may prevent or treat DKD, offering valuable insights for future research endeavors. Please cite this article as: Zhou TY, Tian N, Li L, Yu R. Iridoids modulate inflammation in diabetic kidney disease: A review. J Integr Med. 2024; 22(3): 210-222.

Swertiamarin mitigates nephropathy in high-fat diet/streptozotocin-induced diabetic rats by inhibiting the formation of advanced glycation end products

CONTEXT

The molecular mechanism by which Swertiamarin (SM) prevents advanced glycation end products (AGEs) induced diabetic nephropathy (DN) has never been explored.

OBJECTIVE

To evaluate the effect of SM in preventing the progression of DN in high fat diet-streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

After 1 week of acclimatisation, the rats were divided randomly into five groups as follows: (1) Control group, which received normal chow diet; (2) High-fat diet (HFD) group which was fed diet comprising of 58.7% fat, 27.5% carbohydrate and 14.4% protein); (3) Aminoguanidine (AG) group which received HFD + 100 mg/k.b.w.AG (intraperitoneal); (4) Metformin (Met) group which received HFD + 70 mg/k.b.w. the oral dose of Met and (5) SM group which was supplemented orally with 50 mg/k.b.w.SM along with HFD. After 12 weeks all HFD fed animals were given a single 35 mg/k.b.w. dose of streptozotocin with continuous HFD feeding for additional 18 weeks. Later, various biochemical assays, urine analyses, histopathological analysis of kidneys, levels of AGEs, expression of various makers, and in-silico analysis were performed.

RESULTS

The diabetic group demonstrated oxidative stress, increased levels of AGEs, decreased renal function, fibrosis in the renal tissue, higher expression of the receptor for advanced glycation end products (RAGE), which were ameliorated in the SM treated group. In-silico analysis suggests that SM can prevent the binding of AGEs with RAGE.

CONCLUSIONS

SM ameliorated DN by inhibiting the oxidative stress induced by AGEs.HighlightsSM reduces the levels of hyperglycaemia-induced advanced glycation end products in serum and renal tissue.SM prevents renal fibrosis by inhibiting the EMT in the kidney tissue.The in-silico analysis proves that SM can inhibit the binding of various AGEs with RAGE, thereby inhibiting the AGE-RAGE axis.

Use of Monoterpenes as Potential Therapeutics in Diabetes Mellitus: A Prospective Review

Monoterpenes are secondary metabolites of plants belonging to the terpenoid class of natural products. They are the most abundant components of essential oils that are generally considered to have various pharmacological properties. These compounds are reported to have antidiabetic effects in recent years. Due to nature's complex biosynthetic machinery, they also exhibit a reasonable degree of structural complexity/diversity for further analysis in structure-activity studies. Therefore, monoterpenes as antidiabetic agents have been investigated by recent in vitro and in vivo studies extensively reported in the scientific literature and claimed by patent documents. The purpose of this survey is to provide a comprehensive and prospective review concerning the potential applications of monoterpenes in the treatment of diabetes. The data for this research were collected through the specialized databases PubMed, Scopus, Web of Science, and ScienceDirect between the years 2014 and 2022, as well as the patent databases EPO, WIPO, and USPTO. The research used 76 articles published in the leading journals in the field. The main effect observed was the antidiabetic activity of monoterpenes. This review showed that monoterpenes can be considered promising agents for prevention and/or treatment of diabetes as well as have a marked pharmaceutical potential for the development of bioproducts for therapeutics applications.

Catalpol Prevents Glomerular Angiogenesis Induced by Advanced Glycation End Products via Inhibiting Galectin-3

OBJECTIVE

The main characteristics of diabetic nephropathy (DN) at the early stage are abnormal angiogenesis of glomerular endothelial cells (GECs) and macrophage infiltration. Galectin-3 plays a pivotal role in the pathogenesis of DN via binding with its ligand, advanced glycation end products (AGEs). Catalpol, an iridoid glucoside extracted from Rehmannia glutinosa, has been found to ameliorate vascular inflammation, reduce endothelial permeability, and protect against endothelial damage in diabetic milieu. However, little is known about whether catalpol could exert an anti-angiogenesis and anti-inflammation effect induced by AGEs.

METHODS

Mouse GECs (mGECs) and RAW 264.7 macrophages were treated with different concentrations of AGEs (0, 50, 100, 200 and 400 µg/mL) for different time (0, 6, 12, 24 and 48 h) to determine the optimal concentration of AGEs and treatment time. Cells were treated with catalpol (10 µmol/L), GB1107 (1 µmol/L, galectin-3 inhibitor), PX-478 (50 µmol/L, HIF-1α inhibitor), adenovirus-green fluorescent protein (Ad-GFP) [3×107 plaque-forming unit (PFU)/mL] or Ad-galectin-3-GFP (2×108 PFU/mL), which was followed by incubation with 50 µg/mL AGEs. The levels of galectin-3, vascular endothelial growth factor A (VEGFA) and pro-angiogenic factors angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), tunica interna endothelial cell kinase-2 (Tie-2) were detected by enzymelinked immunosorbent assay (ELISA). Cell counting kit-8 (CCK-8) assay was used to evaluate the proliferation of these cells. The expression levels of galectin-3, vascular endothelial growth factor receptor 1 (VEGFR1), VEGFR2, and hypoxia-inducible factor-1α (HIF-1α) in mGECs and those of galectin-3 and HIF-1α in RAW 264.7 macrophages were detected by Western blotting and immunofluorescence (IF) staining. The rat DN model was established. Catalpol (100 mg/kg) or GB1107 (10 mg/kg) was administered intragastrically once a day for 12 weeks. Ad-galectin-3-GFP (6×107 PFU/mL, 0.5 mL) or Ad-GFP (6×106 PFU/mL, 0.5 mL) was injected into the tail vein of rats 48 h before the sacrifice of the animals. The expression of galectin-3, VEGFR1, VEGFR2, and HIF-1α in renal cortices was analyzed by Western blotting. The expression of galectin-3, F4/80 (a macrophage biomarker), and CD34 (an endothelium biomarker) in renal cortices was detected by IF staining, and collagen accumulation by Masson staining.

RESULTS

The expression levels of galectin-3 and VEGFA were significantly higher in mGECs and RAW 264.7 macrophages treated with 50 µg/mL AGEs for 48 h than those in untreated cells. Catalpol and GB1107 could block the AGEs-induced proliferation of mGECs and RAW 264.7 macrophages. Over-expression of galectin-3 was found to reduce the inhibitory effect of catalpol on the proliferation of cells. Catalpol could significantly decrease the levels of Ang-1, Ang-2 and Tie-2 released by AGEs-treated mGECs, which could be reversed by over-expression of galectin-3. Catalpol could significantly inhibit AGEs-induced expression of galectin-3, HIF-1α, VEGFR1, and VEGFR2 in mGECs. The inhibitory effect of catalpol on galectin-3 in AGEs-treated mGECs was impaired by PX-478. Moreover, catalpol attenuated the AGEs-activated HIF-1α/galectin-3 pathway in RAW 264.7 macrophages, which was weakened by PX-478. Additionally, catalpol significantly inhibited the expression of galectin-3, macrophage infiltration, collagen accumulation, and angiogenesis in the kidney of diabetic rats. Over-expression of galectin-3 could antagonize these inhibitory effects of catalpol.

CONCLUSION

Catalpol prevented the angiogenesis of mGECs and macrophage proliferation via inhibiting galectin-3. It could prevent the progression of diabetes-induced renal damage.

