Alaternin and emodin with hydroxyl radical inhibitory and/or scavenging activities and hepatoprotective activity on tacrine-induced cytotoxicity in HepG2 cells

A Review on Bioactive Anthraquinone and Derivatives as the Regulators for ROS

Anthraquinones are bioactive natural products, which are often found in medicinal herbs. These compounds exert antioxidant-related pharmacological actions including neuroprotective effects, anti-inflammation, anticancer, hepatoprotective effects and anti-aging, etc. Considering the benefits from their pharmacological use, recently, there was an upsurge in the development and utilization of anthraquinones as reactive oxygen species (ROS) regulators. In this review, a deep discussion was carried out on their antioxidant activities and the structure-activity relationships. The antioxidant mechanisms and the chemistry behind the antioxidant activities of both natural and synthesized compounds were furtherly explored and demonstrated. Due to the specific chemical activity of ROS, antioxidants are essential for human health. Therefore, the development of reagents that regulate the imbalance between ROS formation and elimination should be more extensive and rational, and the exploration of antioxidant mechanisms of anthraquinones may provide new therapeutic tools and ideas for various diseases mediated by ROS.

Waterless Dyeing and In Vitro Toxicological Properties of Biocolorants from Cortinarius sanguineus

As a part of an ongoing interest in identifying environmentally friendly alternatives to synthetic dyes and in using liquid CO2 as a waterless medium for applying the resulting colorants to textiles, our attention turned to yellow-to-red biocolorants produced by Cortinarius sanguineus fungus. The three principal target anthraquinone colorants (emodin, dermocybin, and dermorubin) were isolated from the fungal bodies using a liquid-liquid separation method and characterized using 700 MHz NMR and high-resolution mass spectral analyses. Following structure confirmations, the three colorants were examined for dyeing synthetic polyester (PET) textile fibers in supercritical CO2. We found that all three biocolorants were suitable for dyeing PET fibers using this technology, and our attention then turned to determining their toxicological properties. As emodin has shown mutagenic potential in previous studies, we concentrated our present toxicity studies on dermocybin and dermorubin. Both colorants were non-mutagenic, presented low cellular toxicity, and did not induce skin sensitization. Taken together, our results indicate that dermocybin and dermorubin possess the technical and toxicological properties needed for consideration as synthetic dye alternatives under conditions that are free of wastewater production.

A review of alpha-glucosidase inhibitors from plants as potential candidates for the treatment of type-2 diabetes

Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. Cardiovascular diseases, kidney damage and neuropathy are the main cause of high mortality rates among individuals with diabetes. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target alpha-amylase and alpha-glucosidase, enzymes that catalyzes starch hydrolysis in the intestine. At present, approved inhibitors for these enzymes are restricted to acarbose, miglitol and voglibose. Although these inhibitors retard glucose absorption, undesirable gastrointestinal side effects impede their application. Therefore, research efforts continue to seek novel inhibitors with improved efficacy and minimal side effects. Natural products of plant origin have been a valuable source of therapeutic agents with lesser toxicity and side effects. The anti-diabetic potential through alpha-glucosidase inhibition of plant-derived molecules are summarized in this review. Eight molecules (Taxumariene F, Akebonoic acid, Morusin, Rhaponticin, Procyanidin A2, Alaternin, Mulberrofuran K and Psoralidin) were selected as promising drug candidates and their pharmacokinetic properties and toxicity were discussed where available.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-021-09773-1.

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.

Perspective on the application of medicinal plants and natural products in wound healing: A mechanistic review

Wound is defined as any injury to the body such as damage to the epidermis of the skin and disturbance to its normal anatomy and function. Since ancient times, the importance of wound healing has been recognized, and many efforts have been made to develop novel wound dressings made of the best material for rapid and effective wound healing. Medicinal plants play a great role in the wound healing process. In recent decades, many studies have focused on the development of novel wound dressings that incorporate medicinal plant extracts or their purified active compounds, which are potential alternatives to conventional wound dressings. Several studies have also investigated the mechanism of action of various herbal medicines in wound healing process. This paper attempts to highlight and review the mechanistic perspective of wound healing mediated by plant-based natural products. The findings showed that herbal medicines act through multiple mechanisms and are involved in various stages of wound healing. Some herbal medicines increase the expression of vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) which play important role in stimulation of re-epithelialization, angiogenesis, formation of granulation tissue, and collagen fiber deposition. Some other wound dressing containing herbal medicines act as inhibitor of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS) protein expression thereby inducing antioxidant and anti-inflammatory properties in various phases of the wound healing process. Besides the growing public interest in traditional and alternative medicine, the use of herbal medicine and natural products for wound healing has many advantages over conventional medicines, including greater effectiveness due to diverse mechanisms of action, antibacterial activity, and safety in long-term wound dressing usage.

