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

Lipid-lowering effect and oral transport characteristics study of curculigoside

Introduction

The incidence of metabolic disorders during pregnancy is increasing year by year, with diseases including hypertension and hyperlipidemia. Statins are the primary drugs for treating hyperlipidemia or atherosclerosis, yet some patients remain unresponsive to them, and pregnant women are prohibited from taking statins. Curculigoside is the major biologically active natural product present in Curculigo orchioides.

Methods

In this study, A high-fat mice model was developed to study the lipid-lowering effect of curculigoside. Using intestinal Caco-2 cell monolayer, the curculigoside transport properties at two temperatures and possible transporters were systemically studied.

Results

Curculigoside at concentrations used during the experiments have no toxic effect to Caco-2 cells. The curculigoside transfer from the apical to the basolateral side was strongly influenced by temperature. P-glycoprotein, breast cancer resistance protein, and efflux transporters are crucial components of the human intestinal cell line Caco-2. The curculigoside can significantly affect the contents of total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol in mice.

Discussion

The transport properties and potential mechanism of curculigoside offer valuable insights for the design of development of hypolipidemic drugs like anti-atherosclerotic drugs and also be helpful to the further study of the pharmacological activity of curculigoside.

Empagliflozin protects against isoprenaline-induced fibrosis in rat heart through modulation of TGF-β/SMAD pathway

AIM

Cardiac fibrosis is characterized by excessive accumulation of fibrous tissue, particularly collagens, in the myocardium. Accumulated fibrous tissue renders myocardium stiffer and reduces its contractility. Empagliflozin is an oral hypoglycemic agent with extra-diabetic functional profile toward maintaining cardiac functions. The present study aimed to examine protective effect of empagliflozin against an in-vivo model of cardiac fibrosis induced by isoprenaline and targeting TGF-β/SMAD signaling as a possible pathway responsible for such effect.

MAIN METHODS

Sixty animals were divided into six groups; the first was normal, and the second was treated with isoprenaline only (5 mg/kg/day I.P.) as a control. The third received pirfenidone (500 mg/kg/day P.O.), and the remaining groups received graded doses (5, 10, 20 mg/kg respectively) of empagliflozin for 14 days before fibrosis induction by isoprenaline (5 mg/kg/day) for 30 days.

KEY FINDINGS

Isoprenaline increased cardiac enzymes, and cardiac tissues revealed elevated concentrations of transforming growth factor β (TGF-β1), monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor α (TNF-α), and c-jun N-terminal kinase (JNK) proteins. Expression of nuclear factor kappa B (NF-κB), alpha smooth muscle actin (α-SMA), collagens, suppressor of mothers against decapentaplegic (SMADs), connective tissue growth factor (CTGF), and fibronectin was upregulated. Empagliflozin improved the histological picture of heart tissue in comparison to fibrosis developed in controls, and protected against fibrosis through significant modulation of all mentioned parameters' concentrations and expressions.

SIGNIFICANCE

Empagliflozin demonstrated a promising protective approach against biological model of cardiac fibrosis through an anti-fibrotic effect through targeting TGF-β signaling pathways.

Natural Plant Extract - Loganin: A Hypothesis for Psoriasis Treatment Through Inhibiting Oxidative Stress and Equilibrating Immunity via Regulation of Macrophage Polarization

Psoriasis, a chronic immune-mediated inflammatory skin disease, influences approximately 2-3% of the world's population. At present, the etiology of psoriasis remains unclear and there is still no causal treatment available. Recent studies indicate that oxidative stress (OS) and T cells dysregulation may participate in the pathogenesis of psoriasis, among which M1-dominant macrophage polarization is a crucial contributor. Macrophages mainly polarize into two different subsets, ie, classically activated macrophage (M1) and alternatively activated macrophage (M2). M1 polarization tends to exacerbate psoriasis via producing substantial reactive oxygen species (ROS) and inflammatory mediators, to encourage OS invasion and T cells dysregulation. Thus, targeting M1 polarization can be a possible therapeutic alternative for psoriasis. Loganin, belonging to iridoid glycosides, is a pharmaceutically active ingredient originated from Cornus officinalis, exerting multiple biological activities, eg, immunomodulation, antioxidation, anti-inflammation, etc. More importantly, it could effectively suppress M1 polarization, thereby arresting OS aggression and T cells' dysregulation. Numerous studies have confirmed that loganin is quite reliable for diseases treatment via suppressing M1 polarization. Nevertheless, reports about loganin treating psoriasis have seldom appeared so far. Accordingly, we hold a hypothesis that loganin would availably manage psoriasis through preventing M1 polarization. Data from previous studies guarantee the potential of loganin in control of psoriasis.