Loganin attenuates neuroinflammation after ischemic stroke and fracture by regulating α7nAChR-mediated microglial polarization

Fracture in acute stage of ischemic stroke can increase inflammatory response and enhance stroke injury. Loganin alleviates the symptoms of many inflammatory diseases through its anti-inflammatory effect, but its role in ischemic stroke and fracture remains to be explored. Here, mice were handled with permanent middle cerebral artery occlusion (pMCAO) followed by tibial fracture 1 day later to establish a pMCAO+fracture model. Loganin or Methyllycaconitine (MLA, a specific a7nAchR inhibitor) were intragastrically administered 2 or 0.5 h before pMCAO, respectively. And mouse motor function and infarct volume were evaluated 3 days after pMCAO. We found that loganin alleviated the neurological deficit, cerebral infarction volume, and neuronal apoptosis (NeuN⁺ TUNEL⁺ ) in mice with pMCAO+fracture. And loganin suppressed pMCAO+fracture-induced neuroinflammation by promoting M2 microglia polarization (Iba1⁺ CD206⁺ ) and inhibiting M1 microglia polarization (Iba1⁺ CD11b⁺ ). While administration with MLA reversed the protective effect of loganin on pMCAO+fracture-induced neurological deficit and neuroinflammation. Next, LPS was used to stimulate BV2 microglia to simulate pMCAO+fracture-induced inflammatory microenvironment in vitro. Loganin facilitated the transformation of LPS-stimulated BV2 cells from M1 pro-inflammatory state (CD11b⁺ ) to M2 anti-inflammatory state (CD206⁺ ), which was antagonized by treatment with MLA. And loganin induced autophagy activation in LPS-stimulated BV2 cells by activating a7nAchR. Moreover, treatment with rapamycin (an autophagy activator) neutralized the inhibitory effect of MLA on loganin induced transformation of BV2 cells to M2 phenotype. Furthermore, BV2 cells were treated with LPS, LPS + loganin, LPS + loganin+MLA, or LPS + loganin+MLA+ rapamycin to obtain conditioned medium (CM) for stimulating primary neurons. Loganin reduced the damage of primary neurons caused by LPS-stimulated BV2 microglia through activating a7nAchR and inducing autophagy activation. In conclusion, loganin played anti-inflammatory and neuroprotective roles in pMCAO + fracture mice by activating a7nAchR, enhancing autophagy and promoting M2 polarization of microglia.

Divergent Total Syntheses of Hetero-Oligomeric Iridoid Glycosides

Divergent total syntheses of the hetero-oligomeric iridoid glycosides mainly found in Dipsacus asper were achieved. Thus, loganin (1), which is important as a monomer unit, was efficiently synthesized by stereoselective reductive cyclization using secologanin (2) as a substrate. Sequential condensation reactions of derivatives of 1 and 2 as monomer units led to the first enantioselective total syntheses of the heterooligomers cantleyoside, (E)-aldosecologanin, dipsaperine, (3R, 5S)-5-carboxyvincosidic acid 22-loganin ester, and dipsanoside A.

Loganin Prevents Hepatic Steatosis by Blocking NLRP3 Inflammasome Activation

Activation of the NLRP3 inflammasome is a necessary process to induce fibrosis in nonalcoholic fatty liver disease (NAFLD). Nonalcoholic steatohepatitis (NASH) is a kind of NAFLD that encompasses the spectrum of liver disease. It is characterized by inflammation and ballooning of hepatocytes during steatosis. We tested whether inhibiting the NLRP3 inflammasome could prevent the development and pathology of NASH. We identified loganin as an inhibitor of the NLRP3 inflammasome and investigated whether in vivo administration of loganin prevented NASH symptoms using a methionine-choline deficient (MCD) diet model in mice. We found that loganin inhibited the NLRP3 inflammasome activation triggered by ATP or nigericin, as shown by suppression of the production of interleukin (IL)-1β and caspase-1 (p10) in mouse primary macrophages. The speck formation of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) was blocked by loganin, showing that the assembly of the NLRP3 inflammasome complex was impaired by loganin. Administration of loganin reduced the clinical signs of NASH in mice fed the MCD diet, including hepatic inflammation, fat accumulation, and fibrosis. In addition, loganin reduced the expression of NLRP3 inflammasome components in the liver. Our findings indicate that loganin alleviates the inflammatory symptoms associated with NASH, presumably by inhibiting NLRP3 inflammasome activation. In summary, these findings imply that loganin may be a novel nutritional and therapeutic treatment for NASH-related inflammation.

The Iridoid Glycoside Loganin Modulates Autophagic Flux Following Chronic Constriction Injury-Induced Neuropathic Pain

Autophagy facilitates the degradation of organelles and cytoplasmic proteins in a lysosome-dependent manner. It also plays a crucial role in cell damage. Whether loganin affects autophagy in chronic constriction injury (CCI)-induced neuropathic pain remains unclear. We investigated the neuroprotective effect of loganin on the autophagic-lysosomal pathway in the rat CCI model. Sprague-Dawley rats were divided into sham, CCI, sham + loganin, and CCI + loganin. Loganin (5 mg/kg/day) was intraperitoneally injected once daily, and rats were sacrificed on day 7 after CCI. This study focused on the mechanism by which loganin modulates autophagic flux after CCI. CCI enhanced the autophagic marker LC3B-II in the ipsilateral spinal cord. The ubiquitin-binding protein p62 binds to LC3B-II and integrates into autophagosomes, which are degraded by autophagy. CCI caused the accumulation of p62, indicating the interruption of autophagosome turnover. Loganin significantly attenuated the expression of Beclin-1, LC3B-II, and p62. Double immunofluorescence staining was used to confirm that LC3B-II and p62 were reduced by loganin in the spinal microglia and astrocytes. Loganin also lessened the CCI-increased colocalization of both proteins. Enhanced lysosome-associated membrane protein 2 (LAMP2) and pro-cathepsin D (pro-CTSD) in CCI rats were also attenuated by loganin, suggesting that loganin improves impaired lysosomal function and autophagic flux. Loganin also attenuated the CCI-increased apoptosis protein Bax and cleaved caspase-3. Loganin prevents CCI-induced neuropathic pain, which could be attributed to the regulation of neuroinflammation, neuronal autophagy, and associated cell death. These data suggest autophagy could be a potential target for preventing neuropathic pain.

Phytochemistry, synthesis, analytical methods, pharmacological activity, and pharmacokinetics of loganin: A comprehensive review

Iridoid glycosides (IGs) are found in many medicinal and edible plants, such as Gardenia jasminoides, Cistanche tubulosa, Eucommia ulmoides, Rehmanniae Radix, Lonicera japonica, and Cornus officinalis. Loganin, an IG, is one of the main active ingredient of Cornus officinalis Sieb. et Zucc., which approved as a medicinal and edible plant in China. Loganin has been widely concerned due to its extensive pharmacological effects, including anti-diabetic, antiinflammatory, neuroprotective, and anti-tumor activities, etc. Studies have shown that these underlying mechanisms include anti-oxidation, antiinflammation and anti-apoptosis by regulating a variety of signaling pathways, such as STAT3/NF-κB, JAK/STAT3, TLR4/NF-κB, PI3K/Akt, MCP-1/CCR2, and RAGE/Nox4/p65 NF-κB signaling pathways. In order to better understand the research status of loganin and promote its application in human health, this paper systematically summarized the phytochemistry, analysis methods, synthesis, pharmacological properties and related mechanisms, and pharmacokinetics based on the research in the past decades.

Loganin ameliorates depression-like behaviors of mice via modulation of serotoninergic system

RATIONALE

Depression is a serious neuropsychiatric disorder, which is characterized by sustaining mood disorders. Loganin, a major iridoid glycoside from Corni fructus, has a variety of pharmacological activities, including neuroprotective effect and hypnotic effect. However, little is known about the effects of loganin on stress-induced depression.

OBJECTIVE

To investigate the effects of loganin on behavioral despair of mice, and whether serotonin (5-HT) and/or noradrenaline (NE) are involved in this process.

METHODS

We tested the effectiveness of loganin using tail suspension test (TST). The possible mechanism was explored using reserpine-induced ptosis and hypothermia, and 5-HTP-induced head-twitch response in mice. The changes of 5-HT and NE in the prefrontal cortex, hippocampus, and striatum were measured through high-performance liquid chromatography (HPLC) analysis. Then, we identified the effects of depleting 5-HT and NE by PCPA (p-chlorophenylalanine) and DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride) pretreatment, respectively.

