Scopoletin: a review of its pharmacology, pharmacokinetics, and toxicity

Scopoletin is a coumarin synthesized by diverse medicinal and edible plants, which plays a vital role as a therapeutic and chemopreventive agent in the treatment of a variety of diseases. In this review, an overview of the pharmacology, pharmacokinetics, and toxicity of scopoletin is provided. In addition, the prospects and outlook for future studies are appraised. Scopoletin is indicated to have antimicrobial, anticancer, anti-inflammation, anti-angiogenesis, anti-oxidation, antidiabetic, antihypertensive, hepatoprotective, and neuroprotective properties and immunomodulatory effects in both in vitro and in vivo experimental trials. In addition, it is an inhibitor of various enzymes, including choline acetyltransferase, acetylcholinesterase, and monoamine oxidase. Pharmacokinetic studies have demonstrated the low bioavailability, rapid absorption, and extensive metabolism of scopoletin. These properties may be associated with its poor solubility in aqueous media. In addition, toxicity research indicates the non-toxicity of scopoletin to most cell types tested to date, suggesting that scopoletin will neither induce treatment-associated mortality nor abnormal performance with the test dose. Considering its favorable pharmacological activities, scopoletin has the potential to act as a drug candidate in the treatment of cancer, liver disease, diabetes, neurodegenerative disease, and mental disorders. In view of its merits and limitations, scopoletin is a suitable lead compound for the development of new, efficient, and low-toxicity derivatives. Additional studies are needed to explore its molecular mechanisms and targets, verify its toxicity, and promote its oral bioavailability.

Proposed mechanisms of action of herbal drugs and their biologically active constituents in the treatment of coughs: an overview

Various medicinal plants find their use in cough treatment, based on traditions and long-term experience. Pharmacological principles of their action, however, are much less known. Herbal drugs usually contain a mixture of potentially active compounds, which can manifest diverse effects. Expectorant or antitussive effects, which can be accompanied by others, such as anti-inflammatory or antibacterial, are probably the most important in the treatment of coughs. The aim of this review is to summarize the current state of knowledge of the effects of medicinal plants or their constituents on cough, based on reliable pharmacological studies. First, a comprehensive description of each effect is provided in order to explain the possible mechanism of action in detail. Next, the results related to individual plants and substances are summarized and critically discussed based on pharmacological in vivo and in vitro investigation.

Secondary Metabolites Isolated from Artemisia afra and Artemisia annua and Their Anti-Malarial, Anti-Inflammatory and Immunomodulating Properties-Pharmacokinetics and Pharmacodynamics: A Review

There are over 500 species of the genus Artemisia in the Asteraceae family distributed over the globe, with varying potentials to treat different ailments. Following the isolation of artemisinin (a potent anti-malarial compound with a sesquiterpene backbone) from Artemisia annua, the phytochemical composition of this species has been of interest over recent decades. Additionally, the number of phytochemical investigations of other species, including those of Artemisia afra in a search for new molecules with pharmacological potentials, has increased in recent years. This has led to the isolation of several compounds from both species, including a majority of monoterpenes, sesquiterpenes, and polyphenols with varying pharmacological activities. This review aims to discuss the most important compounds present in both plant species with anti-malarial properties, anti-inflammatory potentials, and immunomodulating properties, with an emphasis on their pharmacokinetics and pharmacodynamics properties. Additionally, the toxicity of both plants and their anti-malaria properties, including those of other species in the genus Artemisia, is discussed. As such, data were collected via a thorough literature search in web databases, such as ResearchGate, ScienceDirect, Google scholar, PubMed, Phytochemical and Ethnobotanical databases, up to 2022. A distinction was made between compounds involved in a direct anti-plasmodial activity and those expressing anti-inflammatory and immunomodulating activities or anti-fever properties. For pharmacokinetics activities, a distinction was made between compounds influencing bioavailability (CYP effect or P-Glycoprotein effect) and those affecting the stability of pharmacodynamic active components.