Metabolic profile and potential mechanisms of Wendan decoction on coronary heart disease by ultra-high-performance quadrupole time of flight-mass spectrometry combined with network pharmacology analysis

Wendan decoction, a well-known classical traditional Chinese medicine prescription, has been widely used in the clinical application of coronary heart disease for thousands of years. However, due to a lack of research on the overall metabolism of Wendan decoction, the bioavailable components responsible for the therapeutic effects remain unclear, hindering the revelation of its mechanisms against coronary heart disease. Consequently, an efficient joint research pattern combined with characterization of the metabolic profile and network pharmacology analysis was proposed. As a result, a total of 172 Wendan decoction-related xenobiotics (57 prototypes and 115 metabolites) were detected based on the exploration of the typical metabolic pathways of representative pure compounds in vivo, describing their multi-component metabolic characteristics comprehensively. Subsequently, an integrated network of "herbs-bioavailable compounds-coronary heart disease targets-pathways-therapeutic effects" was constructed, and its seven compounds were finally screened out as the key components acting on five main targets of coronary heart disease. Overall, this work not only provided a crucial biological foundation for interpreting the effective components and action mechanisms of Wendan decoction on coronary heart disease but also showed a reference value for revealing the bioactive components of traditional Chinese medicine prescriptions.

Improved uptake and bioavailability of cinnamaldehyde via solid lipid nanoparticles for oral delivery

OBJECTIVE

The purpose of this experiment was to explore the effect of Solid lipid nanoparticles (SLNs) on improving the oral absorption and bioavailability of cinnamaldehyde (CA).

METHODS

CA-SLNs were prepared by high-pressure homogenization and characterized by particle size, entrapment efficiency, and morphology, thermal behavior and attenuated total reflection Fourier transform infrared (ATR-FTIR). In vitro characteristics of release, stability experiments, cytotoxicity, uptake and transport across Caco-2 cell monolayer of CA-SLNs were studied as well. In addition, CA-SLNs underwent pharmacokinetic and gastrointestinal mucosal irritation studies in rats.

RESULTS

CA-SLNs exhibited a spherical shape with a particle size of 44.57 ± 0.27 nm, zeta potential of -27.66 ± 1.9 mV and entrapment efficiency of 83.63% ± 2.16%. Differential scanning calorimetry (DSC) and ATR-FTIR confirmed that CA was well encapsulated. In vitro release of CA-SLNs displayed that most of the drug (90.77% ± 5%) was released in the phosphate buffer, and only a small amount of drug (18.55% ± 5%) was released in the HCl buffer. CA-SLNs were taken up by an energy-dependent, endocytic mechanism mediated by caveolae mediated endocytosis across Caco-2 cells. The CA permeation through Caco-2 cell was facilitated by CA-SLNs. The outcome of the gastrointestinal irritation test demonstrated that CA-SLNs had no irritation to the rats' intestines. Compared with CA dispersions, incorporation of SLNs increased the oral bioavailability of CA more than 1.69-fold.

CONCLUSIONS

It was concluded that CA-SLNs improved the absorption across Caco-2 cell model and improved the oral administration bioavailability of CA in rats.

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.