RESULTS

Loganin (12.5/50 mg/kg) induced antidepressant-like effects in mice submitted to TST. Loganin (12.5/50 mg/kg) ameliorated the reserpine-induced hypothermia and ptosis, as well as increased 5-HTP-induced head-twitch responses in mice. Loganin (50 mg/kg) significantly increased the levels of 5-HT in the prefrontal cortex, hippocampus, and striatum. Furthermore, only PCPA treatment could eliminate loganin-induced antidepressant-like effects in TST.

CONCLUSION

Loganin exerts antidepressant-like effect in the TST depending on 5-HT levels in the central nervous system, which provide a potential agent for depression therapy.

Loganin exerts a protective effect on ischemia-reperfusion-induced acute kidney injury by regulating JAK2/STAT3 and Nrf2/HO-1 signaling pathways

To investigate the role of loganin in hypoxia/reperfusion (H/R)-induced renal tubular epithelial cells and ischemia/reperfusion-induced acute kidney injury (AKI). Cells were received H/R treatment and cultured with different concentrations of loganin. The cell activity and apoptosis were detected. The expressions of apoptosis-related proteins, inflammatory factors, oxidative stress related molecules, and related molecules of JAK2/STAT3 and Nrf2/HO-1 signaling pathways were measured. AKI model of mice was established by I/R procedure, and the kidney was collected for hematoxylin and eosin (HE) staining. H/R treatment inhibited cell activity and apoptosis, but loganin attenuated the effect of H/R. Moreover, loganin inhibited H/R-induced inflammatory response and oxidative stress in tubular epithelial cells. Loganin down-regulated the expression of apoptosis-related proteins, suppressed JAK2/STAT3 pathway, and activated Nrf2/HO-1 pathway. In animal experiment, loganin reduced tubular injury in AKI mice.Loganin had anti-apoptotic, anti-inflammatory, and anti-oxidative stress effects on H/R-induced tubular epithelial cells, and could improve AKI in mice induced by I/R. This effect might be achieved by inhibiting JAK2/STAT3 and activating the Nrf2/HO-1 signaling pathway.

Combination of the Herbs Radix Rehmanniae and Cornus Officinalis Mitigated Testicular Damage From Diabetes Mellitus by Enhancing Glycolysis via the AGEs/RAGE/HIF-1α Axis

Radix Rehmanniae and Cornus Officinalis (RR-CO) have been widely used as "nourishing Yin and tonifying kidney" herb pairs for the treatment of diabetes mellitus (DM) and its complications in traditional Chinese medicine (TCM). Based on the theory of "kidney governing reproduction" in TCM, the aim of this study was to investigate the therapeutic effects of RR-CO on DM-induced reproduction damage through regulating testicular glycolysis. Moreover, the regulation of AGEs/RAGE/HIF-1α axis on the testicular glycolysis process has also been studied. Spontaneous DM model KK-Ay mice were used to investigate the protective effect of RR, CO, RR-CO on DM-induced reproductive disturbances. RR, CO, RR-CO improved DM-induced renal and testicular morphology damages. Moreover, the impaired spermatogenesis, germ cell apoptosis and motility in testis induced upon DM were also attenuated by RR, CO or RR-CO, accompanied by an increased level of glycolysis metabolomics such as l-lactate, d-Fructose 1,6-bisphosphate, etc. Meanwhile, glucose membrane transporters (GLUT1, GLUT3), monocarboxylate transporter 4 (MCT4) expression, lactate dehydrogenase (LDH) activity, HIF-1α were upregulated by RR, CO and RR-CO treatment compared with the model group, whereas AGE level and RAGE expression were decreased with the drug administration. The RR-CO group was associated with superior protective effects in comparison to RR, CO use only. Aminoguanidine (Ami) and FPS-ZM1, the AGEs and RAGE inhibitors, were used as a tool drug to study the mechanism, showing different degrees of protection against DM-induced reproductive damage. This work preliminarily sheds light on the herb pair RR-CO exhibited favorable effects against DM-induced reproductive disturbances through enhancing testicular glycolysis, which might be mediated by AGEs/RAGE/HIF-1α axis.

Loganin Inhibits Lipopolysaccharide-Induced Inflammation and Oxidative Response through the Activation of the Nrf2/HO-1 Signaling Pathway in RAW264.7 Macrophages

Inflammation caused by the excessive secretion of inflammatory mediators in abnormally activated macrophages promotes many diseases along with oxidative stress. Loganin, a major iridoid glycoside isolated from Cornus officinalis, has recently been reported to exhibit anti-inflammatory and antioxidant effects, whereas the underlying mechanism has not yet been fully clarified. Therefore, the aim of the present study is to investigate the effect of loganin on inflammation and oxidative stress in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Our results indicated that loganin treatment markedly attenuated the LPS-mediated phagocytic activity and release of nitric oxide (NO) and prostaglandin E₂, which was associated with decreased the expression of inducible NO synthase and cyclooxygenase-2. In addition, loganin suppressed the expression and their extracellular secretion of LPS-induced pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-1β. Furthermore, loganin abolished reactive oxygen species (ROS) generation, and promoted the activation of nuclear factor-E2-related factor 2 (Nrf2) and the expression of heme oxygenase-1 (HO-1) in LPS-stimulated macrophages. However, zinc protoporphyrin, a selective HO-1 inhibitor, reversed the loganin-mediated suppression of pro-inflammatory cytokines in LPS-treated macrophages. In conclusion, our findings suggest that the upregulation of the Nrf2/HO-1 signaling pathway is concerned at least in the protective effect of loganin against LPS-mediated inflammatory and oxidative stress, and that loganin can be a potential functional agent to prevent inflammatory and oxidative damage.

Adverse Effects of Thermal Food Processing on the Structural, Nutritional, and Biological Properties of Proteins

Thermal processing is one of the most important processing methods in the food industry. However, many studies have revealed that thermal processing can have detrimental effects on the nutritional and functional properties of foods because of the complex interactions among food components. Proteins are essential nutrients for humans, and changes in the structure and nutritional properties of proteins can substantially impact the biological effects of foods. This review focuses on the interactions among proteins, sugars, and lipids during thermal food processing and the effects of these interactions on the structure, nutritional value, and biological effects of proteins. In particular, the negative effects of modified proteins on human health and strategies for mitigating these detrimental effects from two perspectives, namely, reducing the formation of modified proteins during thermal processing and dietary intervention in vivo, are discussed.

Design, synthesis, and biological evaluation of a novel dual peroxisome proliferator-activated receptor alpha/delta agonist for the treatment of diabetic kidney disease through anti-inflammatory mechanisms

Diabetic kidney disease (DKD) is a major feature of the final stage of nearly all cause types of diabetes mellitus (DM). To date, few safe and effective drugs are available to treat. Peroxisome proliferator-activated receptors (PPARs), comprised of three members: PPAR-α, PPAR-δ and PPAR-γ, play a protective role in the DKD through glycemic control and lipid metabolism, whereas systemic activation of PPAR-γ causes serious side-effects in clinical trials. GFT505 is a dual PPAR-α/δ agonist, and the selectivity against PPAR-γ is still to be improved. Sulfuretin has been shown to suppress the expression of PPAR-γ and improve the pathogenesis of diabetic complications. In this study, by hybridizing the carboxylic acid of GFT505 and the parent nucleus of sulfuretin, we pioneeringly designed and synthetized a series of novel dual PPAR-α/δ agonists, expecting to provide a better benefit/risk ratio for PPARs. Of all the synthesized compounds, compound 12 was identified with highly activity on PPAR-α/δ and higher selectivity against PPAR-γ than that of GFT505 (EC₅₀: hPPAR-α: 0.26 μM vs.0.76 μM; hPPAR-δ: 0.50 μM vs.0.73 μM; hPPAR-γ: 4.22 μM vs.2.79 μM). The molecular docking studies also depicted good binding affinity of compound 12 for PPAR-α and PPAR-δ compared to GFT505. Furthermore, compound 12 exhibited an evidently renoprotective effect on the DKD through inhibiting inflammatory process, which might at least partly via JNK/NF-κB pathways in vivo and in vitro. Overall, compound 12 hold therapeutic promise for DKD.

