Anti-inflammatory properties of anthraquinones and their relationship with the regulation of P-glycoprotein function and expression

Qualitative and quantitative analysis methods for quality control of rhubarb in Taiwan's markets

Introduction: Rhubarb is a traditional Chinese medicine (TCM) used to release heat and has cathartic effects. Official rhubarb in Taiwan Herbal Pharmacopeias 4th edition (THP 4th) and China Pharmacopeia 2020 (CP 2020) are the roots and rhizomes of Rheum palmatum L., Rheum tanguticum Maxim. ex Balf., and Rheum officinale Baill. However, the Rheum genus is a large genus with many different species, and owing to the similarity in appearance and taste with official rhubarb, there needs to be more clarity in the distinction between the species of rhubarb and their applications. Given the time-consuming and complicated extraction and chromatography methods outlined in pharmacopeias, we improved the qualitative analysis and quantitative analysis methods for rhubarb in the market. Hence, we applied our method to identify the species and quality of official and unofficial rhubarb. Method: We analyzed 21 rhubarb samples from the Taiwanese market using a proposed HPLC-based extraction and qualitative analysis employing eight markers: aloe-emodin, rhein, emodin, chrysophanol, physcion, rhapontigenin, rhaponticin, and resveratrol. Additionally, we developed a TLC method for the analysis of rhubarb. KEGG pathway analysis was used to clarify the phytochemical and pharmacological knowledge of official and unofficial rhubarb. Results: Rhein and rhapontigenin emerged as key markers to differentiate official and unofficial rhubarb. Rhapontigenin is abundant in unofficial rhubarb; however, rhein content was low. In contrast, their contents in official rhubarb were opposite to their contents in unofficial rhubarb. The TLC analysis used rhein and rhapontigenin to identify rhubarb in Taiwan's markets, whereas the KEGG pathway analysis revealed that anthraquinones and stilbenes affected different pathways. Discussion: Eight reference standards were used in this study to propose a quality control method for rhubarb in Taiwanese markets. We propose a rapid extraction method and quantitative analysis of rhubarb to differentiate between official and unofficial rhubarb.

Natural products for combating multidrug resistance in cancer

Cancer cells frequently develop resistance to chemotherapeutic therapies and targeted drugs, which has been a significant challenge in cancer management. With the growing advances in technologies in isolation and identification of natural products, the potential of natural products in combating cancer multidrug resistance has received substantial attention. Importantly, natural products can impact multiple targets, which can be valuable in overcoming drug resistance from different perspectives. In the current review, we will describe the well-established mechanisms underlying multidrug resistance, and introduce natural products that could target these multidrug resistant mechanisms. Specifically, we will discuss natural compounds such as curcumin, resveratrol, baicalein, chrysin and more, and their potential roles in combating multidrug resistance. This review article aims to provide a systematic summary of recent advances of natural products in combating cancer drug resistance, and will provide rationales for novel drug discovery.

Anthraquinones from Rhamnus alaternus L.: A Phytocosmetic Ingredient with Photoprotective and Antimelanogenesis Properties

The purpose of the present work was to develop a phytocosmetic sunscreen emulsion with antioxidant activity and an anti-melanogenic effect, containing an anthraquinone-enriched extract of Rhamnus alaternus (A.E.). Our findings demonstrated that A.E. decreased the levels of reactive oxygen species, DNA damage, and malondialdehyde induced by UVA in human keratinocytes and melanocytes. Furthermore, the calculated SPF value in vitro of the cream containing A.E. was 14.26±0.152. Later, it was shown that A.E. extract had an inhibitory effect on the amount of melanin. This extract could also reduce B16F10 intracellular tyrosinase activity. Besides, docking studies were carried out to provide a logical justification for the anti-tyrosinase potential. The findings showed that, A.E. may provide protection against UVA-induced oxidative stress and could be thought of as a viable treatment for hyperpigmentation disorders.

Oxidative Stress and Natural Products in Orthodontic Treatment: A Systematic Review

In recent years, orthodontics, a specialized branch of dentistry, has evolved considerably in terms of both techniques and materials used. Aimed at correcting dental malocclusions and craniofacial anomalies, it improves the functionality and aesthetics of the face and oral cavity. However, orthodontic treatment, in its developmental stages, may induce oxidative stress (O.S.) phenomena, with an increase in the production of reactive oxygen species (ROS), damaging the dental and periodontal tissues involved, affecting the short-, medium- and long-term results. Studies on the antioxidant effects of natural products (e.g., resveratrol, green tea, turmeric, etc.) in the medical field have aroused considerable interest in recent years. A systematic literature review was conducted on the PubMed, Scopus, and Web of Science databases using natural products (N.P.s), O.S., and orthodontic as keywords. The study aims to consider the determinants of the increase in ROS occurring during orthodontic treatment and the possibility of natural products being able to control and neutralize biochemical phenomena by restoring the physiological process in which the balance between the production of ROS and the ability of the body's antioxidant system to neutralize them is in favor of the latter.

Transcriptomic analyses provide new insights into green and purple color pigmentation in Rheum tanguticum medicinal plants

Background

Rheum tanguticum Maxim. ex Balf is a traditional Chinese medicinal plant that is commonly used to treat many ailments. It belongs to the Polygonacae family and grows in northwest and southwest China. At high elevations, the color of the plant's young leaves is purple, which gradually changes to green during the growth cycle. Anthraquinone, which is known for various biological activities, is the main bioactive compound in R. tanguticum. Although a significant amount of research has been done on R. tanguticum in the past, the lack of transcriptome data limits our knowledge of the gene regulatory networks involved in pigmentation and in the metabolism of bioactive compounds in Rheum species.

Methods

To fill this knowledge gap, we generated high-quality RNA-seq data and performed multi-tissue transcriptomic analyses of R. tanguticum.

Results

We found that three chlorophyll degradation enzymes (RtPPH, RtPao and RtRCCR) were highly expressed in purple samples, which suggests that the purple pigmentation is mainly due to the effects of chlorophyll degradation. Overall, these data may aid in drafting the transcriptional network in the regulation and biosynthesis of medicinally active compounds in the future.

Aloe-Emodin Suppresses Oxidative Stress and Inflammation via a PI3K-Dependent Mechanism in a Murine Model of Sepsis

Background

This study was designed to assess the impact of aloe-emodin (AE) on oxidative stress and inflammation in a murine model of LPS-induced sepsis. In addition, the mechanistic basis for anti-inflammatory and antioxidant activity was assessed.

Methods

Male ICR mice received an intraperitoneal injection of LPS (10 mg/kg), and the preventive properties of AE (80 or 150 mg/kg) on these mice were assessed by monitoring spleen index, and levels of inflammatory and oxidative stress-related factors. Peripheral blood TNF-α and IL-6 levels were assessed via ELISA kits, while changes in hepatic SOD and GSH-Px levels were assessed using appropriate biochemical kits. Splenic PI3K, AKT, and mTOR levels were assessed via qPCR and western blotting.