Chemical composition-based characterization of the anti-allergic effect of Guominkang Formula on IgE-mediated mast cells activation and passive cutaneous anaphylaxis

Guominkang (GMK), a Chinese medicine formula, has been used to treat allergic diseases in clinical settings for many years. To evaluate the antiallergic effect and molecular mechanism of action of GMK extract, RBL-2H3 cell models and passive cutaneous anaphylaxis (PCA) mouse models were established. High performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) analyses were performed to characterize the chemical composition of GMK. A total of 94 compounds were identified or tentatively identified from GMK. Three of them, emodin, ursolic acid, and hamaudol, were identified for the first time as potential active compounds in GMK, since they inhibited the degranulation of mast cells. The anti-allergic effect of hamaudol was the first to be discovered. GMK could markedly mitigate the shade of Evans Blue extravasation and ear incrassation in PCA mouse models. Additionally, GMK significantly inhibited the degranulation of mast cells, suppressed mast cell degranulation by reducing Ca²⁺ influx and the levels of TNF-α, IL-4, and histamine, and markedly inhibited the phosphorylation of Lyn, Syk, PLCγ1, IκBα, and NF-κB p65. Molecular docking results indicated that hamaudol and emodin had strong interaction with FcɛRI and NF-κB related proteins, while ursolic acid only interacted with NF-κB associated proteins. These results suggest GMK suppresses the activation of MCs both in vivo and in vitro. The underlying mechanism of its anti-allergic activity is associated with the inhibition of FcɛRI and NF-κB activation.

The ethnopharmacology, phytochemistry, pharmacology and toxicology of the genus Erycibe (Convolvulaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Erycibe belongs to the Convolvulaceae family that contains approximately 70 species mainly distributed from tropical and subtropical Asia to north of Australia. Several Erycibe species are traditionally used in folk medicine for the treatment of various ailments, including rheumatic arthralgia, primary glaucoma, hepatopathies, and infectious and malignant diseases.

AIM OF THE REVIEW

This review aims to summarize comprehensive and updated information on traditional medicinal uses, phytochemistry, pharmacology, and toxicology of Erycibe species to provide a reference for the further research and application of the Erycibe genus.

MATERIALS AND METHODS

The scientific and extensive literatures between 1975 and 2020 were systematically gathered from scientific databases such as SciFinder Scholar, Science Direct, Web of Science, PubMed, Google Scholar, Scopus, Springer Link and China National Knowledge Infrastructure (CNKI), as well as Chinese herbal classic books, PhD and MSc theses, and several official websites.

RESULTS

Erycibe species have been used for the treatment of various rheumatoid diseases, glaucoma, a variety of hepatic diseases, infectious diseases and various malignancies in the traditional and local medicine. Since the 1970s, 153 compounds, including coumarins, quinic acid derivatives, flavonoids, alkaloids, lignans, and others have been isolated from five species of the Erycibe genus. Pharmacological studies have shown that these extracts and compounds from the Erycibe genus have extensive activities consistent with the traditional and local applications, such as anti-glaucoma, anti-arthritic, hepatoprotective and anti-cancer activities, as well as anti-inflammatory, anti-respiratory syncytial virus (RSV), and neuroprotective properties.

CONCLUSIONS

Although there are extensive data on the genus Erycibe, certain specific gaps still exist. For herbal preparations containing Erycibe species, clinical toxicological investigation is required for the safety of these herbal preparation therapies, as well as further investigations on pharmacokinetics and bioavailability for guideline for clinical application. Furthermore, more detailed pharmacological, toxicological and clinical researches are needed to assess the alternatives to Erycibe species. Systematic and comprehensive pre-clinical studies are similarly required to estimate the possibility of extracts and compounds from the genus Erycibe with bioactivity developing into new drugs.