Emodin Derivatives as Multi-Target-Directed Ligands Inhibiting Monoamine Oxidase and Antagonizing Vasopressin V1A Receptors

The brain neurotransmitter level is associated with the pathology of various neurodegenerative diseases, and age-dependent increase in the blood level of vasopressin, human brain monoamine oxidase (hMAO) level, oxidative stress, and imbalance in aminergic signaling are common disease-modifying factors leading to various neurodegenerative disorders. Based on the reports of emodin in hMAO inhibition and antagonist effect on the vasopressin V_1A receptor, in this study we synthesized six emodin derivatives and evaluated their effects on MAO activity and G protein-coupled receptors. Among them, 4-hydroxyemodin and 5-hydroxyemodin were potent inhibitors of hMAO, and 2-hydroxyemodin and 5-hydroxyemodin were good V_1AR antagonists. In silico molecular docking simulation revealed that the hydroxyl group at C2, C4, and C5 of the respective compounds interacted with prime residues, which corroborates the in vitro effect. Likewise, these three derivatives were predicted to have good drug-like properties. Overall, our study demonstrates that the hydroxyl derivatives of emodin are multi-target-directed ligands that may act as leads for the design and development of a therapy for central nervous system disorders.

A natural flavonoid, apigenin isolated from Clerodendrum viscosum leaves, induces G2/M phase cell cycle arrest and apoptosis in MCF-7 cells through the regulation of p53 and caspase-cascade pathway

BACKGROUND

With 9.6 million deaths in 2018, cancer remains the second leading cause of death worldwide. Breast cancer is the most deadly type of cancer among females, with 55.2% of crude incidence rate and 16.6% of crude mortality rate.

PURPOSE

The present study was aimed to investigate the anti-breast cancer potential of natural dietary flavonoid, apigenin isolated from Clerodendrum viscosum leaves.

METHODS

Apigenin was evaluated for in-depth anticancer activity in MCF-7 cells using cell viability assay, cell cycle analysis, Annexin-V-FLUOS staining, ROS induction, morphological analysis, and western blot analysis.

RESULTS

Apigenin showed selective cytotoxicity on MCF-7 cells with an IC₅₀-56.72 ± 2.35 µM, while negligible cytotoxicity was observed on WI-38 cells. Further, the flow cytometer-based analysis showed that apigenin halted MCF-7 cells in the G2/M phase arrest followed by dose-dependent apoptosis. Moreover, the FACS and confocal microscopy results confirmed the elevation of intracellular ROS and nuclear fragmentation in apigenin-treated MCF-7 cells. Western blots showed up-regulation of cell cycle regulatory proteins, increased p53 expression, Bax/Bcl-2 ratio, activation of caspases, and cleavage of PARP. Finally, apigenin treatment in the presence of Pifithrin-µ showed decreased apoptotic population and it was further confirmed through western blotting study. The results revealed the vital role of p53 in apigenin-induced apoptosis in MCF-7 cells.

CONCLUSIONS

In the present findings, treatment of apigenin-induced intracellular ROS in MCF-7 cells followed by induction of G2/M phase cell cycle arrest and further apoptosis through the regulation of p53 and caspase-cascade signaling pathway.

Cassia tora Linn.: A boon to Alzheimer's disease for its anti-amyloidogenic and cholinergic activities

BACKGROUND

Drug discovery from natural products as alternatives for Alzheimer's disease (AD) is a current trend. For which plant is an alternative for searching potential molecule for treating AD. Availability of Cassia tora as weed and abundance in nature makes it as potential source. Many plants group under Leguminosae family has potential medicinal property of which Cassia tora is an appropriate choice, to know potency against AD. Etiology of AD is described by senile plaques and neurofibrillary tangles. The Aβ₄₂ has key major role in forming plaques by forming structures like protobirils, oligomers and final fibrilar like structures. Even at in vitro conditions, the peptides have a fibrilar like structure, which was exploited to preliminary screening of natural sources that may be effective in treating AD.