Interplay between PI3K/AKT pathway and heart disorders

The PI3K/AKT signaling has crucial role in the regulation of numerous physiological functions through activation of downstream effectors and modulation of cell cycle transition, growth and proliferation. This pathway participates in the pathogenesis of several human disorders such as heart diseases through regulation of size and survival of cardiomyocytes, angiogenic processes as well as inflammatory responses. Moreover, PI3K/AKT pathway participates in the process of myocardial injury induced by a number of substances such as H₂O₂, Mercury, lipopolysaccharides, adriamycin, doxorubicin and epirubicin. In this review, we describe the contribution of this pathway in the pathoetiology of myocardial ischemia/reperfusion injury and myocardial infarction, heart failure, cardiac hypertrophy, cardiomyopathy and toxins-induced cardiac injury.

Xinglou Chengqi Decoction improves neurological function in experimental stroke mice as evidenced by gut microbiota analysis and network pharmacology

The current study was designed to explore the brain protection mechanism of Xinglou Chengqi Decoction (XCD) based on gut microbiota analysis and network pharmacology. A transient middle cerebral artery occlusion (MCAO) model of mice was established, followed by behavioral evaluation, TTC and TUNEL staining. Additionally, to investigate the effects of gut microbiota on neurological function after stroke, C57BL/6 mice were treated with anti-biotic cocktails 14 days prior to ischemic stroke (IS) to deplete the gut microbiota. High-throughput 16S rDNA gene sequencing, metabonomics technique, and flow multifactor technology were used to analyze bacterial communities, SCFAs and inflammatory cytokines respectively. Finally, as a supplement, network pharmacology and molecular docking were applied to fully explore the multicomponent-multitarget-multichannel mechanism of XCD in treating IS, implicated in ADME screening, target identification, network analysis, functional annotation, and pathway enrichment analysis. We found that XCD effectively improved neurological function, relieved cerebral infarction and decreased the neuronal apoptosis. Moreover, XCD promoted the release of anti-inflammatory factor like IL-10, while down-regulating pro-inflammatory factors such as TNF-α, IL-17A, and IL-22. Furthermore, XCD significantly increased the levels of short chain fatty acids (SCFAs), especially butyric acid. The mechanism might be related to the regulation of SCFAs-producing bacteria like Verrucomicrobia and Akkermansia, and bacteria that regulate inflammation like Paraprevotella, Roseburia, Streptophyta and Enterococcu. Finally, in the network pharmacological analysis, 51 active compounds in XCD and 44 intersection targets of IS and XCD were selected. As a validation, components in XCD docked well with key targets. It was obviously that biological processes were mainly involved in the regulation of apoptotic process, inflammatory response, response to fatty acid, and regulation of establishment of endothelial barrier in GO enrichment. XCD can improve neurological function in experimental stroke mice, partly due to the regulation of gut microbiota. Besises, XCD has the characteristic of "multi-component, multi-target and multi-channel" in the treatment of IS revealed by network pharmacology and molecular docking.

Targeting JAK/STAT signaling pathways in treatment of inflammatory bowel disease

Janus kinase/signal transduction and transcriptional activator (JAK/STAT) signaling pathway is a transport hub for cytokine secretion and exerts its effects. The activation of JAK/STAT signaling pathway is essential for the regulation of inflammatory responses. Inappropriate activation or deletion of JAK/STAT signaling pathway is the initiator of the inflammatory response. JAK/STAT signaling pathway has been demonstrated to be involved in the process of innate and adaptive immune response to inflammatory bowel disease (IBD). In this review, we discuss the role of the JAK/STAT signaling pathway in the regulation of different cells in IBD, as well as new findings on the involvement of the JAK/STAT signaling pathway in the regulation of the intestinal immune response. The current status of JAK inhibitors in the treatment of IBD is summarized as well. This review highlights natural remedies that can serve as potential JAK inhibitors. These phytochemicals may be useful in the identification of precursor compounds in the process of designing and developing novel JAK inhibitors.