Loganin alleviates sepsis-induced acute lung injury by regulating macrophage polarization and inhibiting NLRP3 inflammasome activation

Sepsis is a systemic inflammatory response syndrome resulted from severe infection. Excessive inflammation response plays an important role in sepsis-induced acute lung injury (ALI). Loganin is an iridoid glycoside isolated from Corni fructus and exerts an anti-inflammatory effect in multiple inflammatory diseases; however, the role of loganin in sepsis-induced ALI remains unknown. In the current study, the cecal ligation and puncture (CLP)-induced murine sepsis model was constructed to investigate the anti-inflammatory property of loganin in sepsis-induced ALI. Lipopolysaccharide (LPS)-treated Raw 264.7 cells and primary murine peritoneal macrophages were established to further explore underlying mechanism of loganin. Results showed that intragastrical administration of loganin significantly increased murine survival, reduced the alveolar structure damage and inflammatory cell infiltration. Loganin suppressed the release of the M1 macrophage-associated pro-inflammatory cytokines and induced the activation of M2-type anti-inflammatory cytokines. Besides, loganin dramatically inhibited NLRP3 inflammasome-mediated caspase-1 activation and subsequent IL-1β secretion. Further in vitro studies confirmed that loganin efficiently inhibited M1 macrophage polarization and NLRP3 inflammasome activation by blocking the extra-cellular signal-regulated kinase (ERK) and nuclear factor-kappa B (NF-κB) pathways. Taken together, the anti-inflammatory effect of loganin in sepsis-induced ALI was associated with the ERK and NF-κB pathway-mediated macrophage polarization and NLRP3 inflammasome activation. Our study offers a favorable mechanistic basis to support the therapeutic potential of loganin in anti-inflammatory diseases, such as sepsis-induced ALI.

Loganin Attenuates Septic Acute Renal Injury with the Participation of AKT and Nrf2/HO-1 Signaling Pathways

Purpose

Sepsis, a destructive inflammatory response syndrome, is the principal reason to induce death in the intensive care unit. Loganin has been proved to possess the property of anti-inflammation, antioxidant, neuroprotection, and sedation. The primary aim of this study was to evaluate whether Loganin could alleviate acute kidney injury (AKI) during sepsis and investigate the latent mechanisms.

Methods

Septic AKI models were established by cecal ligation and puncture (CLP) surgery in mice and given Loganin (20, 40, 80 mg/kg) by gavage. Lipopolysaccharides (LPS)-stimulated human kidney proximal tubular (HK2) cells incubated in Loganin (5, 10, 20 μ M) were used to explore the accurate mechanisms. Survival rate, renal function (creatinine and blood urea nitrogen), and renal pathological changes were detected in septic mice. Oxidative stress markers (SOD, GSH-Px, MDA, and SOD), mitochondrial membrane potential, mitochondrial calcium overload, and nuclear factor E2-related factor 2 (Nrf2)/heme-oxygenase 1 (HO-1) pathway activation in vivo and in vitro were determined by commercial kits and Western blot. Cell apoptosis, apoptotic-related protein (cleaved caspase-3, Bcl-2, and Bax) expression and protein kinase B (AKT) phosphorylation in vivo and in vitro were measured by TUNEL staining and Western blot. Finally, AKT blockage by 10 μM LY294002 or Nrf2 inhibition by10 μ M ML385 were utilized to prove the involvement of AKT and Nrf2/HO-1 pathway in AKI during sepsis.

Results

We found Loganin treatment (20, 40, 80 mg/kg) mitigated septic AKI reflected by elevated renal function and palliative pathological changes. Oxidative stress and apoptosis in the kidney and LPS-treated HK2 cells were also inhibited by Loganin administration, which was accompanied by AKT and Nrf2/HO-1 pathway activation. Besides, the protective effects of Loganin could be diminished by AKT or Nrf2 blockage, indicating the involvement of AKT and Nrf2/HO-1 pathway.

Conclusion

The results suggested that the protective effects of Loganin on AKI during sepsis might be mediated by AKT and Nrf2/HO-1 pathway signaling activation in kidney proximal tubular cells.

Sinomenine improve diabetic nephropathy by inhibiting fibrosis and regulating the JAK2/STAT3/SOCS1 pathway in streptozotocin-induced diabetic rats

AIMS

To investigate the therapeutic effects and potent mechanism of sinomenine (SIN) nanoliposomes on nephropathy in diabetic rats.

MAIN METHODS

The protective efficacies of SIN on the oxidative injury in renal HK-2 cell induced by hydrogen peroxide (H₂O₂) were investigated via the CCK-8 assay. Forty SD rats with streptozotocin (STZ)-induced diabetic kidney disease (DKD) were assigned to the saline group and three SIN groups (10, 20 and 40 mg/kg). During 6-week treatment, body weight, fasting glucose level and other metabolic parameters were recorded. H&E staining and changes in renal functions as well as expression levels of apoptosis and fibrosis-related factors in renal tissues were assessed. The qPCR and western blotting (WB) methods were used to detect relative expression levels of JAK/STAT/SOCS pathway-related factors in the renal tissues.

KEY FINDINGS

Cell viabilities of HK-2 cells with oxidative injury were obviously improved by incubating with SIN at 320 μg/mL for 92.9%. Significantly up-regulated GPX1, SOD2 and GSH contributed to the down-regulated ROS content in SIN-treated groups. Moreover, 6-week administration of SIN improved renal functions and worsening nephropathy morphology of DKD rats. SIN also ameliorated gradually increased renal cell apoptosis, suppressed expression levels of fibrosis-related proteins as well as IL-6 and ICAM-1, and regulated JAK2/STAT3/SOCS1 pathway, thereby exhibited protective effects on renal tissues of DKD rats.

CONCLUSION

SIN protects nephrocytes and decreases renal tissue injury via inhibiting oxidative stress, reducing renal cell apoptosis and fibrosis, regulating the JAK2/STAT3/SOCS1 pathway in DKD rats.

Loganin alleviates macrophage infiltration and activation by inhibiting the MCP-1/CCR2 axis in diabetic nephropathy

BACKGROUND/AIMS

The theory of inflammation is one of the important theories in the pathogenesis of diabetic nephropathy (DN). We herein aimed to explore whether loganin affected macrophage infiltration and activation upon diabetic nephropathy (DN) by a spontaneous DN mice and a co-culture system of glomerular mesangial cells (GMCs) and macrophage cells (RAW264.7) which was induced by advanced glycation end products (AGEs).

METHODS AND KEY FINDINGS

Loganin showed remarkable capacity on protecting renal from damage by mitigating diabetic symptoms, improving the histomorphology of the kidney, decreasing the expression of extracellular matrix such as FN, COL-IV and TGF-β, reversing the production of IL-12 and IL-10 and decreasing the number of infiltrating macrophages in the kidney. Moreover, loganin showed markedly effects by suppressing iNOS and CD16/32 expressions (M1 markers), increasing Arg-1 and CD206 expressions (M2 markers), which were the phenotypic transformation of macrophage. These effects may be attributed to the inhibition of the receptor for AGEs (RAGE) /monocyte chemotactic protein-1 (MCP-1)/CC chemokine receptor 2 (CCR2) signaling pathway, with significantly down-regulated expressions of RAGE, MCP-1 and CCR2 by loganin. Loganin further decreased MCP-1 secretion when RAGE was silenced, which means other target was involved in regulating the MCP-1 expression. While loganin combinated with the inhibitor of CCR2 exerted stronger anti-inhibition effects of iNOS expression, suggesting that CCR2 was the target of loganin in regulating the activation of macrophages.