HYPOTHESIS/PURPOSE

The design of the study was to unravel the potential medicinal property of Cassia tora for its antioxidant, cholinergic and aggregation inhibition activity.

STUDY DESIGN

We evidenced that the methanol (MeOH), n-hexane (n-hex), petroleum ether (PE) and aqueous (aq) extracts from the leaves of Cassia tora (C. tora) were investigated for their inhibitory activity against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and anti-amyloidogenic assays. The antioxidant effect using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, total phenolic and flavonoid contents of the extracts were determined using Folin-Ciocaltaeu's and aluminum chloride (AlCl₃) reagents, respectively.

RESULTS

The methanol extract of C. tora exerted the highest inhibition against AChE (55.38 ± 2.28%) and BChE inhibition (50.02 ± 0.79%) at 100µg/ml concentration. The methanol extract was also found more active in the antioxidant test. The aggregation kinetics was monitored using thioflavin-T (ThT) assay and transmission electron microscopy (TEM) technique.

CONCLUSION

The results showed that C. tora methanol extract is able to inhibit the Aβ₄₂ aggregation from monomers and oligomers and also able to dis-aggregate the pre-formed fibrils. The study provides an insight on finding new natural products for AD therapeutics.

Cytotoxic effects of the anthraquinone derivatives 1'-deoxyrhodoptilometrin and (S)-(-)-rhodoptilometrin isolated from the marine echinoderm Comanthus sp

We investigated cytotoxic effects of the anthraquinone derivatives 1'-deoxyrhodoptilometrin (SE11) and (S)-(-)-rhodoptilometrin (SE16) isolated from the marine echinoderm Comanthus sp. in two tumor cell lines (C6 glioma, Hct116 colon carcinoma). Both compounds showed cytotoxic effects, with SE11 [IC₅₀-value (MTT assay): 13.1 µM in Hct116 cells] showing a higher potency to induce apoptotic and necrotic cell death. No generation of oxidative stress was detectable (DCF assay), and also no modulation of Nrf2/ARE and NFκB signaling could be shown. Investigation of 23 protein kinases associated with cell proliferation, survival, metastasis, and angiogenesis showed that both compounds were potent inhibitors of distinct kinases, e.g., IGF1-receptor kinase, focal adhesion kinase, and EGF receptor kinase with SE11 being a more potent compound (IC₅₀ values: 5, 18.4 and 4 µM, respectively). SE11 caused a decrease in ERK phosphorylation which may be a consequence of the inhibition of EGF receptor kinase by this compound. Since an inhibition of the EGF receptor/MAPK pathway is an important target for diverse cytostatic drugs, we suggest that the anthraquinone derivative 1'-deoxyrhodoptilometrin (SE11) may be an interesting lead structure for the development of new anticancer drugs.

Cassia tora Seed Extract and Its Active Compound Aurantio-obtusin Inhibit Allergic Responses in IgE-Mediated Mast Cells and Anaphylactic Models

Cassia tora seed is widely used due to its various biological properties including anticancer, antidiabetic, and anti-inflammatory effects. However, there has been no report of the effects of C. tora seed extract (CTE) on immunoglobulin E (IgE)-mediated allergic responses. In this research, we demonstrated the effects of CTE and its active compound aurantio-obtusin on IgE-sensitized allergic reactions in mast cells and passive cutaneous anaphylaxis (PCA). CTE and aurantio-obtusin suppressed degranulation, histamine production, and reactive oxygen species generation and inhibited the production and mRNA expression of tumor necrosis factor-α and interleukin-4. CTE and aurantio-obtusin also suppressed the prostaglandin E2 production and expression of cyclooxygenase 2. Furthermore, CTE and aurantio-obtusin suppressed IgE-mediated FcεRI signaling such as phosphorylation of Syk, protein kinase Cμ, phospholipase Cγ, and extracellular signal-regulated kinases. CTE and aurantio-obtusin blocked mast cell-dependent PCA in IgE-mediated mice. These results suggest that CTE and aurantio-obtusin are a beneficial treatment for allergy-related diseases.

Protective effect of fucosterol isolated from the edible brown algae, Ecklonia stolonifera and Eisenia bicyclis, on tert-butyl hydroperoxide- and tacrine-induced HepG2 cell injury

OBJECTIVES

Fucosterol is the primary sterol found in brown algae. Recently, considerable interest has been generated regarding fucosterol due to its potential antioxidant, anti-inflammatory and antidiabetic effects. The aim of this study was to investigate the protective effects of fucosterol on tert-butyl hydroperoxide (t-BHP)- and tacrine-induced oxidative stress in HepG2 cells.