Results

Relative to animals in the LPS model group, those in the AE treatment groups exhibited reduced spleen index, decreased inflammatory cytokine levels, and improved SOD and GSH-Px activity in liver tissues. Splenic PI3K, Akt, and mTOR levels were also reduced in response to AE treatment.

Conclusions

These findings indicated that AE can alleviate sepsis-related tissue damage, inflammation, and oxidative stress, at least in part by suppressing the PI3K/Akt/mTOR signaling pathway. These results offer a clinical basis for the use of AE to treat sepsis and associated diseases.

Fuzzy identification of bioactive components for different efficacies of rhubarb by the back propagation neural network association analysis of UPLC-Q-TOF/MSE and integrated effects

Background

Rhei Radix et Rhizoma (rhubarb), as one of the typical representatives of multi-effect traditional Chinese medicines (TCMs), has been utilized in the treatment of various diseases due to its multicomponent nature. However, there are few systematic investigations for the corresponding effect of individual components in rhubarb. Hence, we aimed to develop a novel strategy to fuzzily identify bioactive components for different efficacies of rhubarb by the back propagation (BP) neural network association analysis of ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry for every data (UPLC-Q-TOF/MS^E) and integrated effects.

Methods

Through applying the fuzzy chemical identification, most components of rhubarb were classified into different chemical groups. Meanwhile the integration effect values of different efficacies can be determined by animal experiment evaluation and multi-attribute comprehensive indexes. Then the BP neural network was employed for association analysis of components and different efficacies by correlating the component contents determined from UPLC-Q-TOF/MS^E profiling and the integration effect values. Finally, the effect contribution of one type of components may be totaled to demonstrate the universal and individual characters for different efficacies of rhubarb.

Results

It suggested that combined anthraquinones, flavanols and their polymers may be the universal character to the multi-functional properties of rhubarb. Other components contributed to the individuality of rhubarb efficacies, including stilbene glycosides, anthranones and their dimers, free anthraquinones, chromones, gallic acid and gallotannins, butyrylbenzenes and their glycosides.

Conclusions

Our findings demonstrated that the bioactive components for different efficacies of rhubarb were not exactly the same and can be systematically differentiated by the network-oriented strategy. These efforts will advance our knowledge and understanding of the bioactive components in rhubarb and provide scientific evidence to support the expansion of its use in clinical applications and the further development of some products based on this medicinal herb.

Supplementary information

The online version contains supplementary material available at 10.1186/s13020-022-00612-9.

Recent development on COX-2 inhibitors as promising anti-inflammatory agents: The past 10 years

Cyclooxygenases play a vital role in inflammation and are responsible for the production of prostaglandins. Two cyclooxygenases are described, the constitutive cyclooxygenase-1 and the inducible cyclooxygenase-2, for which the target inhibitors are the non-steroidal anti-inflammatory drugs (NSAIDs). Prostaglandins are a class of lipid compounds that mediate acute and chronic inflammation. NSAIDs are the most frequent choices for treatment of inflammation. Nevertheless, currently used anti-inflammatory drugs have become associated with a variety of adverse effects which lead to diminished output even market withdrawal. Recently, more studies have been carried out on searching novel selective COX-2 inhibitors with safety profiles. In this review, we highlight the various structural classes of organic and natural scaffolds with efficient COX-2 inhibitory activity reported during 2011–2021. It will be valuable for pharmaceutical scientists to read up on the current chemicals to pave the way for subsequent research.

A systematic comparison of the effect of topically applied anthraquinone aglycones to relieve psoriasiform lesion: The evaluation of percutaneous absorption and anti-inflammatory potency

The anthraquinones derived from rhubarb are reported to have anti-inflammatory activity. The present study aimed to assess the topical application of rhubarb anthraquinone aglycones for psoriasis treatment. The antipsoriatic effect of five anthraquinones, including aloe-emodin, rhein, emodin, physcion, and chrysophanol, was compared to elucidate a structure-permeation relationship. Molecular modeling was employed to determine the physicochemical properties. Both macrophages (differentiated THP-1) and keratinocytes (HaCaT) were used to examine the anti-inflammatory activity in the cell-based study. The in vitro pig skin absorption showed that chrysophanol was the compound with the highest cutaneous accumulation. Topically applied rhein was detected to be largely delivered to the receptor compartment. The absorption of rhein was increased by 5-fold in the barrier-deficient skin as compared to intact skin. By stimulating macrophages with imiquimod (IMQ) to model the inflammation in psoriasis, it was found that the anthraquinones significantly reduced IL-6, IL-23, and TNF. The cytokine inhibition level was comparable for the five compounds. The anthraquinones suppressed cytokines by inhibiting the activation of MAPK and NF-κB signaling. The anthraquinones also downregulated IL-6, IL-8, and IL-24 in the inflammatory keratinocytes stimulated with TNF. Rhein and chrysophanol were comparable to curtail the STAT3 phosphorylation in keratinocytes induced by the conditioned medium of stimulated macrophages. The IMQ-induced psoriasiform mouse model demonstrated the improvement of scaling, erythema, and epidermal hyperplasia by topically applied rhein or chrysophanol. The epidermal acanthosis evoked by IMQ was reduced with rhein and chrysophanol by 3-fold. The histological profiles exhibit that both anthraquinone compounds diminished the number of macrophages and neutrophils in the lesional skin, skin-draining lymph node, and spleen. Rhein and chrysophanol showed multifunctional inhibition, by regulating several targets for alleviating psoriasiform inflammation.

Rubiadin exerts an acute and chronic anti-inflammatory effect in rodents

Rubiadin is identified as a bioactive anthraquinone that exists in some quinone rich plants. The current research was carried out to evaluate the potential anti-inflammatory impact of Rubiadin in acute and chronic inflammation test models in rodents. The anti-inflammatory activity of Rubiadin was examined in cotton pellet-induced granuloma and carrageenan-induced edema as chronic and acute inflammation models in rats. TNF-α level and histopathological changes were assessed using sampled foot tissue of rat in the acute model. Also, the IL-1β level was assessed in the chronic model. One-way ANOVA (post hoc Tukey's) analysis was used for comparing the groups. Rubiadin (0.5 mg/kg, i.p.) induced a significant reduction in TNF α level and the paw edema compared to the control group in carrageenan test. Also, it was observed that the anti-inflammatory activity of Rubiadin (0.5 mg/kg, i.p.) is comparable to mefenamic acid (30 mg/kg, i.p.) as the standard drug. Rubiadin was effective in granuloma induced by cotton pellet concerning the granuloma and transudate formation amount. Rubiadin's anti-inflammatory effects were associated with a significant IL-1β decrease in this model. The results suggest that Rubiadin as a natural compound can possess significant peripheral anti-inflammatory impacts.

From natural products to HDAC inhibitors: An overview of drug discovery and design strategy

Histone deacetylases (HDACs) play a key role in the homeostasis of protein acetylation in histones and have recently emerged as a therapeutic target for numerous diseases. The inhibition of HDACs may block angiogenesis, arrest cell growth, and lead to differentiation and apoptosis in tumour cells. Thus, HDAC inhibitors (HDACi) have received increasing attention and many of which are developed from natural sources. In the past few decades, naturally occurring HDACi have been identified to have potent anticancer activities, some of which have demonstrated promising therapeutic effects on haematological malignancies. In this review, we summarized the discovery and modification of HDAC inhibitors from natural sources, novel drug design that uses natural products as parent nuclei, and dual target design strategies that combine HDAC with non-HDAC targets.