SIGNIFICANCE

Loganin could ameliorate DN kidney damage by inhibiting macrophage infiltration and activation via the MCP-1/CCR2 signaling pathway in DN.

Protective Role of Tangshen Formula on the Progression of Renal Damage in db/db Mice by TRPC6/Talin1 Pathway in Podocytes

Tangshen Formula (TSF) is a Chinese Medicine formula that has been reported to alleviate proteinuria and protect renal function in humans and animals with diabetic kidney disease (DKD). However, little is known about its mechanism in improving proteinuria. The dysregulation of podocyte cell-matrix adhesion has been demonstrated to play an important role in the pathogenesis and progression of proteinuric kidney diseases including DKD. In the present study, the underlying protective mechanism of TSF on podocytes was investigated using the murine model of type 2 DKD db/db mice in vivo and advanced glycation end products (AGEs)-stimulated primary mice podocytes in vitro. Results revealed that TSF treatment could significantly mitigate reduction of podocyte numbers and foot process effacement, reduce proteinuria, and protect renal function in db/db mice. There was a significant increase in expression of transient receptor potential canonical channel 6 (TRPC6) and a decrease in expression of talin1 in podocytes of db/db mice. The results of AGEs-stimulated primary mice podocytes showed increased cell migration and actin-cytoskeleton rearrangement. Moreover, primary mice podocytes stimulated by AGEs displayed an increase in TRPC6-dependent Ca2+ influx, a loss of talin1, and translocation of nuclear factor of activated T cell (NFATC) 2. These dysregulations in mice primary podocytes stimulated by AGEs could be significantly attenuated after TSF treatment. 1-Oleoyl-2-acetyl-sn-glycerol (OAG), a TRPC6 agonist, blocked the protective role of TSF on podocyte cell-matrix adherence. In conclusion, TSF could protect podocytes from injury and reduce proteinuria in DKD, which may be mediated by the regulation of the TRPC6/Talin1 pathway in podocytes.

Loganin Attenuates High Glucose-Induced Schwann Cells Pyroptosis by Inhibiting ROS Generation and NLRP3 Inflammasome Activation

Diabetic peripheral neuropathy (DPN) is caused by hyperglycemia, which induces oxidative stress and inflammatory responses that damage nerve tissue. Excessive generation of reactive oxygen species (ROS) and NOD-like receptor protein 3 (NLRP3) inflammasome activation trigger the inflammation and pyroptosis in diabetes. Schwann cell dysfunction further promotes DPN progression. Loganin has been shown to have antioxidant and anti-inflammatory neuroprotective activities. This study evaluated the neuroprotective effect of loganin on high-glucose (25 mM)-induced rat Schwann cell line RSC96 injury, a recognized in vitro cell model of DPN. RSC96 cells were pretreated with loganin (0.1, 1, 10, 25, 50 μM) before exposure to high glucose. Loganin’s effects were examined by CCK-8 assay, ROS assay, cell death assay, immunofluorescence staining, quantitative RT–PCR and western blot. High-glucose-treated RSC96 cells sustained cell viability loss, ROS generation, NF-κB nuclear translocation, P2 × 7 purinergic receptor and TXNIP (thioredoxin-interacting protein) expression, NLRP3 inflammasome (NLRP3, ASC, caspase-1) activation, IL-1β and IL-18 maturation and gasdermin D cleavage. Those effects were reduced by loganin pretreatment. In conclusion, we found that loganin’s antioxidant effects prevent RSC96 Schwann cell pyroptosis by inhibiting ROS generation and suppressing NLRP3 inflammasome activation.

Loganin alleviates testicular damage and germ cell apoptosis induced by AGEs upon diabetes mellitus by suppressing the RAGE/p38MAPK/NF-κB pathway

Diabetes mellitus (DM) damages male reproduction at multiple levels, such as endocrine secretion, spermatogenesis and penile erection. We herein investigated the protective effects and mechanism of loganin targeting the advanced glycation end products (AGEs)/receptor for AGEs (RAGE)/p38 mitogen-activated protein kinase (p38MAPK)/NF-κB signalling pathway. Loganin relieved the general DM symptoms and decreased the blood glucose level of KK-Ay DM mice. Haematoxylin-eosin staining demonstrated that loganin ameliorated testicular histology and function and enhanced the activities of testis-specific markers lactate dehydrogenase (LDH), acid phosphatase (ACP) and gamma-glutamyl transferase (γ-GT). Loganin also showed evident anti-oxidative stress, anti-apoptotic and anti-inflammatory effects on DM-induced reproductive damage by restoring glutathione (GSH) level and superoxide dismutase (SOD) activity, as well as reducing reactive oxygen species (ROS) level and Bax/Bcl-2 ratio in vivo and in vitro. Western blotting exhibited that loganin significantly inhibited the AGEs/RAGE/p38MAPK/NF-κB signalling pathway. Acridine orange and ethidium bromide staining (AOEB) and Western blotting showed that loganin in combination with inhibitors of RAGE, p38MAPK and NF-κB exerted stronger anti-apoptotic effects on AGE-induced GC-2 cell damage compared with loganin alone. In conclusion, loganin can protect against DM-induced reproductive damage, probably by suppressing the AGEs/RAGE/p38MAPK/NF-κB pathway.

Loganin and catalpol exert cooperative ameliorating effects on podocyte apoptosis upon diabetic nephropathy by targeting AGEs-RAGE signaling

BACKGROUND/AIMS

Rehmanniae Radix (RR) and Cornus officinalis (CO) are a typical herbal pair used to treat diabetic nephropathy (DN) in clinical practice. DN can be effectively treated by catalpol (Cat) and loganin (Log), the main active components of RR and CO respectively, through combating apoptosis, oxidative stress and inflammation. Herein, a spontaneous DN and podocyte injury model induced by advanced glycation end products (AGEs), i.e. KK-Ay mice, was used to explore the cooperative effects of Log and Cat on DN and the mechanism targeting the AGEs-RAGE (receptor for AGE) pathway.

METHODS AND KEY FINDINGS

Log and Cat alone or in combination mitigated diabetic symptoms, decreased the level of fasting blood glucose, and increased that of serum insulin. The two drugs alone or in combination protected renal function from damage, prevented extracellular matrix hyperplasia and glycogen deposition, as well as alleviated the loss of podocytes detected by histological assay and immunohistochemistry. Flow cytometry revealed that Log and Cat alone or in combination relieved the apoptosis of AGEs-induced podocytes in vitro. Silencing RAGE by RNA interference played a protective role in podocyte apoptosis, whereas overexpression of it worked oppositely. Western blot exhibited that Log and Cat alone or in combination inhibited the activation of RAGE/p38 MAPK/p65 NF-κB and RAGE/Nox4/p65 NF-κB pathways in podocytes. The inhibitory effects of drug combination were more evident than those of individual treatments.

SIGNIFICANCE

Log and Cat cooperatively resisted the apoptosis of podocytes upon DN by targeting AGEs-RAGE and its downstream pathways p38 MAPK and Nox4.

Radix Rehmanniae and Corni Fructus against Diabetic Nephropathy via AGE-RAGE Signaling Pathway

BACKGROUND AND AIMS

Radix Rehmanniae and Corni Fructus (RC) have been widely applied to treat diabetic nephropathy (DN) for centuries. But the mechanism of how RC plays the therapeutic role against DN is unclear as yet.

METHODS

The information about RC was obtained from a public database. The active compounds of RC were screened by oral bioavailability (OB) and drug-likeness (DL). Gene ontology (GO) analysis was performed to realize the key targets of RC, and an active compound-potential target network was created. The therapeutic effects of RC active compounds and their key signal pathways were preliminarily probed via network pharmacology analysis and animal experiments.