Degraded Porphyra haitanensis sulfated polysaccharide relieves ovalbumin-induced food allergic response by restoring the balance of T helper cell differentiation

We previously described that Porphyra haitanensis sulfated polysaccharide (PHSP) maintains the balance of pro-inflammation and immunosuppression. However, it is unclear whether degraded PHSP (DPHSP) still shows the immunomodulatory activity. Here, we degraded PHSP by four different methods alone or combined in pairs, and the results showed that the molecular weight and viscosity of DPHSP were significantly decreased, while the main chemical bonds and functional structure were consistent with those of PHSP. We then investigated the immunomodulatory function of DPHSP in vitro and in vivo. Actually, DPHSP enhances the inhibitory effects on mast cell activation and improves the suppression activity of PHSP on the food anaphylactic response. In an ovalbumin-induced food allergy mouse model, the production of allergic mediators and cytokines (interleukin-4 and 13, and interferon-γ) was inhibited by DPHSP. Meanwhile, DPHSP had a stronger ability to up-regulate the differentiation of regulatory T (Treg) cells and its related cytokines. These results suggested that DPHSP showed a better anti-food allergic ability than PHSP by regulating T helper cell balance and promoting Treg cell differentiation, which indicates that DPHSP is a novel potential nutrient component against food allergy.

Identification of Chemical Compounds from Artemisia gmelinii using UPLC-QTOF-MS/MS and their Regulatory Effects on Immune Responses in DSS-Induced Colitis Mice

Artemisia gmelinii Web. ex Stechm. (AG), a popular medicinal herb in Asia, has been used as a common food ingredient in Korea and is traditionally known for its anti-inflammatory properties. Therefore, in this study, we aimed to investigate whether AG relieves IBD, a classic chronic inflammatory disease of the gastrointestinal tract. We identified 35 chemical compounds in AG ethanol extract using ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry. In mice with DSS-induced IBD, AG administration attenuated the disease activity index and the serum and colonic levels of inflammatory cytokines and chemokines. AG treatment decreased nuclear factor-[Formula: see text]B (NF-[Formula: see text]B) signaling, a key mediator of inflammation, in the mouse colons. Additionally, AG extract enhanced immune responses in lymphoid tissues such as spleen and Peyer's patches. Thus, AG consumption potently ameliorated IBD symptoms and improved immune signaling in lymphoid tissues.

Artemisia scoparia and Metabolic Health: Untapped Potential of an Ancient Remedy for Modern Use

Botanicals have a long history of medicinal use for a multitude of ailments, and many modern pharmaceuticals were originally isolated from plants or derived from phytochemicals. Among these, artemisinin, first isolated from Artemisia annua, is the foundation for standard anti-malarial therapies. Plants of the genus Artemisia are among the most common herbal remedies across Asia and Central Europe. The species Artemisia scoparia (SCOPA) is widely used in traditional folk medicine for various liver diseases and inflammatory conditions, as well as for infections, fever, pain, cancer, and diabetes. Modern in vivo and in vitro studies have now investigated SCOPA's effects on these pathologies and its ability to mitigate hepatotoxicity, oxidative stress, obesity, diabetes, and other disease states. This review focuses on the effects of SCOPA that are particularly relevant to metabolic health. Indeed, in recent years, an ethanolic extract of SCOPA has been shown to enhance differentiation of cultured adipocytes and to share some properties of thiazolidinediones (TZDs), a class of insulin-sensitizing agonists of the adipogenic transcription factor PPARγ. In a mouse model of diet-induced obesity, SCOPA diet supplementation lowered fasting insulin and glucose levels, while inducing metabolically favorable changes in adipose tissue and liver. These observations are consistent with many lines of evidence from various tissues and cell types known to contribute to metabolic homeostasis, including immune cells, hepatocytes, and pancreatic beta-cells. Compounds belonging to several classes of phytochemicals have been implicated in these effects, and we provide an overview of these bioactives. The ongoing global epidemics of obesity and metabolic disease clearly require novel therapeutic approaches. While the mechanisms involved in SCOPA's effects on metabolic, anti-inflammatory, and oxidative stress pathways are not fully characterized, current data support further investigation of this plant and its bioactives as potential therapeutic agents in obesity-related metabolic dysfunction and many other conditions.