METHODS

Fucosterol by itself exhibited no cytotoxicity at concentrations below 100 μm by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The increased intracellular reactive oxygen species (ROS) and decreased glutathione levels observed in t-BHP- and tacrine-treated HepG2 cells were ameliorated by fucosterol pretreatment, indicating that the protective effects of fucosterol are mediated by the induction of cellular defence mechanisms against oxidative stress. Moreover, elevated alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in tacrine-treated mice were significantly reduced after oral administration of fucosterol.

KEY FINDINGS

The hepatoprotective effects of fucosterol may occur via an increase in the hepatic level of glutathione and a decrease in ROS production, thereby preventing hepatic damage and the resultant increases in ALT and AST activity.

CONCLUSION

These results suggest that fucosterol may be an effective hepatoprotective agent that could be useful for preventive therapies against oxidative stress-related hepatotoxicity.

Methanolic Extract of Asterina pectinifera inhibits LPS-Induced Inflammatory Mediators in Murine Macrophage

This study aimed to elucidate anti-inflammatory activities from extracts of Asterina pectinifera on nitric oxide (NO) production, TNF-α and IL-6 release in lipopolysaccharide (LPS) -stimulated murine macrophage cell, RAW264.7. We prepared the methanolic extracts (60-MAP, 70-MAP, 80-MAP and 90-MAP) , aqueous extract (W-AP) and functional bioactive compound fraction (He-AP and EA-AP) from Asterina pectinifera according to extract method. The 60-MAP, 70-MAP, 80-MAP, 90-MAP and W-AP were significantly suppressed LPS-induced production NO, TNF-α and IL-6 secretion in a concentration-dependent manner (P < 0.05) . Especially, 80-MAP by extracted 80% methanol had the strongest activity in reduction of inflammatory mediators among these extracts. Indeed, to identify active fraction, which contained potential bioactive compounds, from 80-MAP of Asterina pectinifera, we tested anti-inflammatory activity of the He-AP or the EA-AP. The He-AP was next extracted from 80-MAP and the EA-AP were extracted from the other methanol layer except the He-AP. The EA-AP demonstrated a strong anti-inflammatory effect through its ability to reduce NO production and it also inhibited the production of proinflammatory cytokines such as IL-6 and TNF-α at low concentration. These results suggested that the methanolic extract from Asterina pectinifera had the potential inhibitory effects on the production of these inflammatory mediators.

Evaluation of the protective effect of Rhei Radix et Rhizoma against α-naphthylisothiocyanate induced liver injury based on metabolic profile of bile acids

ETHNOPHARMACOLOGICAL RELEVANCE

To evaluate the hepatoprotective effect of the root and rhizome of Rhubarb (Rhei Radix et Rhizoma) against α-naphthylisothiocyanate (ANIT)-induced liver injury using metabolic profile of bile acids (BAs) along with biochemical parameters and histological alterations.

MATERIALS AND METHODS

Ultra-performance liquid chromatography coupled with quadrupole mass spectrometry (UPLC-MS) was applied to determinate the concentration of BAs, which was followed by multivariate statistical analysis of Principal Component Analysis (PCA) and Partial Least Squares Discriminate Analysis (PLS-DA).

RESULTS

Based on PCA results, three groups (Vehicle group, ANIT group and RhO+ANIT group) were clearly distinguished. Tauro-cholic acid (TCA), tauro-hyodesoxycholic acid (THDCA), glyco-cholic acid (GCA), and glyco-chenodeoxycholic acid (GCDCA) were proved to be the most important markers corresponding to ANIT-induced liver injury and protection provided by Rhubarb, which is further confirmed by PLS-DA. A correlation was found between the foregoing BAs and biochemical parameters including serum aspartate aminotransferase (ALT) and aspartate aminotransferase (AST), which confirmed that TCA, THDAC, GCA, and GCDCA could be considered as sensitive biomarkers.

CONCLUSION

The variance of the BAs contents can be used to evaluate ANIT-induced hepatotoxicity caused by ANIT and protective effects of Rhubarb. It also lays the foundation for the further research on the mechanisms of cholestasis as well as the therapeutic effect of Rhubarb.