RESULTS

In this study, 29 active compounds from RC and 64 key targets related to DN were collected using the network pharmacology method. The pathway enrichment analysis showed that RC regulated advanced glycosylation end product (AGE-) RAGE and IL-17 signaling pathways to treat DN. The animal experiments revealed that RC significantly improved metabolic parameters, inflammation renal structure, and function to protect the kidney against DN.

CONCLUSIONS

The results revealed the relationship between multicomponents and multitargets of RC. The administratiom of RC might remit the DM-induced renal damage through the AGE-RAGE signaling pathway to improve metabolic parameters and protect renal structure and function.

Punica granatum improves renal function in gentamicin-induced nephropathy in rats via attenuation of oxidative stress

BACKGROUND

Gentamicin is widely used as an antibiotic for the treatment of gram negative infections. Evidences indicates that oxidative stress is involved in gentamicin-induced nephrotoxicity. In Ayurvedic medicine, Punica granatum Linn. is considered as 'a pharmacy unto itself". It has been claimed in traditional literature, to treat various kidney ailments due to its antioxidant potential.

OBJECTIVE

To explore the possible mechanism of action of methanolic extract of P.granatum leaves (MPGL) in exerting a protective effect on gentamicin-induced nephropathy.

MATERIAL AND METHODS

Animals were administered with gentamicin (80 mg/kg/day i.m.) and simultaneously with MPGL (100, 200 and 400 mg/kg p.o.) or metformin (100 mg/kg p.o.) for 8 days. A satellite group was employed in order to check for reversibility of nephrotoxic effects post discontinuation of gentamicin administration. At the end of the study, all the rats were sacrificed and serum-urine parameters were investigated. Antioxidant enzymes and tumor necrosis factor alpha (TNF-α) levels were determined in the kidney tissues along with histopathological examination of kidneys.

RESULTS

Increase in serum creatinine, urea, TNF-α, lipid peroxidation along with fall in the antioxidant enzymes activity and degeneration of tubules, arterioles as revealed by histopathological examination confirmed the manifestation of nephrotoxicity caused due to gentamicin. Simultaneous administration of MPGL and gentamicin protected kidneys against nephrotoxic effects of gentamicin as evidenced from normalization of renal function parameters and amelioration of histopathological changes.

CONCLUSION

Data suggests that MPGL attenuated oxidative stress associated renal injury by preserving antioxidant enzymes, reducing lipid peroxidation and inhibiting inflammatory mediators such as TNF-α.

Effect of a polyherbal formulation in streptozotocin-induced diabetic nephropathy in wistar rats

OBJECTIVES:

Chronic kidney failure among people with diabetes mellitus (DM) is a burgeoning health problem that affects up to 25% of patients with type 2 DM. Current pharmacological treatment for diabetic nephropathy (DN) does not stop the attainment of renal complications. The intention of the current study was to explore the role of a polyherbal formulation (PHF) in diabetic-induced nephropathy in experimental animals.

MATERIALS AND METHODS:

Diabetic rats were grouped as follows and underwent the following treatment for about 16 weeks: Group I – normal rats – no treatment, Group II – DN rats – only vehicle (p.o), and Group III and IV – DN rats – PHF orally at 250 and 500 mg/kg, respectively. After the treatment, the animals were sacrificed, and lipid, renal function, and inflammatory markers were estimated. The observed microscopic changes in kidney were analyzed.

RESULTS:

Animals administered with PHF exhibited noteworthy decrease in triglycerides, total cholesterol, very low-density lipoprotein (LDL), LDL, serum creatinine, urinary protein, urinary albumin excretion rate, advanced glycation end products, type IV collagen excretion, interleukin-6, transforming growth factor-ß, and tumor necrosis factor-alpha and showed significant increase in high-density lipoprotein, urine volume, urinary urea, and urine creatinine. Histopathological examination established that administration of PHF prohibited kidney damage.

CONCLUSION:

Treatment with PHF showed beneficial effect on DN which may be due to the improvement of renal function parameters and hyperlipidemic and inflammatory mediators.

Antioxidant and cytoprotective properties of loganic acid isolated from seeds of Strychnos potatorum L. against heavy metal induced toxicity in PBMC model

Present work carried out with the objectives to isolate active component of S. potatorum and also to evaluate its free radical scavenging activity and preventing capacity against heavy metal toxicity. Solvents of different polarity were used to prepare crude extracts of S. potatorum seeds and screened for antioxidant activity. Among the crude extracts, methanolic extract was found to exhibit higher antioxidant activity (81.22%) which was fractionated by liquid-liquid partitioning method. Among the different fractions (LF1-LF4), LF-2 showed higher antioxidant activity (98.24%) as compared to other three liquid fractions and hence LF-2 was further purified by column chromatography. Among nine column fractions (CF1-CF9), fraction CF-7 was found to have higher antioxidant activity (92.14%), which was further analyzed using LC-MS and NMR and identified as loganic acid. In vitro radical scavenging assays showed remarkable antioxidant activity of loganic acid in terms of DPPH scavenging (IC₅₀ 149 µg/ml), superoxide radical scavenging (IC₅₀ 632.43 µg/ml) and hydroxyl radical scavenging (IC₅₀ 29.78 µg/ml). Loganic acid exhibited 81% prevention of heavy metal toxicity through the mechanism of inhibiting ROS generation (2046 AU vs. 5264 AU in control) and lipid peroxidation (95.01%). Thus, the active compound (loganic acid) isolated from S. potatorum has strong free radical scavenging activity and remarkable cyto-protective effect against heavy metal mediated toxicity.

Efficacy and safety of an herbal formula (KBMSI-2) in the treatment of erectile dysfunction: A preliminary clinical study

Purpose

To investigate the efficacy and safety of KBMSI-2, an herbal formula consisting of Ginseng Radix Rubra, Dioscorea tenuipes, Cornus officinalis Sieb. et Zucc., Lycium chinense Mill, and Curcuma longa Linn, for the treatment of erectile dysfunction (ED).

Materials and Methods

Patients were instructed to take placebo or 6 g of KBMSI-2 twice per day for 8 weeks, at least 1 hour after food intake. The primary outcome was a change from baseline in erectile function (EF) domain scores of the International Index of Erectile Function (IIEF) questionnaire. Secondary outcome included changes from baseline in all domain scores of the IIEF, scores on the Aging Males' Symptoms scale, and serum total testosterone levels, as well as changes in questions 2 and 3 of the Sexual Encounter Profile, responses to the Global Assessment Question, and changes in the number of ‘yes’ responses on the Androgen Deficiency in Aging Males questionnaire.

Results

Patients receiving KBMSI-2 had a statistically significant improvement in baseline IIEF-EF domain scores at 8 weeks compared to the placebo group. Intercourse satisfaction domain and the total IIEF scores also increased in the KBMSI-2 group. However, we could not find any significant differences in other efficacy variables between the groups. Only one patient had an adverse event, which was mild in severity.

Conclusions

This preliminary clinical study of KBMSI-2 shows significant improvements in EF and intercourse satisfaction, as measured by the IIEF in patients with ED. Further studies using a larger number of patients in the long term should follow.

Loganetin protects against rhabdomyolysis-induced acute kidney injury by modulating the toll-like receptor 4 signalling pathway

BACKGROUND AND PURPOSE

Acute kidney injury (AKI) is a rapid renal dysfunctional disease, for which no effective drugs or therapies are available to improve prognosis. Loganetin is a natural product with unknown bioactivities. Here, we identified a new protective effect and mechanism of Loganetin in a mouse model of AKI induced by rhabdomyolysis.

EXPERIMENTAL APPROACH

AKI was induced using glycerol by i.m. injection in mice models. Thirty minutes and 24 and 48 hr after injection of glycerol, the mice received 2 and 18 mg·kg^-1 of Loganetin i.p. respectively. Then mice blood and kidney were collected for various biochemical and histopathological studies. Mechanistic studies on modulation of AKI by Loganetin were performed using HK-2 cells and Toll-like receptor 4 (TLR4) knockout mice.