Citrus flavonoids suppress IL-5 and ROS through distinct pathways in PMA/ionomycin-induced EL-4 cells

Interleukin-5 (IL-5) strongly initiates the asthmatic inflammatory response, which affects 300 million patients with asthma annually worldwide, through oxidative stress generation. Citrus flavonoids have beneficial properties, such as anti-inflammatory and antioxidant properties, but the precise molecular mechanism of the inhibition of the asthmatic inflammatory response is still unclear. This study aimed to investigate the underlying mechanisms of ROS and IL-5 reduction with citrus flavonoid treatment in PMA/ionomycin-induced EL-4 cells. Our results showed that hesperetin and gardenin A dramatically suppressed ROS and IL-5 production through distinct pathways. Interestingly, hesperidin induced HO-1 expression through the transcription factor Nrf2 coupled with the PI3K/AKT or ERK/JNK signaling pathway, consequently downregulating NFAT activity and IL-5 secretion. Likewise, gardenin A induced HO-1 expression and subsequently suppressed IL-5 production by reducing NFAT activity and upregulating PPARγ in EL-4 cells, suggesting that inducing HO-1 expression may inhibit asthmatic inflammation. Altogether, hesperidin and gardenin A have great potential for regulating the asthma-associated immune responses through antioxidant properties.

Scopoletin Stimulates Melanogenesis via cAMP/PKA Pathway and Partially p38 Activation

Scopoletin was recently shown to stimulate melanogenesis through cAMP-response element-binding protein (CREB) phosphorylation. In this study, we investigated the molecular events of melanogenesis-induced by scopoletin. After exposure to scopoletin, the protein levels of tyrosinase and tyrosianse related protein-1 (TRP-1) were significantly increased in B16F10 cells. The mRNA levels of tyrosinase and microphthalmia-associated transcription factor (MITF) were also enhanced by scopoletin. cAMP production and phosphorylation of p38 mitogen-activated protein kinase (MAPK) were increased by scopoletin treatment. Scopoletin-mediated increase of intracellular melanin and tyrosinase expression were significantly attenuated by protein kinase A (PKA) inhibitors (H-89 and KT5720), while a protein kinase C (PKC) inhibitor (Ro-32-0432) had no effect and a p38 MAPK inhibitor (SB203580) partially blocked the scopoletin-induced intracellular melanin and tyrosinase expression. Moreover, scopoletin synergistically with cell-permeable cAMP analog (dibutyryl cAMP) significantly induced tyrosinase activity and melanin content in B16F10 cells. The silencing of p38 MAPK by small interfering RNA (siRNA) decreased the scopoletin-induced tyrosinase expression in B16F10 cells. These results suggest that scopoletin could induce melanin synthesis through the cAMP/PKA pathway and partially p38 MAPK activation in B16F10 cells.

Protein kinase C (PKC) isoforms in cancer, tumor promotion and tumor suppression

The AGC family of serine/threonine kinases (PKA, PKG, PKC) includes more than 60 members that are critical regulators of numerous cellular functions, including cell cycle and differentiation, morphogenesis, and cell survival and death. Mutation and/or dysregulation of AGC kinases can lead to malignant cell transformation and contribute to the pathogenesis of many human diseases. Members of one subgroup of AGC kinases, the protein kinase C (PKC), have been singled out as critical players in carcinogenesis, following their identification as the intracellular receptors of phorbol esters, which exhibit tumor-promoting activities. This observation attracted the attention of researchers worldwide and led to intense investigations on the role of PKC in cell transformation and the potential use of PKC as therapeutic drug targets in cancer diseases. Studies demonstrated that many cancers had altered expression and/or mutation of specific PKC genes. However, the causal relationships between the changes in PKC gene expression and/or mutation and the direct cause of cancer remain elusive. Independent studies in normal cells demonstrated that activation of PKC is essential for the induction of cell activation and proliferation, differentiation, motility, and survival. Based on these observations and the general assumption that PKC isoforms play a positive role in cell transformation and/or cancer progression, many PKC inhibitors have entered clinical trials but the numerous attempts to target PKC in cancer has so far yielded only very limited success. More recent studies demonstrated that PKC function as tumor suppressors, and suggested that future clinical efforts should focus on restoring, rather than inhibiting, PKC activity. The present manuscript provides some historical perspectives on the tumor promoting function of PKC, reviewing some of the observations linking PKC to cancer progression, and discusses the role of PKC in the pathogenesis of cancer diseases and its potential usage as a therapeutic target.