In Silico Molecular Docking and Interaction Analysis of Traditional Chinese Medicines Against SARS-CoV-2 Receptor

The novel coronavirus, 2019-nCoV, has led to a major pandemic in 2020 and is responsible for more than 2.9 million officially recorded deaths worldwide. As well as synthetic anti-viral drugs, there is also a need to explore natural herbal remedies. The Traditional Chinese Medicines (TCMs) system has been used for thousands of years for the prevention, diagnosis, and treatment of several chronic diseases. In this paper, we performed an in silico molecular docking and interaction analysis of TCMs against SARS-CoV-2 receptor RNA-dependent RNA polymerase (RdRp). We obtained the 5 most effective plant compounds which had a better binding affinity towards the target receptor protein. These compounds areforsythoside A, rutin, ginkgolide C, icariside II, and nolinospiroside E. The top-ranked compound, based on docking score, was nolinospiroside, a glycoside found in Ophiopogon japonicas that has antioxidant properties. Protein-ligand interaction analysis discerned that nolinospiroside formed a strong bond between ARG 349 of the protein receptor and the carboxylate group of the ligand, forming a stable complex. Hence, nolinospiroside could be deployed as a lead compound against SARS-CoV-2 infection that can be further investigated for its potential benefits in curbing the viral infection.

Traditional uses, ten-years research progress on phytochemistry and pharmacology, and clinical studies of the genus Scutellaria

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellaria (Lamiaceae), which includes approximately 360-469 accepted species, is widespread in Europe, North America, East Asia, and South America. Several species have a long history being used as traditional medicines to treat respiratory, peptic, neurological, and hepatic and gall diseases. The phytochemistry and pharmacology of the genus Scutellaria have been developed dramatically in the past ten years, and the traditional uses and clinical studies of the genus have not been systematically summarized. Therefore, it is especially valuable to review the current state of knowledge to provide a basis for further exploration of its medicinal potential.

AIM OF THE REVIEW

The review aims to provide updated information on the ethnopharmacology, the ten-year research progress of phytochemistry and pharmacology, and clinical studies of Scutellaria and to explore the potential medicinal values and further studies of Scutellaria.

MATERIALS AND METHODS

This review is based on published studies and books from the library and electronic sources, including SciFinder, Scopus, PubMed, Web of Science, Baidu Scholar, CNKI, the online ethnobotanical database, and ethnobotanical monographs. This literature is related to ethnopharmacology, the ten-year research progress on the phytochemistry and pharmacology, and clinical studies of Scutellaria.

RESULTS

A total of 50 species, 5 subspecies and 17 varieties of the genus Scutellaria are used as traditional medicine with various biological activities. In the past ten years, 208 chemical constituents have been identified from 16 species and 1 variety of the genus Scutellaria, such as neo-clerodane diterpenoids, sesterterpenoids, terpenoids, flavonoids. Pharmacological research has demonstrated that the extracts and compounds identified from this genus exhibit extensive biological activities, including anticancer, antioxidant, anti-inflammatory, antiviral and antibacterial activities, effects on cardiovascular, cerebrovascular diseases as well as hepatoprotective and neuroprotective effects. The species S. baicalensis, S. barbata, and S. lateriflora and the main compounds baicalein, baicalin and wogonin are involved in clinical trials, which point the way for us to conduct further studies, such as study on the anticancer, antihypertensive, anti-infective, anti-inflammatory, neuroprotective and other effects of Scutellaria.

CONCLUSIONS

The species included in the genus Scutellaria can be used to treat cancer, infection, hepatic disorders, cardiovascular and cerebrovascular diseases, neurodegenerative diseases, and other diseases. Some indications in traditional medicines have been confirmed by modern pharmacological studies, such as anticancer, anti-inflammatory, anti-infective activity, and hepatoprotective and neuroprotective effects. The available literature indicated that most of the bioactivities could be attributed to flavonoids and neo-clerodane diterpenoids. Although there are some uses of Scutellaria in clinical practice, the existing research on this genus is still limited. In order to expand the development of medicinal resources of Scutellaria, the already studied species in this genus are recommended for more comprehensive investigation on their active substances, pharmacological mechanisms, quality control, clinical use and new drug research. Additionally, it is necessary to study species that their chemical composition or pharmacological activity have not yet been investigated, especially those used in folk medicine.