Anethum sowa Roxb. ex fleming: A review on traditional uses, phytochemistry, pharmacological and toxicological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Anethum sowa Roxb. ex Fleming (Syn. Peucedanum sowa Roxb. ex Fleming, Family: Apiaceae) is a pharmacologically important as aromatic and medicinal plant. Various parts of this plant are used in traditional medicine systems for carminative, uterine and colic pain, digestion disorder, flatulence in babies, appetite-stimulating agent and used to treat mild flue and cough. The essential oil is used for aromatherapy. It is also used as a spice for food flavouring and culinary preparations in many Asian and European countries.

AIM OF THE REVIEW

This review aims to provide a comprehensive and critical assessment from the reported traditional and pharmaceutical uses and pharmacological activities of the extracts, essential oil and phytoconstituents with emphasis on its therapeutic potential as well as toxicological evaluation of A. sowa.

MATERIALS AND METHODS

Online search engines such as SciFinder®, GoogleScholar®, ResearchGate®, Web of Science®, Scopus®, PubMed and additional data from books, proceedings and local prints were searched using relevant keywords and terminologies related to A. sowa for critical analyses.

RESULTS

The literature studies demonstrated that A. sowa possesses several ethnopharmacological activities, including pharmaceutical prescriptions, traditional applications, and spice in food preparations. The phytochemical investigation conducted on crude extracts has been characterized and identified various classes of compounds, including coumarins, anthraquinone, terpenoids, alkaloid, benzodioxoles, phenolics, polyphenols, phenolic and polyphenols, fatty acids, phthalides and carotenoids. The extracts and compounds from the different parts of A. sowa showed diverse in vitro and in vivo biological activities including antioxidant, antiviral, antibacterial, analgesic and anti-inflammatory, Alzheimer associating neuromodulatory, cytotoxic, anticancer, antidiabetes, insecticidal and larvicidal.

CONCLUSION

A. sowa is a valuable medicinal plant which is especially used in food flavouring and culinary preparations. This review summarized the pertinent information on A. sowa and its traditional and culinary uses, as well as potential pharmacological properties of essential oils, extracts and isolated compounds. The traditional uses of A. sowa are supported by in vitro/vivo pharmacological studies; however, further investigation on A. sowa should be focused on isolation and identification of more active compounds and establish the links between the traditional uses and reported pharmacological activities with active compounds, as well as structure-activity relationship and in vivo mechanistic studies before integrated into the medicine. The toxicological report confirmed its safety. Nonetheless, pharmacokinetic evaluation tests to validate its bioavailability should be encouraged.

Cyclodextrin as Functional Carrier in Development of Mucoadhesive Tablets Containing Polygoni cuspidati Extract with Potential for Dental Applications

Polygoni cuspidati root is a resveratrol-rich source with anti-inflammatory, angiogenic and neuroprotective effects. The raw material was standardized for the content of resveratrol, for which there is a special justification for administration within the oral mucosa. To improve the solubility of resveratrol and to assure its high content in plant material, an ultrasound-assisted extraction method was applied. The addition of cyclodextrin was found to increase the extraction efficiency of resveratrol (from 13 to 297 µg per 1 g of plant material in case of 50% ethanol extracts) and enhanced its antioxidant activity as compared to pure Polygoni cuspidati extract/resveratrol. Cyclodextrin plays the role of a functional extract regarding technological properties (increasing the extraction of resveratrol from the extract, improving mucoadhesive properties). Therefore, the aim of this study was to develop mucoadhesive tablets containing combinations of the Polygoni cuspidati extract with a cyclodextrin carrier for buccal delivery. The tests sequentially included extract preparation and characterization of its physical and biological properties and then formulation studies with a broad description of the prototype properties. The test results indicate that cyclodextrin increases the efficiency of resveratrol extraction from Polygoni cuspidati rhizome, which is a rich source of resveratrol, and its extract enclosed in a mucoadhesive tablet guarantees prolonged action at the site of administration.

Folium Sennae Increased the Bioavailability of Methotrexate through Modulation on MRP 2 and BCRP

Folium Sennae (FS), a popular laxative (Senna), contains polyphenolic anthranoids, whose conjugation metabolites are probable modulators of multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). We suspected that the combined use of FS might alter the pharmacokinetics of various medicines transported by MRPs or BCRP. This study investigated the effect of FS on the pharmacokinetics of methotrexate (MTX), an anticancer drug and a probe substrate of MRPs/BCRP. Rats were orally administered MTX alone and with two dosage regimens of FS in a parallel design. The results show that 5.0 g/kg of FS significantly increased the AUC_0–2880, AUC_720–2880 and MRT of MTX by 45%, 102% and 42%, and the seventh dose of 2.5 g/kg of FS significantly enhanced the AUC_720–2880 and MRT by 78% and 42%, respectively. Mechanism studies indicated that the metabolites of FS (FSM) inhibited MRP 2 and BCRP. In conclusion, the combined use of FS increased the systemic exposure and MRT of MTX through inhibition on MRP 2 and BCRP.

Emodin - A natural anthraquinone derivative with diverse pharmacological activities

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural anthraquinone derivative that is present in numerous globally renowned herbal medicines. It is recognised as a protein tyrosine kinase inhibitor and as an anticancer drug, active against various tumour cells, including lung, breast, liver, and ovarian cancer cells. Recently, its role in combination chemotherapy with various allopathic medicines, to minimize their toxicity and to enhance their efficacy, has been studied. The use of emodin in these therapies is gaining popularity, due to fewer associated side effects compared with standard anticancer drugs. Emodin has a broad therapeutic window, and in addition to its antineoplastic activity, it displays anti-ulcer, anti-inflammatory, hepatoprotective, neuroprotective, antimicrobial, muscle relaxant, immunosuppressive and antifibrotic activities, in both in vitro and in vivo models. Although reviews on the anticancer activity of emodin have been published, none coherently unite all the pharmacological properties of emodin, particularly the anti-oxidant, antimicrobial, antidiabetic, immunosuppressive and hepatoprotective activities of the compound. Hence, in this review, all of the available data regarding the pharmacological properties of emodin are explored, with particular emphasis on the modes of action of the molecule. In addition, the manuscript details the occurrence, biosynthesis and chemical synthesis of the compound, as well as its toxic effects on biotic systems.

Explorations of ATP-Binding Cassette Transporters and Apoptosis Signal Pathways of 2-Hydroxyanthraquinone Substituted Cyclotriphosphazenes in MCF-7 and DLD-1 Cell Lines

BACKGROUND

As a class with biological properties, such as anti-cancer, anti-bacterial, anti-HIV, and various physical effects, phosphazene derivatives constitute the most striking part of inorganic compounds. Anthraquinones, on the other hand, are a broad family of compounds with a wide variety of biological properties; the biologically active anthraquinones have been used as valuable tool compounds for biochemical and pharmacological research.