Systemic Administration of Proteoglycan Protects BALB/c Retired Breeder Mice from Experimental Arthritis

This study was undertaken to evaluate the prophylactic potential of proteoglycan (PG) administration in experimental arthritis. Female BALB/c retired breeder mice received two (2xPG50 and 2xPG100 groups) or three (3xPG50 group) intraperitoneal doses of bovine PG (50 μg or 100 μg) every three days. A week later the animals were submitted to arthritis induction by immunization with three i.p. doses of bovine PG associated with dimethyldioctadecylammonium bromide adjuvant at intervals of 21 days. Disease severity was daily assessed after the third dose by score evaluation. The 3xPG50 group showed significant reduction in prevalence and clinical scores. This protective effect was associated with lower production of IFN-γ and IL-17 and increased production of IL-5 and IL-10 by spleen cells restimulated in vitro with PG. Even though previous PG administration restrained dendritic cells maturation this procedure did not alter the frequency of regulatory Foxp3⁺ T cells. Lower TNF-α and IL-6 levels and higher expression of ROR-γ and GATA-3 were detected in the paws of protected animals. A delayed-type hypersensitivity reaction confirmed specific tolerance induction. Taken together, these results indicate that previous PG inoculation determines a specific tolerogenic effect that is able to decrease severity of subsequently induced arthritis.

The effect of 4α,5α-epoxy-10α,14-dihydro-inuviscolide, a novel immunosuppressant isolated from Carpesium abrotanoides, on the cytokine profile in vitro and in vivo

The plant Carpesium abrotanoides (CA) is used in Asian herbal medicines as an insecticide and to treat bruises. However, the effect of single compounds from CA blooms and the mechanism of its immunosuppressive effect remain poorly understood. The aim of this study was to investigate the mechanism of the immunosuppressive effect in the three kinds of immune cells, and the immunosuppressive effect of CA bloom extract (CAE) in acute inflammation models (LPS and ConA-induced inflammation). Interleukin-6, IL-4, IL-13, IFNγ, and IL-10-but not TNFα-were significantly reduced in a dose-dependent manner by 4α,5α-epoxy-10α,14-dihydro-inuviscolide (INV). Furthermore, INV inhibited NF-κB transcriptional activation and IL-10 promoter activity in the same manner as for Bay11. Meanwhile, treatment with dexamethasone reduced the levels of IFNγ, but not IL-10, and resulted in no change in NF-κB transcriptional activation or the IL-10 promoter. INV did not affect PMA-induced IκB kinase complex phosphorylation, IκB degradation, or MAPK and the nuclear translocation of p65, as with DEX. The in vivo, CAE has an immunosuppressive effect on the LPS-induced inflammation response model by inhibiting the plasma level of IFNγ and IL-6 levels. CAE treatment also tends to attenuate the plasma level of IFNγ, IL-4, and IL-6 in ConA-induced inflammation. These findings indicate that INV causes the reduction of the cytokine profile by blocking the NF-κB transcription factor activation and the molecular mechanism by which INV operates could provide new insights into the unique mechanisms responsible for NF-κB inhibition, in contrast to established immunosuppressants, as a therapeutic agent for immunopathological treatment.

Nymphaea rubra ameliorates TNF-α-induced insulin resistance via suppression of c-Jun NH2-terminal kinase and nuclear factor-κB in the rat skeletal muscle cells

In this work, we demonstrated insulin signaling and the anti-inflammatory effects by the chloroform fraction of ethanolic extract of Nymphaea rubra flowers in TNF-α-induced insulin resistance in the rat skeletal muscle cell line (L6 myotubes) to dissect out its anti-hyperglycemic mechanism. N. rubra enhances the GLUT4-mediated glucose transport in a dose dependent manner and also increases the tyrosine phosphorylation of both IR-β and IRS-1, and the IRS-1 associated PI-3 kinase activity in TNF-α-treated L6 myotubes. Moreover, N. rubra decreases Ser(307) phosphorylation of IRS-1 by the suppression of JNK and NF-κB activation. In conclusion, N. rubra reverses the insulin resistance by the inhibition of c-Jun NH2-Terminal Kinase and Nuclear-κB.