KEY RESULTS

In the Loganetin treated group, kidney damage and mortality rate were declined, and blood urea nitrogen and serum creatinine were much lower. Loganetin prevented damage to the tubular structures induced by glycerol and decreased apoptotic cells at the corticomedullary junction. In HK-2 cells, Loganetin could inhibit NF-κB pathway and pro-apoptotic genes expression. However, TLR4 was silenced by a specific shRNA, and the inhibitory effect of Loganetin in HK-2 cells vanished. Loganetin also down-regulated the expression of inflammation factors by suppressing TLR4 activity.

CONCLUSION AND IMPLICATIONS

All the results suggested that TLR4 plays a critical role in AKI development, and Loganetin ameliorates AKI by inhibiting TLR4 activity and blocking the JNK/p38 pathway, which provides a new strategy for AKI treatment.

Elucidation of the Intestinal Absorption Mechanism of Loganin in the Human Intestinal Caco-2 Cell Model

Loganin, iridoid glycosides, is the main bioactive ingredients in the plant Strychnos nux-vomica L. and demonstrates various pharmacological effects, though poor oral bioavailability in rats. In this study, the intestinal absorption mechanism of loganin was investigated using the human intestinal Caco-2 cell monolayer model in both the apical-to-basolateral (A-B) and the basolateral-to-apical (B-A) direction; additionally, transport characteristics were systematically investigated at different concentrations, pHs, temperatures, and potential transporters. The absorption permeability (PappAB) of loganin, which ranged from 12.17 to 14.78 × 10-6cm/s, was high at four tested concentrations (5, 20, 40, and 80μM), while the major permeation mechanism of loganin was found to be passive diffusion with active efflux mediated by multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP). In addition, it was found that loganin was not the substrate of efflux transporter P-glycoprotein (P-gp) since the selective inhibitor (verapamil) of the efflux transporter exhibited little effects on the transport of loganin in the human intestinal Caco-2 cells. Meanwhile, transport from the apical to the basolateral side increased 2.09-fold after addition of a MRP inhibitor and 2.32-fold after addition of a BCRP inhibitor. In summary, our results clearly demonstrate, for the first time, a good permeability of loganin in the human intestinal Caco-2 cell model and elucidate, in detail, the intestinal absorption mechanism and the effects of transporters on iridoid glycosides compounds.

Scabiosa Genus: A Rich Source of Bioactive Metabolites

The genus Scabiosa (family Caprifoliaceae) is considered large (618 scientific plant names of species) although only 62 have accepted Latin binominal names. The majority of the Scabiosa species are widely distributed in the Mediterranean region and some Scabiosa species are used in traditional medicine systems. For instance, Scabiosa columbaria L. is used traditionally against diphtheria while S. comosa Fisch. Ex Roem. and Schult. is used in Mongolian and Tibetan traditional medical settings to treat liver diseases. The richness of Scabiosa species in secondary metabolites such as iridoids, flavonoids and pentacyclic triterpenoids may contribute to its use in folk medicine. Details on the most recent and relevant pharmacological in vivo studies on the bioactive secondary metabolites isolated from Scabiosa species will be summarized and thoroughly discussed.

Impact of loganin on pro-inflammatory cytokines and depression- and anxiety-like behaviors in male diabetic rats

Behavioral disturbances are observed in most patients suffering from diabetes. According to some evidence, pro-inflammatory cytokines have a key role both in diabetes and behavioral disorders, such as anxiety and depression. In this study, the effect of chronic administration of loganin, as a bioflavonoid, was investigated on pro-inflammatory cytokines and depression- and anxiety-like behaviors in streptozotocin-induced diabetes in male Wistar rats. Blood levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were assessed by enzyme-linked immunosorbent assay method. Depression- and anxiety-like behaviors were evaluated by forced swimming test (FST), elevated plus maze (EPM), and open field test (OFT), respectively. Body weight was also measured before the interventions and after the experiments in all groups. Our findings show that loganin-treated animals had significantly lower serum concentrations of IL-6 and TNF-α compared with the diabetic group. In the EPM test, loganin treatment significantly increased the percentage of the open arm time and open arm entries. Moreover, loganin treatment significantly decreased the grooming time and restored distance traveled and center crossing in the OFT. However, it decreased immobility time in the FST. Loganin treatment also significantly restored body weight gain and attenuated blood glucose changes in the diabetic rats. These results indicate that loganin possibly alleviates depression- and anxiety-like behaviors associated with diabetes through lowering the blood glucose and pro-inflammatory cytokine levels. More research is required to show the exact mechanism of antidepressant and anxiolytic effects of loganin in diabetes.

Impact of loganin on pro-inflammatory cytokines and depression- and anxiety-like behaviors in male diabetic rats

Behavioral disturbances are observed in most patients suffering from diabetes. According to some evidence, pro-inflammatory cytokines have a key role both in diabetes and behavioral disorders, such as anxiety and depression. In this study, the effect of chronic administration of loganin, as a bioflavonoid, was investigated on pro-inflammatory cytokines and depression- and anxiety-like behaviors in streptozotocin-induced diabetes in male Wistar rats. Blood levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were assessed by enzyme-linked immunosorbent assay method. Depression- and anxiety-like behaviors were evaluated by forced swimming test (FST), elevated plus maze (EPM), and open field test (OFT), respectively. Body weight was also measured before the interventions and after the experiments in all groups. Our findings show that loganin-treated animals had significantly lower serum concentrations of IL-6 and TNF-α compared with the diabetic group. In the EPM test, loganin treatment significantly increased the percentage of the open arm time and open arm entries. Moreover, loganin treatment significantly decreased the grooming time and restored distance traveled and center crossing in the OFT. However, it decreased immobility time in the FST. Loganin treatment also significantly restored body weight gain and attenuated blood glucose changes in the diabetic rats. These results indicate that loganin possibly alleviates depression- and anxiety-like behaviors associated with diabetes through lowering the blood glucose and pro-inflammatory cytokine levels. More research is required to show the exact mechanism of antidepressant and anxiolytic effects of loganin in diabetes.

Spinal muscular atrophy: antisense oligonucleotide therapy opens the door to an integrated therapeutic landscape

Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder characterized by loss of spinal cord motor neurons, muscle atrophy and infantile death or severe disability. It is caused by severe reduction of the ubiquitously expressed survival motor neuron (SMN) protein, owing to loss of the SMN1 gene. This would be completely incompatible with survival without the presence of a quasi-identical duplicated gene, SMN2, specific to humans. SMN2 harbours a silent point mutation that favours the production of transcripts lacking exon 7 and a rapidly degraded non-functional SMNΔ7 protein, but from which functional full length SMN protein is produced at very low levels (∼10%). Since the seminal discovery of the SMA-causing gene in 1995, research has focused on the development of various SMN replacement strategies culminating, in December 2016, in the approval of the first precise molecularly targeted therapy for SMA (nusinersen), and a pivotal proof of principle that therapeutic antisense oligonucleotide (ASO) treatment can effectively target the central nervous system (CNS) to treat neurological and neuromuscular disease. Nusinersen is a steric block ASO that binds the SMN2 messenger RNA and promotes exon 7 inclusion and thus increases full length SMN expression. Here, we consider the implications of this therapeutic landmark for SMA therapeutics and discuss how future developments will need to address the challenges of delivering ASO therapies to the CNS, with appropriate efficiency and activity, and how SMN-based therapy should be used in combination with complementary strategies to provide an integrated approach to treat CNS and peripheral pathologies in SMA.