OBJECTIVE

In this study, we aimed to investigate the effect of the anthraquinone substituted cyclotriphosphazene compounds on apoptosis and drug resistance in MCF-7 and DLD-1 cells.

METHODS

In breast and colon cells, mRNA levels of multi-drug resistance genes (ABCB1, ABCC3, ABCC10, ABCC11, and ABCG2), apoptotic genes (BAX, BCL-2, p53, and PARP), heat shock (HSP27, HSP40, HSP60, HSP90α) and endoplasmic reticulum chaperone genes (GRP78, and GRP94) were determined by the qPCR method. The amount of proteins of the cell cycle, HSPs, apoptosis, and related signaling pathways were measured by the membrane array kits.

RESULTS

Compounds 2, 3, 4, and 7 showed the most potent results on the ATP-binding cassette genes in both breast and colon cancer cells. These compounds have a remarkable effect on apoptotic, heat shock, and ER chaperone genes in cancer cells. Besides, these compounds induced protein levels of pro-apoptotic pathways, leading to apoptosis by inhibiting anti-apoptotic pathways. Also, these compounds decreased HSPs.

CONCLUSION

These compounds have potential properties that eliminate drug resistance, suppress heat shock and ER chaperone genes, and drag cells to apoptotic cell death and are notable for drug studies.

Rhubarb extract relieves constipation by stimulating mucus production in the colon and altering the intestinal flora

BACKGROUND

Constipation, mainly characterized by the difficulty in defecation, is a clinical symptom caused by a variety of factors. It can be manifested as normal or slow colonic transport abnormalities, which can occur alone or concurrently with defecation disorders. As there is not uniform definition and assessment standard, no clear plan could be used for the treatment of constipation. Although rhubarb, a traditional Chinese medicine, plays a therapeutic role in diseases involving constipation symptoms, the detailed mechanism of it in treating constipation remains unclear.

METHODS

A model of constipation-induced by diphenoxylate was prepared. Immunofluorescent staining was used to detect the expression of mucin 2 (MUC2), calnexin and chymase in colon. Western blotting was used to detect changes of tryptase and calnexin in the colon. And real-time polymerase chain reaction (PCR) was utilized to detect the changes of immunoglobulin-binding protein (Bip), X-box binding protein 1 (Xbp1) and C/EBP homologous protein (CHOP) of colonic goblet cells in mRNA levels. ELISA and biochemical kits were utilized to detect the changes of MUC2, Trefoil factor 3 (TFF3), acetylcholine, histamine and C-C motif chemokine ligand 5 (CCL5) in the colon. And the changes of colonic mucosa and intestinal flora of constipation model mice caused by rhubarb extract (RE) were analyzed to identify the mechanism of RE on the treatment of constipation.

RESULTS

RE promotes the secretion of colonic mucus by recruiting mast cells and enhancing the content of histamine and Ach in the mice colon. In the process, RE causes up-regulation of Bip and CHOP mRNA expression and down-regulation of Xbp1 and Xbp1s mRNA expression that induces ER stress of colonic epithelium associated with changes in the intestinal flora diversity and short-chain fatty acids content.

CONCLUSION

RE could relieve constipation by promoting the secretion of colonic mucus via mast cells activation and improving the intestinal microenvironment.

Acute regulation of apical ABC transporters in the gut. Potential influence on drug bioavailability

The extensive intestinal surface offers an advantage regarding nutrient, ion and water absorptive capacity but also brings along a high exposition to xenobiotics, including drugs of therapeutic use and food contaminants. After absorption of these compounds by the enterocytes, apical ABC transporters play a key role in secreting them back to the intestinal lumen, hence acting as a transcellular barrier. Rapid and reversible modulation of their activity is a subject of increasing interest for pharmacologists. On the one hand, a decrease in transporter activity may result in increased absorption of therapeutic agents given orally. On the other hand, an increase in transporter activity would decrease their absorption and therapeutic efficacy. Although of less relevance, apical ABC transporters also contribute to disposition of drugs systemically administered. This review article summarizes the present knowledge on the mechanisms aimed to rapidly regulate the activity of the main apical ABC transporters of the gut: multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP). Regulation of these mechanisms by drugs, drug delivery systems, drug excipients and nutritional components are particularly considered. This information could provide the basis for controlled regulation of bioavailability of therapeutic agents and at the same time would help to prevent potential drug-drug interactions.

Effects of emodin on ABC transporter gene expression in grass carp (Ctenopharyngodon idellus) exposed to diazinon

This study aimed to investigate the function of ATP-binding cassette (ABC) transporter genes in grass carp treated with emodin combined with diazinon (DZN) exposure. The transcription levels of five ABC transporter genes in different tissues of grass carp and at different time points were measured by real-time quantitative PCR (qRT-PCR). The analysis of different tissues showed higher ABCB1 expression in the skin (26-fold) and gill (2-fold) than in the liver. In addition, ABCB11 expression was higher in the skin (109-fold) and gill (57-fold) than in the liver, ABCC1 was more highly expressed in the gill (50-fold) than in the liver, and ABCG2 was expressed at higher levels in the skin (659-fold, p < 0.01), gill (628-fold, p < 0.01) and liver (659-fold, p < 0.01) than in brain tissue. The analysis of different time points revealed that the ABCB1, ABCB11, ABCC1, ABCC2 and ABCG2 genes were highly expressed at 24 h in the liver in the experimental group. However, analysis of the intestinal tissue of the experimental group showed that the expression of ABCB1 and ABCB11 peaked at 6 h, the expression of ABCC1 and ABCC2 peaked at 5 d, and the expression of ABCG2 peaked at 3 d. Furthermore, the emodin concentrations in the liver and intestine reached their peak levels (50.18 and 117.24 μg·ml⁻¹, respectively) after 48 and 1 h of treatment with emodin combined with DZN, respectively. The peak DZN concentrations in the liver (1.42 ng·ml⁻¹) and intestine (0.2 ng·ml⁻¹) were detected 3 and 6 h after emodin treatment combined with DZN, respectively. In conclusion, this study shows that the transcript levels of ABC transporters respond to the presence of emodin, which indicates their potential involvement in and contribution with the metabolic process in grass carp.

Chinese Herbal Medicine for Wilson's Disease: A Systematic Review and Meta-Analysis

Wilson's disease (WD) is a rare autosomal recessive inherited disorder of chronic copper toxicosis. Currently, Chinese herbal medicines (CHM) is widely used for WD. Here, we conducted an updated systematic review to investigate the efficacy and safety of CHM for WD and its possible mechanisms. Randomized-controlled clinical trials (RCTs), which compared CHM with Western conventional medicine or placebo for WD, were searched in six databases from inception to July 2017. The methodological quality was assessed using 7-item criteria from the Cochrane's collaboration tool. All the data were analyzed using Rev-Man 5.3 software. Eighteen studies involving 1,220 patients were identified for the final analyses. A score of study quality ranged from 2/7 to 4/7 points. Meta-analyses showed that CHM could significantly increase 24-h urinary copper excretion and improve liver function and the total clinical efficacy rate for WD compared with control (p < 0.05). Additionally, CHM was well tolerated in patients with WD. The underlying mechanisms of CHM for WD are associated with reversing the ATP7B mutants, exerting anti-oxidation, anti-inflammation, and anti-hepatic fibrosis effects. In conclusion, despite the apparent positive results, the present evidence supports, to a limited extent because of the methodological flaws and CHM heterogeneity, that CHM paratherapy can be used for patients with WD but could not be recommended as monotherapy in WD. Further rigorous RCTs focusing on individual CHM formula for WD are warranted.