Scopoletin suppresses IL-6 production from fibroblast-like synoviocytes of adjuvant arthritis rats induced by IL-1β stimulation

Scopoletin, a coumarin compound naturally occurring in many medicinal plants, has previously been demonstrated to ameliorate synovial inflammation and destruction of cartilage and bone in adjuvant arthritis (AA) rats. As interleukin (IL)-6 is critically involved in the initiation and development of rheumatoid arthritis (RA), the present study was performed to investigate the effect of scopoletin on IL-6 production from fibroblast-like synoviocytes (FLS) to get insight into its anti-RA mechanisms. FLS were isolated from synovial membrane tissues of AA rats, and stimulated with IL-1β (10 ng/mL). Scopoletin, at concentrations of 15, 30, and 60 μM, was shown to only moderately inhibit FLS proliferation, but dramatically reduce IL-6 production at both mRNA and protein levels. It also inhibited the phosphorylation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK), protein kinase C (PKC) and cAMP response element binding protein (CREB). These findings suggest that scopoletin exerts anti-RA action probably through suppressing IL-6 production from FLS via MAPK/PKC/CREB pathways.

Antiatopic Dermatitis Effect of Artemisia iwayomogi in Dust Mice Extract-Sensitized Nc/Nga Mice

Aims. Artemisia iwayomogi (AI) has been used for fever reduction, diuresis, and hepatoprotection in Korea. The present study was performed to evaluate the anti-inflammatory and antiatopic dermatitis effects of AI using both in vitro and in vivo systems. Methods. The compositions in AI were analyzed by HPLC. To determine the anti-inflammatory effects of AI, the production of nitric oxide (NO) was measured in lipopolysaccharide treated RAW264.7 cells. Histamine levels were assayed to evaluate the antiallergic effects on MC/9 cells stimulated with phorbol-12 myristate 13-acetate and A23187. Finally, AI (10 mg/mouse/day) was topically applied onto the backs and ears of Dermatophagoides farinae-sensitized Nc/Nga mice for four weeks. Results. Isochlorogenic acid A (20.63 ± 0.26 mg/g), chlorogenic acid (9.04 ± 0.08 mg/g), and scopoletin (8.23 ± 0.01 mg/g) were among the major components of AI. AI inhibited the NO and histamine productions in RAW264.7 and MC/9 cells, respectively. In the mice, the topical application of AI reduced the dermatitis scores in the dorsal skin and ears and reduced the plasma levels of IgE. Conclusions. These results suggest that AI might be explored as a potential therapeutic agent to treat AD, and that the analytic method using HPLC will facilitate the development of quality control for AI.

Antiallergic asthma properties of brazilin through inhibition of TH2 responses in T cells and in a murine model of asthma

This study aimed to determine whether brazilin exhibits anti-inflammatory effects that inhibit T helper cell type II (T(H)2) responses and whether it suppresses allergic inflammation reactions in a murine model of asthma. We found that brazilin inhibited the mRNA and protein expression of interleukin (IL)-4 and IL-5 induced by phorbol myristate acetate (PMA) and cAMP in EL-4 T cells in a dose-dependent manner. Following the intratracheal instillation of brazilin in ovalbumin (OVA)-immunized mice, we found that brazilin-treated mice exhibited decreases in the release of IL-4, IL-5, IL-13, eotaxin-1, and tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF); inhibited T(H)2 functioning via a decrease in IL-4 production; and exhibited attenuation of OVA-induced lung eosinophilia, airway hyperresponsiveness, and airway remodeling. These results suggest that brazilin exhibits anti-T(H)2 effects both in vitro and in vivo and may possess therapeutic potential for allergic diseases.