Emodin reverses gemcitabine resistance in pancreatic cancer cells via the mitochondrial apoptosis pathway in vitro

Gemcitabine resistance is a common problem of pancreatic cancer chemotherapy, and how to reverse it plays an important role in the treatment of pancreatic cancer. This study investigated the effect of emodin on the gemcitabine-resistant pancreatic cancer cell line SW1990/Gem, and explored the potential mechanism of its action. SW1990/Gem was obtained by culture of the pancreatic cancer cell line SW1990 in vitro by intermittently increasing the concentration of gemcitabine in the culture medium for 10 months, observing the morphology using inverted microscopy. SW1990/Gem cells were pretreated with emodin (10 μM) for different periods followed by treatment with gemcitabine (20 μM) for 48 h; cell proliferation was tested by MTT assay. SW1990/Gem cells were treated by emodin with different concentrations for 48 h, cell apoptosis was detected by flow cytometry (FCM). The expression of gene and protein, such as MDR-1 (P-gp), NF-κB, Bcl-2, Bax, cytochrome-C (cytosol), caspase-9 and -3 were measured by RT-PCR and Western blotting. The function of P-gp in SW1990/Gem cells was checked by FCM. The results showed that the SW1990/Gem cells changed greatly in morphology and the resistance index was 48.63. Emodin promoted cell apoptosis of the gemcitabine-resistant cell line SW1990/Gem in a dose-dependent manner. Emodin enhanced the SW1990/Gem cell sensitivity to gemcitabine in a time-dependent manner. Emodin monotherapy or combination with gemcitabine both decreased the gene and protein expression levels of MDR-1 (P-gp), NF-κB and Bcl-2 and inhibited the function of P-gp, but increased the expression levels of Bax, cytochrome-C (cytosol), caspase-9 and -3, and promoted cell apoptosis. This demonstrated that emodin had a reversing effect on the gemcitabine-resistant cell line SW1990/Gem, possibly via decreasing the function of P-gp and activating the mitochondrial apoptosis pathway in vitro.

Antitumor activities of an anthraquinone fraction isolated from in vitro cultures of Ophiorrhiza rugosa var decumbens

The biological effects of the anthraquinone fraction (AQf) isolated from in vitro cultures of Ophiorrhiza rugosa Wall. var decumbens (Rubiaceae) were evaluated. AQf showed differential activity on reactive oxygen species; it mediated the generation of superoxide radical and inhibited hydroxyl radical and lipid peroxidation. No considerable nitric oxide scavenging activity was observed for AQf. The AQf induced 50% cytotoxicity in Ehrlich ascites carcinoma and Dalton's lymphoma ascites at concentrations of 130 and 60 µg/mL, respectively. It effectively reduced the inflammation induced by carrageenan in mice. An AQf concentration of 200 mg/kg body weight reduced solid tumor progression in mice. It also prolonged the life span of ascites tumor-bearing mice compared with control mice.

Inhibitory activities of Cassia tora and its anthraquinone constituents on angiotensin-converting enzyme

As a component of our program that pertains to the isolation of antihypertensive agents derived from natural products, we screened the bioactivity of seeds from raw and roasted Cassia tora via angiotensin converting enzyme (ACE) inhibitory assays. We found that both of the MeOH extracts from the raw and roasted C. tora exhibited significant inhibitory properties against ACE, demonstrating more than 50% inhibition at a concentration of 163.93 microg/mL. Emodin (3), alaternin (4), gluco-obtusifolin (5), cassiaside (6), gluco-aurantioobtusin (7), cassitoroside (8), toralactone gentiobioside (9), and chrysophanol triglucoside (10) had been previously isolated; however, questin (1) and 2-hydroxyemodin 1-methylether (2) were isolated from C. tora for the first time in this study. Among them, only anthraquinone glycoside (7) demonstrated marked inhibitory activity against ACE, with an IC(50) value of 30.24 +/- 0.20 microM. Conversely, aurantioobtusin (7a), obtained from the acid hydrolysis of 7, showed no activity. Further inhibitory kinetics analyzed from Lineweaver-Burk plots showed 7 to be a competitive inhibitor with a Ki value of 8.3 x 10(-5) M. Moreover, compound 7 showed marked inhibitory and scavenging activities with an IC(50) value of 49.64 +/- 0.37 microM (positive control; trolox: 26.07 +/- 1.05 microM) for total reactive oxygen species generation, and 4.60 +/- 1.12 microM (positive control; penicillamine: 0.24 +/- 0.04 microM) for ONOO(-).