Drug Bioavailability Enhancing Agents of Natural Origin (Bioenhancers) that Modulate Drug Membrane Permeation and Pre-Systemic Metabolism

Many new chemical entities are discovered with high therapeutic potential, however, many of these compounds exhibit unfavorable pharmacokinetic properties due to poor solubility and/or poor membrane permeation characteristics. The latter is mainly due to the lipid-like barrier imposed by epithelial mucosal layers, which have to be crossed by drug molecules in order to exert a therapeutic effect. Another barrier is the pre-systemic metabolic degradation of drug molecules, mainly by cytochrome P450 enzymes located in the intestinal enterocytes and liver hepatocytes. Although the nasal, buccal and pulmonary routes of administration avoid the first-pass effect, they are still dependent on absorption of drug molecules across the mucosal surfaces to achieve systemic drug delivery. Bioenhancers (drug absorption enhancers of natural origin) have been identified that can increase the quantity of unchanged drug that appears in the systemic blood circulation by means of modulating membrane permeation and/or pre-systemic metabolism. The aim of this paper is to provide an overview of natural bioenhancers and their main mechanisms of action for the nasal, buccal, pulmonary and oral routes of drug administration. Poorly bioavailable drugs such as large, hydrophilic therapeutics are often administered by injections. Bioenhancers may potentially be used to benefit patients by making systemic delivery of these poorly bioavailable drugs possible via alternative routes of administration (i.e., oral, nasal, buccal or pulmonary routes of administration) and may also reduce dosages of small molecular drugs and thereby reduce treatment costs.

The Importance of Anthraquinone and Its Analogues and Molecular Docking Calculation

In drug-delivery systems containing nano-drug structures, targeting the tumorous tissue by anthraquinone molecules with high biological activity, and reaching and destroying tumors by their tumor-killing effect reveals remarkable results for the treatment of tumors. The various biological activities of anthraquinones and their derivatives depend on molecular conformation; hence, their intra-cell interaction mechanisms including deoxyribonucleic acid (DNA), ribonucleic acid (RNA), enzymes, and hormones. Computer-based drug design plays an important role in the design of drugs and the determination of goals for them. Molecular docking has been widely used in structure-based drug design. The effects of anthraquinone analogues in tumor cells as a result of their interaction with DNA strand has increased the number of studies done on them, and they have been shown to have a wide range of applications in chemistry, medicine, pharmacy, materials, and especially in the field of biomolecules.

Raging the War Against Inflammation With Natural Products

Over the last few decade Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are the drugs of choice for treating numerous inflammatory diseases including rheumatoid arthritis. The NSAIDs produces anti-inflammatory activity via inhibiting cyclooxygenase enzyme, responsible for the conversation of arachidonic acid to prostaglandins. Likewise, cyclooxegenase-2 inhibitors (COX-2) selectively inhibit the COX-2 enzyme and produces significant anti-inflammatory, analgesic, and anti-pyretic activity without producing COX-1 associated gastrointestinal and renal side effects. In last two decades numerous selective COX-2 inhibitors (COXIBs) have been developed and approved for various inflammatory conditions. However, data from clinical trials have suggested that the prolong use of COX-2 inhibitors are also associated with life threatening cardiovascular side effects including ischemic heart failure and myocardial infection. In these scenario secondary metabolites from natural product offers a great hope for the development of novel anti-inflammatory compounds. Although majority of the natural product based compounds exhibit more selectively toward COX-1. However, the data suggest that slight structural modification can be helpful in developing COX-2 selective secondary metabolites with comparative efficacy and limited side effects. This review is an effort to highlight the secondary metabolites from terrestrial and marine source with significant COX-2 and COX-2 mediated PGE2 inhibitory activity, since it is anticipated that isolates with ability to inhibit COX-2 mediated PGE2 production would be useful in suppressing the inflammation and its classical sign and symptoms. Moreover, this review has highlighted the potential lead compounds including berberine, kaurenoic acid, α-cyperone, curcumin, and zedoarondiol for further development with the help of structure-activity relationship (SAR) studies and their current status.

Rheum australe, an endangered high-value medicinal herb of North Western Himalayas: a review of its botany, ethnomedical uses, phytochemistry and pharmacology

Rheum australe (Himalayan Rhubarb) is a multipurpose, endemic and endangered medicinal herb of North Western Himalayas. It finds extensive use as a medicinal herb since antiquity in different traditional systems of medicine to cure a wide range of ailments related to the circulatory, digestive, endocrine, respiratory and skeletal systems as well as to treat various infectious diseases. The remedying properties of this plant species are ascribed to a set of diverse bioactive secondary metabolite constituents, particularly anthraquinones (emodin, chrysophanol, physcion, aloe-emodin and rhein) and stilbenoids (piceatannol, resveratrol), besides dietary flavonoids known for their putative health benefits. Recent studies demonstrate the pharmacological efficacy of some of these metabolites and/or their derivatives as lead molecules for the treatment of various human diseases. Present review comprehensively covers the literature available on R. australe from 1980 to early 2018. The review provides up-to-date information available on its botany for easy identification of the plant, and origin and historical perspective detailing its trade and commerce. Distribution, therapeutic potential in relation to traditional uses and pharmacology, phytochemistry and general biosynthesis of major chemical constituents are also discussed. Additionally, efficient and reproducible in vitro propagation studies holding vital significance in preserving the natural germplasm of the plant and for its industrial exploitation have also been highlighted. The review presents a detailed perspective for future studies to conserve and sustainably make use of this endangered plant species at a commercial scale.

Methanol extract of Guettarda speciosa Linn. inhibits the production of inflammatory mediators through the inactivation of Syk and JNK in macrophages

Guettarda speciosa Linn. (G. speciosa, Rubiaceae) has been used as a traditional medicinal plant in Asia for the treatment of various inflammatory conditions, including cough, fever and maternal postpartum infection. However, the mechanisms underlying the anti‑inflammatory action of G. speciosa extracts have remained elusive. In the present study, the anti‑inflammatory effects of the methanol extract of G. speciosa (MGS) were investigated in murine macrophages by measuring the production of inflammatory mediators and the underlying mechanisms of action by performing immunoblotting analysis of proteins that are potentially involved. MGS reduced nitric oxide (NO) production through regulation of the expression of inducible NO synthase (iNOS) in lipopolysaccharide‑activated RAW 264.7 cells; however, cyclooxygenase‑2, the enzyme responsible for prostaglandin E2 production, was not affected at the mRNA or protein level. MGS reduced interleukin‑6 (IL‑6) production, but had no effect on tumor necrosis factor (TNF)‑α production. In addition, MGS suppressed the transcription of IL‑6, but not that of IL‑1β and TNF‑α. The effect of MGS on proinflammatory mediators resulted from the inhibition of the activation of spleen tyrosine kinase and c‑Jun N‑terminal kinase. In conclusion, the present study suggested that MGS may be a potential candidate for development as a therapeutic for alleviating inflammation.