Loganetin and 5-fluorouracil synergistically inhibit the carcinogenesis of gastric cancer cells via down-regulation of the Wnt/β-catenin pathway

Although most gastrointestinal tumours are sensitive to 5-fluorouracil (5FU), drug resistance is commonly occurred after 5FU therapy in gastric cancer (GC). Loganetin is the primary active compound in Cornus officinali. However, the synergetic effects of loganetin and 5FU on GC remain unknown. Here, we investigated the synergetic effects and the underlying mechanism of loganetin and 5FU on proliferation, stem-like properties, migration, and invasion of GC both in vitro and in vivo. We found that loganetin alone inhibited the proliferation, stem-like properties, migration and invasion of GC cells in vitro. Importantly, the loganetin remarkably enhanced the anti-cancer effect of 5FU on GC cells and the Wnt/β-catenin pathway might be involved in this process. Animal experiments further confirmed the synergistic effects of 5FU and loganetin on inhibiting cell growth and metastasis of GC. These results suggested that loganetin could synergistically increase the effect of 5FU against GC, which sheds light on effective combinational drug strategies for GC treatment.

Characterization of the intestinal absorption of morroniside from Cornus officinalis Sieb. et Zucc via a Caco-2 cell monolayer model

Morroniside is a biologically active polyphenol found in Cornus officinalis Sieb. et Zucc (CO) that exhibits a broad spectrum of pharmacological activities, such as protecting nerves, and preventing diabetic liver damage and renal damage. However, little data are available regarding the mechanism of its intestinal absorption. Here, an in vitro human intestinal epithelial cell model of cultured Caco-2 cells was applied to study the absorption and transport of morroniside. The effects of donor concentration, pH and inhibitors were investigated. The bidirectional permeability of morroniside from the apical (AP) to the basolateral (BL) side and in the reverse direction was studied. When administered at three tested concentrations (5, 25 and 100 μM), the apparent permeability coefficient (Papp) values in the AP-to-BL direction ranged from 1.59 × 10-6 to 2.66 × 10-6 cm/s. In the reverse direction, BL-to-AP, the value was ranged from 2.67 × 10-6 to 4.10 × 10-6 cm/s. The data indicated that morroniside transport was pH-dependent. The permeability of morroniside was affected by treatment with various inhibitors, such as multidrug resistance protein inhibitors MK571 and indomethacin, as well as the breast cancer resistance protein inhibitor apigenin. The mechanisms of the intestinal absorption of morroniside may involve multiple transport pathways, such as the passive diffusion and efflux protein-mediated active transport especially involving multidrug resistance protein 2 and breast cancer resistance protein. After the addition of CO, the Papp values in the AP-to-BL direction increased significantly, therefore, it can be assumed that some ingredients in the CO promote morroniside absorption in the small intestine.

6-Gingerol ameliorates sepsis-induced liver injury through the Nrf2 pathway

Sepsis-induced liver injury is very common in intensive care units. Here, we investigated the effects of 6-gingerol on sepsis-induced liver injury and the role of the Nrf2 pathway in this process. 6-Gingerol is the principal ingredient of ginger that exerts anti-inflammatory and antioxidant effects. Using cecal ligation and puncture (CLP) to induce polymicrobial sepsis and related liver injury, we found that mice pre-treated with 6-Gingerol showed less incidences of severe liver inflammation and death than untreated CLP groups. 6-Gingerol administration also inhibited the expression of pyroptosis-related proteins, including NOD-like receptor protein 3 (NLRP3), IL-1β, and caspase-1. Consistent with these findings, 6-gingerol reduced the effects of pyroptosis induced by lipopolysaccharide (LPS) and adenosine 5'-triphosphate (ATP) in RAW 264.7 cells, as evidenced by IL-1β and caspase-1 protein levels in the supernatant and propidium iodide (PI) staining. 6-Gingerol was shown to activate the Nrf2 pathway in vivo and in vitro. Notably, Nrf2 siRNA transfection nullified the inhibitory effects of 6-gingerol on pyroptosis in vitro. In summary, these findings suggested that 6-gingerol alleviated sepsis-induced liver injury by inhibiting pyroptosis through the Nrf2 pathway.