Bioactive phytochemicals that regulate the cellular processes involved in diabetic nephropathy

BACKGROUND

Owing to the multiple causative factors, the current advances in medication for diabetic nephropathy (DN) do not appear to have improved therapies for patients. Furthermore, use of multiple synthetic medications has shown various adverse effects and ultimately leads to deterioration of the condition. Medicinal plants and their bioactive constituents are considered to be safer and more effective than synthetic medicines against various chronic diseases. Therefore, the use of natural products in the management of DN has been suggested. In this article, we review medicinal plants and their specific bioactive phytochemicals that regulate the various cellular processes involved in the initiation of DN. A wide range of literature on phytochemicals and medicinal plants that may ameliorate DN was explored from the online available English works in various electronic databases, including Embase, Google Scholar, PubMed, Scopus, and Science Direct.

RESULTS

Medicinal plants possess various bioactive constituents, which may slow or ameliorate the progression of DN and improve renal function through the targeting of multiple pathological causes via different pathways, including p38MAPK, JNK, ERK, TGF-β, RhoA, NF-κB, Wnt, JAK-STAT, AMPK, mTOR, Akt, and TXNIP. Depletion or inhibition of these accelerating factors may provide a significant treatment for DN.

CONCLUSION

Based on various experimental studies, traditional herbs and their bioactive constituents regulate the cellular processes involved in the initiation of DN owing to their significant pharmacological activities; however, the efficacy in animal models and humans has not yet been explored. Therefore, studies should be performed to evaluate the nephroprotective effects of medicinal plants in preclinical animal models and in humans.

Comparative pharmacokinetics of four active components on normal and diabetic rats after oral administration of Gandi capsules

The Gandi capsule, a famous traditional Chinese medicine (TCM), is a hospital preparation that has been widely used in China for decades for the treatment of diabetes.

Antidiabetic Potential of Monoterpenes: A Case of Small Molecules Punching above Their Weight

Monoterpenes belong to the terpenoids class of natural products and are bio-synthesized through the mevalonic acid pathway. Their small molecular weight coupled with high non-polar nature make them the most abundant components of essential oils which are often considered to have some general antioxidant and antimicrobial effects at fairly high concentrations. These compounds are however reported to have antidiabetic effects in recent years. Thanks to the ingenious biosynthetic machinery of nature, they also display a fair degree of structural complexity/diversity for further consideration in structure-activity studies. In the present communication, the merit of monoterpenes as antidiabetic agents is scrutinized by assessing recent in vitro and in vivo studies reported in the scientific literature. Both the aglycones and glycosides of these compounds of rather small structural size appear to display antidiabetic along with antiobesity and lipid lowering effects. The diversity of these effects vis-à-vis their structures and mechanisms of actions are discussed. Some key pharmacological targets include the insulin signaling pathways and/or the associated PI3K-AKT (protein kinase B), peroxisome proliferator activated receptor-γ (PPARγ), glucose transporter-4 (GLUT4) and adenosine monophosphate-activated protein kinase (AMPK) pathways; proinflammatory cytokines and the NF-κB pathway; glycogenolysis and gluconeogenesis in the liver; glucagon-like-1 receptor (GLP-1R); among others.

Variation of loganin content in Cornus officinalis fruits at different extraction conditions and maturation stages

Efficient preparation of loganin from Cornus officinalis fruits was investigated. First, effect of extraction conditions on loganin yield was measured. The loganin content in C. officinalis extract was greatly affected by ethanol concentration and extraction time whereas extraction temperature exerted relatively little effect. Response surface methodology with Box-Behnken design suggested optimized extraction condition for maximum loganin yield as ethanol concentration, 32.0%; temperature 46.2 °C and extraction time, 46.7 min, which yielded 10.4 μg loganin/mg dried fruit. Next, the effect of maturation stage of C. officinalis fruits on loganin content was investigated. The loganin content in the extract of C. officinalis fruits was decreased as the maturation process. The loganin content in the unripe fruits was 18.0 μg/mg extract whereas reduced to 13.3 μg/mg extract for ripe fruits. Taken together, our present study suggested the importance of extraction condition and maturation stages for efficient preparation of loganin from C. officinalis fruits.

Blocking Smad2 signalling with loganin attenuates SW10 cell cycle arrest induced by TNF-α

The activity of Schwann cells (SWCs) is very important in trauma-induced nerve repair, and tumour necrosis factor-α (TNF-α) produced during tissue injury inhibits the viability of SWCs, which delays the repair of peripheral nerves. Loganin is an iridoid glycoside that has been shown to alleviate a variety of cytotoxic effects. In the current study, we evaluated the potential efficacy and the mechanism of action of loganin in TNF-α-induced cytotoxicity in SW10 cells. The experimental results indicated that loganin blocked TNF-α-mediated Smad2 activation, downregulated the expression of the G1 phase cell cycle inhibitor p15IN4KB, and upregulated the expression of the G1 phase cell cycle activator cyclin D1-CDK4/6, which upregulated E2F-1-dependent survivin expression and relieved TNF-α-induced apoptosis in SW10 cells. The protective effect of loganin on SWCs has potential medicinal value in the promotion of peripheral nerve repair and is significant for studies in the field of tissue regeneration.

Iridoid glycoside from Cornus officinalis ameliorated diabetes mellitus-induced testicular damage in male rats: Involvement of suppression of the AGEs/RAGE/p38 MAPK signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis (CO) has been widely used as a traditional Chinese medicine for treating diabetes mellitus (DM) and its complications. Iridoid glycoside from C. officinalis (IGCO) can resist apoptosis, hyperglycemia, oxidation and so on. The aim of this study was to investigate the therapeutic effects of IGCO on DM-induced testicular damage through inhibition of the AGEs/RAGE/p38 MAPK signaling pathway.

MATERIALS AND METHODS

A DM model of male Wistar rats was induced with streptozotocin injection (30mg/kg, i.p.) and high-fat diet. The DM rats were administrated with IGCO at low and high doses (15 and 30mg/kg, p.o.) for 12 weeks. Testicular damage was evaluated by estimating relative testicular weights, testicular pathohistology, sperm count, live sperm rate, endogenous sex hormone level and activity of testicular marker enzymes. Besides, general diabetic symptoms, renal function, oxidative stress parameters and testicular apoptosis marker were also determined. Finally, the mechanism was explored based on the AGEs/RAGE/p38 MAPK pathway.

RESULTS

IGCO effectively mitigated the general symptoms of DM rats including weight loss, polydipsia, polyphagia, polyuria, elevated blood glucose level and low serum insulin level. Nourishing the kidney evidently, IGCO reduced serum creatinine, urea nitrogen and urine protein excretion, and also markedly protected against DM-induced testicular damage by increasing testis/body weight ratio and live sperm rate, improving the histomorphology of testes, upregulating testosterone, LH, FSH and GnRH levels and preventing the decrease of testicular marker enzymes LDH, ACP and γ-GT. Moreover, IGCO showed considerable anti-oxidative and anti-apoptotic effects, which downregulated the increase of ROS and MDA levels, restored SOD and CAT activities, and decreased spermatogenic cell apoptosis and Bax/Bcl-2 ratio. In the end, the increased AGEs, RAGE and p-p38 MAPK protein levels in DM rats were also reversed by IGCO significantly.

CONCLUSIONS

The kidney tonic IGCO well protected DM rats from testicular damage, which may be related to suppression of the AGEs-RAGE-p38 MAPK pathway.

Iridoids are natural glycation inhibitors

Glycation of amino acid residues in proteins leads to the eventual formation of advanced glycation end products (AGEs). AGE formation significantly influences human health and the aging process. AGE accumulation rates may be slowed by modifications to lifestyle or by pharmacological strategies. But the use of therapeutic drugs is not an appropriate means of controlling AGEs within the general population. However, phytochemical constituents in plant-based foods exhibit anti-glycation activities and may be more appropriate for general consumption. Among these phytochemicals are iridoids. The anti-AGE potential of iridoids has been demonstrated in vitro and in vivo, while also revealing possible mechanisms of action. Inclusion of iridoid food sources in the diet may be a useful component of strategies intended to mitigate AGE accumulation within the body.