Selection of chemical markers for the quality control of medicinal plants of the genus Cecropia

CONTEXT

Several Cecropia (Cecropiaceae) species are traditionally used in Latin America for the treatment of a variety of diseases including diabetes, arterial hypertension, asthma, bronchitis, anxiety, and inflammation. At present, a number of commercial products based on these plants have been introduced into the market with very little information on methods for guaranteeing their quality and safety.

OBJECTIVE

This work proposes potential chemical markers for the quality control of the raw materials of Cecropia obtusifolia Bertol., Cecropia peltata L., Cecropia glaziovii Snethl., Cecropia pachystachya Trécul, and Cecropia hololeuca Miq.

METHODS

The Herbal Chemical Marker Ranking System (Herb MaRS) developed by the National Institute of Complementary Medicine (NICM) at the University of Western Sydney was used for selecting chemical markers for the quality control of selected medicinal species of Cecropia. This review covers the period from 1982 to 2016.

RESULTS

Chlorogenic acid, flavonoidal glycosides (orientin, isoorientin, vitexin, isovitexin, and rutin), catechin, epicatechin, procyanidins (B2, B5, and C1), steroids (β-sitosterol), and triterpenoids (α-amyrin, pomolic, tormentic and ursolic acids) were selected as chemical markers for the quality control of the leaves.

CONCLUSION

It is necessary to establish comprehensive standards for guaranteeing quality, safety and efficacy of herbal drugs. The selection of adequate chemical markers for quality control purposes requires a good knowledge about the chemical composition of medicinal plants and their associated biological properties. To the best of our knowledge this review article is the first to address the identification and quantitative determination of the chemical markers for the genus Cecropia.

Emodin reverses leukemia multidrug resistance by competitive inhibition and downregulation of P-glycoprotein

Development of multidrug resistance (MDR) is a continuous clinical challenge partially due to the overexpression of P-glycoprotein (P-gp) for chronic myelogenous leukemia (CML) patients. Herein, we evaluated the inhibitory potency of emodin, a natural anthraquinone derivative isolated from Rheum palmatum L, on P-gp in P-gp positive K562/ADM cells. Competition experiments combined with molecular docking analysis were utilized to investigate the binding modes between emodin and binding sites of P-gp. Emodin reversed adriamycin resistance in K562/ADM cells accompanied with the decrease of P-gp protein expression, further increasing the uptake of rhodamine123 in both K562/ADM and Caco-2 cells, indicating the inhibition of P-gp efflux function. Moreover, when incubated with emodin under different conditions where P-gp was inhibited, K562/ADM cells displayed increasing intracellular uptake of emodin, suggesting that emodin may be the potential substrate of P-gp. Importantly, rhodamine 123 could increase the K_intrinsic (K_i) value of emodin linearly, whereas, verapamil could not, implying that emodin competitively bound to the R site of P-gp and noncompetition existed between emodin and verapamil at the M site, in a good accordance with the results of molecular docking that emodin bound to the R site of P-gp with higher affinity. Based on our results, we suggest that emodin might be used to modulate P-gp function and expression.

Experimental and theoretical studies of emodin interacting with a lipid bilayer of DMPC

Emodin is one of the most abundant anthraquinone derivatives found in nature. It is the active principle of some traditional herbal medicines with known biological activities. In this work, we combined experimental and theoretical studies to reveal information about location, orientation, interaction and perturbing effects of Emodin on lipid bilayers, where we have taken into account the neutral form of the Emodin (EMH) and its anionic/deprotonated form (EM^-). Using both UV/Visible spectrophotometric techniques and molecular dynamics (MD) simulations, we showed that both EMH and EM^- are located in a lipid membrane. Additionally, using MD simulations, we revealed that both forms of Emodin are very close to glycerol groups of the lipid molecules, with the EMH inserted more deeply into the bilayer and more disoriented relative to the normal of the membrane when compared with the EM^-, which is more exposed to interfacial water. Analysis of several structural properties of acyl chains of the lipids in a hydrated pure DMPC bilayer and in the presence of Emodin revealed that both EMH and EM^- affect the lipid bilayer, resulting in a remarkable disorder of the bilayer in the vicinity of the Emodin. However, the disorder caused by EMH is weaker than that caused by EM^-. Our results suggest that these disorders caused by Emodin might lead to distinct effects on lipid bilayers including its disruption which are reported in the literature.

Visualizing spatial distribution of small molecules in the rhubarb stalk (Rheum rhabarbarum) by surface-transfer mass spectrometry imaging

Laser desorption/ionization mass spectrometry imaging (LDI-MSI) with gold nanoparticle-enhanced target (AuNPET) was used for visualization of small molecules in the rhubarb stalk (Rheum rhabarbarum L.). Analysis was focused on spatial distribution of biologically active compounds which are found in rhubarb species. Detected compounds belong to a very wide range of chemical compound classes such as anthraquinone derivatives and their glucosides, stilbenes, anthocyanins, flavonoids, polyphenols, organic acids, chromenes, chromanones, chromone glycosides and vitamins. The analysis of the spatial distribution of these compounds in rhubarb stalk with the nanoparticle-rich surface of AuNPET target plate has been made without additional matrix and with minimal sample preparation steps.

Rhein attenuates inflammation through inhibition of NF-κB and NALP3 inflammasome in vivo and in vitro

Rhein is an important component in traditional Chinese herbal medicine formulations for gastrointestinal disorders, including inflammatory bowel diseases such as ulcerative colitis. In this study, we investigated the beneficial effects of rhein in inflammation models in the transgenic zebrafish line TG (corolla eGFP), in which both macrophages and neutrophils express eGFP and RAW264.7 macrophages. We found that the tail-cutting-induced migration of immune cells was significantly reduced in transgenic zebrafish treated with rhein. In addition, the production of proinflammatory cytokines, including IL-6, IL-1β, and tumor necrosis factor-α, were significantly reduced in lipopolysaccharide (LPS)-induced RAW264.7 macrophages treated with rhein. Parallel to the inhibition of proinflammatory cytokines, rhein significantly reduced phosphorylation levels of NF-κB p65 and inducible nitric oxide synthase, as well as COX-2 protein expression levels. Furthermore, rhein significantly reduced NALP3 and cleaved IL-1β expression in LPS + ATP-induced RAW264.7 macrophages. Thus, the present study demonstrates that rhein may exhibit its anti-inflammatory action via inhibition of NF-κB and NALP3 inflammasome pathways.

Effect of Trichilia monadelpha (Meliaceae) extracts on bone histomorphology in complete Freund's adjuvant-induced arthritis

AIM

This study aimed to assess the effect of petroleum ether extract (PEE), ethyl acetate extract (EthE), and ethanol extract (EAE) of Trichilia monadelpha stem bark on bone histomorphology in arthritis.

METHODS

Percentage inhibition of edema and arthritic scores in complete Freund's adjuvant-induced (0.1 ml of 5 mg/ml¹ of heat-killed Mycobacterium tuberculosis in paraffin oil-injected subplantar into the right hind paw) arthritic Sprague-Dawley rats treated with PEE, EthE, or EAE (10,30, and 100 mg/kg¹, respectively), dexamethasone (0.3-3.0 mg/kg¹), or methotrexate (0.1-1.0 mg/kg¹) over a 28-day period were estimated. Rat paws were radiographed and scored. Body weights were taken and paw tissues were harvested for histopathological studies.

RESULTS

The extracts significantly (P ≤ 0.01-0.0001) and dose dependently reduced the polyarthritic phase of arthritis. EAE and PEE significantly (P ≤ 0.01-0.0001) minimized edema spread from acute arthritic phase (days 0-10) to polyarthritic phase (days 10-28). EthE improved which deteriorated body weight in arthritis. All extracts significantly (P ≤ 0.05-0.01) improved arthritic score; reducing erythema, swelling and joint rigidity, and also significantly (P ≤ 0.05-0.01) reduced hyperplasia, pannus formation, and exudation of inflammatory cells into synovial spaces.

CONCLUSION

The stem bark extracts of T. monadelpha reduce bone tissue damage and resorption associated with adjuvant-induced arthritis, hence could be useful in managing arthritis in humans.

INHIBITORY EFFECT OF EMODIN ON RAW 264.7 ACTIVATED WITH DOUBLE STRANDED RNA ANALOGUE POLY I:C

Background:

Emodin (3-methyl-1, 6, 8-trihydroxyanthraquinone) is a compound which can be found in Polygoni Multiflori Radix (PMR). PMR is the root of Polygonum multiflorum. PMR is used to treat dizziness, spermatorrhea, sores, and scrofula as well as chronic malaria traditionally in China and Korea. The anti-tumor property of emodin was already reported. However, anti-viral activity of emodin on macrophages are not fully reported.

Materials and Methods:

Effects of emodin on RAW 264.7 mouse macrophages induced by polyinosinic-polycytidylic acid (poly I:C), a synthetic analog of double-stranded RNA, were evaluated.

Results:

Emodin restored the cell viability in poly I: C-induced RAW 264.7 at concentrations of up to 50 μM. Emodin significantly inhibited the production of nitric oxide, IL-1α, IL-Ιβ, IL-6, GM-CSF, G-CSF, M-CSF, MCP-1, MIP-1a, MIP-Ιβ, MIP-2, RANTES, and IP-10 as well as calcium release and mRNA expression of signal transducer and activated transcription 1 (STAT1) in poly I:C-induced RAW 264.7 (P < 0.05).

Conclusion:

This study shows the inhibitory effect of emodin on poly I: C-induced RAW 264.7 via calcium-STAT pathway.

Protective effect and potential mechanisms of Wei-Chang-An pill on high-dose 5-fluorouracil-induced intestinal mucositis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Wei-Chang-An pill (WCA pill), a traditional Chinese pharmaceutical preparation, possessed potential anti-inflammatory advantages and noteworthy gastrointestinal regulations in digestive diseases, which might represent a promising candidate for the treatment of intestinal mucositis (IM) induced by 5-fluorouracil (5-FU).

AIM OF THE STUDY

To analyze the bioactive constituents and investigate the effect of methanol extraction from WCA pill (WCA ext) on 5-FU induced IM with underlying mechanisms.

MATERIALS AND METHODS

The analysis of serum bioactive constituents after WCA ext administration in rats was carried out by UHPLC-Quadrupole-Time of Flight-Mass Spectrometry. In mice, IM was induced by 5-FU and physical manifestations were measured during the period of drug delivery. Half of mice were assessed with histology, expression of inflammatory cytokines in ileum and plasma via hematoxylin and eosin staining, immunohistochemical staining as well as cytokine enzyme-linked immunosorbent assay test, respectively. Besides, gastric emptying (GE) and gastrointestinal transit (GIT) were further tested in the other half of 5-FU induced mice.

RESULTS

Twenty-two compounds were identified or tentatively characterized. IM induced by 5-FU was improved significantly after treatment with WCA ext through reducing the body weight loss, relieving the severe diarrhea, and inhibiting the GE as well as GIT. Further assessments validated that WCA ext promoted the recovery of intestinal mucosa, evaluated the activity of enterocyte proliferation, maintained the integrity of tight junction, and ameliorated the inflammatory disturbances.

CONCLUSIONS

These results suggested that WCA ext promoted the restoration of intestinal function in 5-FU-induced IM via regulating multiple sites of actions in intestinal homeostasis. Accordingly, WCA pill might be a promising therapeutic candidate for the prevention of IM during cancer chemotherapy.

Analysis of the pharmacokinetics and metabolism of aloe-emodin following intravenous and oral administrations in rats

Aloe-emodin, a natural polyphenolic anthraquinone, has shown various beneficial bioactivities in vitro. The aim of this study was to investigate the pharmacokinetics and metabolism of aloe-emodin. Aloe-emodin was intravenously and orally administered to rats. The concentrations of aloe-emodin and rhein, a metabolite of aloe-emodin, were determined by HPLC method prior to and after hydrolysis with β-glucuronidase and sulfatase/β-glucuronidase. The results showed that the systemic exposures of aloe-emodin and its metabolites were ranked as aloe-emodin glucuronides (G) > rhein sulfates (S) > aloe-emodin > rhein and rhein G when aloe-emodin was given intravenously. In contrast, when aloe-emodin was administered orally, the parent form of aloe-emodin was not absorbed per se, and the systemic exposures of its metabolites were ranked as aloe-emodin G > rhein G > rhein. In conclusion, the metabolites of aloe-emodin are more important than the parent form for the bioactivities in vivo. Copyright © 2016 John Wiley & Sons, Ltd.

P-glycoprotein Mediated Efflux Modulators of Plant Origin: A Short Review

Drug efflux transporters such as P-glycoprotein (P-gp) help maintain cellular homeostasis but are also major contributors to the development of multidrug resistance (MDR) phenomena. Since P-gp was associated with MDR, several compounds showing potential to inhibit this transporter have been identified. Particular attention has been given to natural products, namely those of plant origin, looking for highly effective and safe P-gp inhibitors with little to no interaction with other cellular or metabolic processes. Here we abridge several examples of plant compounds from distinct classes, polyketides, lignans, anthraquinones, coumarins, alkaloids, mono- and sesqui-terpenes, steroids and limonoids, which have shown the ability to modulate in vitro or in vivo the P-gp activity.

Inhibition of human anthracycline reductases by emodin - A possible remedy for anthracycline resistance

The clinical application of anthracyclines, like daunorubicin and doxorubicin, is limited by two factors: dose-related cardiotoxicity and drug resistance. Both have been linked to reductive metabolism of the parent drug to their metabolites daunorubicinol and doxorubicinol, respectively. These metabolites show significantly less anti-neoplastic properties as their parent drugs and accumulate in cardiac tissue leading to chronic cardiotoxicity. Therefore, we aimed to identify novel and potent natural inhibitors for anthracycline reductases, which enhance the anticancer effect of anthracyclines by preventing the development of anthracycline resistance. Human enzymes responsible for the reductive metabolism of daunorubicin were tested for their sensitivity towards anthrachinones, in particular emodin and anthraflavic acid. Intense inhibition kinetic data for the most effective daunorubicin reductases, including IC50- and Ki-values, the mode of inhibition, as well as molecular docking, were compiled. Subsequently, a cytotoxicity profile and the ability of emodin to reverse daunorubicin resistance were determined using multiresistant A549 lung cancer and HepG2 liver cancer cells. Emodin potently inhibited the four main human daunorubicin reductases in vitro. Further, we could demonstrate that emodin is able to synergistically sensitize human cancer cells towards daunorubicin at clinically relevant concentrations. Therefore, emodin may yield the potential to enhance the therapeutic effectiveness of anthracyclines by preventing anthracycline resistance via inhibition of the anthracycline reductases. In symphony with its known pharmacological properties, emodin might be a compound of particular interest in the management of anthracycline chemotherapy efficacy and their adverse effects.

A Systematic Review of Rhubarb (a Traditional Chinese Medicine) Used for the Treatment of Experimental Sepsis

Sepsis is a global major health problem in great need for more effective therapy. For thousands of years, Rhubarb had been used for various diseases including severe infection. Pharmacological studies and trials reported that Rhubarb may be effective in treating sepsis, but the efficacy and the quality of evidence remain unclear since there is no systematic review on Rhubarb for sepsis. The present study is the first systematic review of Rhubarb used for the treatment of experimental sepsis in both English and Chinese literatures by identifying 27 studies from 7 databases. It showed that Rhubarb might be effective in reducing injuries in gastrointestinal tract, lung, and liver induced by sepsis, and its potential mechanisms might include reducing oxidative stress and inflammation, ameliorating microcirculatory disturbance, and maintaining immune balance. Yet the positive findings should be interpreted with caution due to poor methodological quality. In a word, Rhubarb might be a promising candidate that is worth further clinical and experimental trials for sepsis therapy.

Pharmacological mechanism underlying anti-inflammatory properties of two structurally divergent coumarins through the inhibition of pro-inflammatory enzymes and cytokines

Background

The aim of the present study is to investigate the effects of two structurally divergent coumarins, calipteryxin (1) and (3’S,4’S)-3’,4’-disenecioyloxy-3’,4’-dihydroseselin (2) from Seseli recinosum, in lipopolysaccharide (LPS)-stimulated murine macrophages.

Methods

The nitrite production was evaluated using Griess reagent. The protein and mRNA expression levels were investigated through Western blot and quantitative real time-PCR analyses. The NF-κB and AP-1 DNA-binding activities were assessed using an electrophoretic mobility shift assay. The docking studies were performed with Glide XP in Schrödinger suite (version 2013).

Results

The results of the present study revealed that calipteryxin (1) and (3’S,4’S)-3’,4’-disenecioyloxy-3’,4’-dihydroseselin (2) treatment showed potent inhibitory effects on pro-inflammatory enzymes and cytokines associated with molecular signaling pathways. Treatment with calipteryxin and (3’S,4’S)-3’,4’-disenecioyloxy-3’,4’-dihydroseselin also decreased the production of nitric oxide (NO), tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) in a dose-dependent manner. Additionally, both coumarins inhibited the LPS-induced protein and mRNA expression levels of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in RAW264.7 cells. To explore the potential mechanisms underlying the inhibitory activity of coumarin derivatives, the protein signaling pathways for NF-κB, mitogen-activated protein kinase (MAPK) and Akt were examined. Calipteryxin and (3’S,4’S)-3’,4’-disenecioyloxy-3’,4’-dihydroseselin markedly reduced the LPS-stimulated phosphorylation of IKKα/β, p-IκBα and IκBα degradation as well as the nuclear translocation of the p65 subunit of pro-inflammatory transcription factor NF-κB. In addition, calipteryxin and (3’S,4’S)-3’,4’-disenecioyloxy-3’,4’-dihydroseselin) considerably inhibited the LPS-induced expression of ERK, c-Jun N-terminal kinase (JNK), p38 and Akt proteins. Furthermore, both coumarins significantly inhibited c-Jun expression in the nucleus.

Conclusions

Taken together, these results support the therapeutic potential and molecular mechanism of calipteryxin and (3’S,4’S)-3’,4’-disenecioyloxy-3’,4’-dihydroseselin associated with inflammatory diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12950-015-0087-y) contains supplementary material, which is available to authorized users.

BME, a novel compound of anthraquinone, down regulated P-glycoprotein expression in doxorubicin-resistant human myelogenous leukemia (K562/DOX) cells via generation of reactive oxygen species

P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in tumor cells is still a main obstacle for the chemotherapeutic treatment of cancers. Thus, development of effective MDR reversing agents is an important approach in the clinic. The present study revealed that BME, a novel compound of anthraquinone, elevated intracellular accumulation of the P-gp substrates and reduced concentration resulting in 50% inhibition of cell growth (IC50) values for doxorubicin (DOX) in doxorubicin-resistant human myelogenous leukemia (K562/DOX) cells. Further more, BME was also reported to down regulated P-gp expression accompanying with generation of nontoxic low level of intracellular reactive oxygen species (iROS) and activation of extracellular signal-regulated kinase (ERK)1/2 as well as c-JUN N-terminal kinase (JNK). However, treatment with N-acetyl-cysteine (NAC), U0216 and SP600125 almost abolished actions of the BME mentioned above. These results indicated that the effect of the BME on the P-gp may be involved in generation of nontoxic low level of iROS and activation of ERK1/2 or JNK, which suggested valuable clues to screen and develop P-gp reversing agents.

Review of clinical studies of Polygonum multiflorum Thunb. and its isolated bioactive compounds

Polygonum multiflorum Thunb. (PMT), officially listed in the Chinese Pharmacopoeia, is one of the most popular perennial Chinese traditional medicines known as He shou wu in China and East Asia, and as Fo-ti in North America. Mounting pharmacological studies have stressed out its key benefice for the treatment of various diseases and medical conditions such as liver injury, cancer, diabetes, alopecia, atherosclerosis, and neurodegenerative diseases as well. International databases such as PubMed/Medline, Science citation Index and Google Scholar were searched for clinical studies recently published on P. multiflorum. Various clinical studies published articles were retrieved, providing information relevant to pharmacokinetics-pharmacodynamics analysis, sleep disorders, dyslipidemia treatment, and neurodegenerative diseases. This review is an effort to update the clinical picture of investigations ever carried on PMT and/or its isolated bio-compounds and to enlighten its therapeutic assessment.