The seed extract of Cassia obtusifolia offers neuroprotection to mouse hippocampal cultures

The precise causative factors in neurodegenerative diseases such as Alzheimer's (AD) and Parkinson's disease remain elusive, but mechanisms implicated comprise excitotoxicity, mitochondrial dysfunction, and in the case of AD, the amyloid beta peptide (Abeta). Current therapeutic strategies for such disorders are very limited; thus, traditional herbal medicines currently receive increased attention. The seeds of Cassia obtisufolia have long been used in traditional eastern medicine and more recently the ethanolic fraction of the seeds (COE) has been shown to attenuate memory impairments in mice. In this study, we set out to determine the effect of COE (range: 0.1 - 10 microg/ml) on calcium dysregulation and cell death models in mouse primary hippocampal cultures implicated in general neurodegenerative processes and in the pathogenesis of AD: excitotoxicity, mitochondrial dysfunction, and Abeta toxicity. It was found that treatment with COE attenuated secondary Ca2+ dysregulation induced by NMDA (700 microM), while a pre-application of COE also reduced NMDA-induced cell death. Furthermore, COE was neuroprotective against the mitochondrial toxin 3-NP (1 mM), while having no significant effect on cell death induced by incubation with naturally-secreted oligomers of Abeta (8.2 pg/ml). Collectively, these results are important for the therapeutic use of COE in the treatment of neurodegenerative disorders.

Hepatoprotective effect of Cirsium arisanense Kitamura in tacrine-treated hepatoma Hep 3B cells and C57BL mice

Cirsium arisanense Kitamura (Compositae) has been used for hundreds of years in Taiwan as a folk medicine for hepatoprotection. However, no scientific research has demonstrated this effect. In the present study, we extracted the phenol-containing aqueous components of C. arisanense roots (CaR) and leaves/stem (CaL), and then assessed their hepatoprotective activities in both human hepatocellular carcinoma Hep 3B cells and C57BL/6 mice strain. High performance liquid chromatography (HPLC) analysis revealed that the components of CaR and CaL differed from those of the positive control silymarin. CaR exhibited a higher phenolic content and antioxidant capacity than CaL. Hep 3B cells treated with silymarin (0-200 microg/ml) demonstrated a concentration-dependent decrease in viability; however, both CaR and CaL did not exhibit any apparent cytotoxicity. Silymarin at 100 microg/ml, as well as CaR and CaL, not only protect Hep 3B cells from tacrine-induced hepatotoxicity but also decrease the expression of hepatitis B surface antigen (HBsAg). Moreover, an animal experiment demonstrated that CaR, CaL, and silymarin have hepatoprotective effects in C57BL/6 mice injected with tacrine, and they significantly decrease the levels of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST). These effects of CaR and silymarin, but not of CaL, may occur via an increase in the hepatic glutathione level and the elimination of the nitric oxide production. In conclusion, the phenol-containing aqueous components from C. arisanense have potential in hepatoprotection.

Emodin azide methyl anthraquinone derivative triggers mitochondrial-dependent cell apoptosis involving in caspase-8-mediated Bid cleavage

AMAD, an emodin azide methyl anthraquinone derivative, was extracted from the nature giant knotweed rhizome of traditional Chinese herbs. Here, we investigated the anticancer activities and signaling pathways implicated in AMAD-induced apoptosis in human breast cancer cell lines MDA-MB-453 and human lung adenocarcinoma Calu-3 cells. AMAD was found to have a potent cytotoxic effect on both cell lines. Hoechst 33258 staining and Annexin V/propidium iodide double staining exhibited the typical nuclear features of apoptosis and increased the proportion of apoptotic Annexin V-positive cells in a dose-dependent manner, respectively. Moreover, this apoptotic induction was associated with a collapse of the mitochondrial membrane potential and activated caspases (cysteine aspartase) cascade involving in caspase-8, caspase-9, caspase-3, and poly(ADP-ribose) polymerase cleavage in a concentration-dependent manner. It was noteworthy that AMAD also effectively cleaved Bid, a BH3 domain-containing proapoptotic Bcl-2 family member, and induced the subsequent release of cytochrome c from mitochondria into the cytosol. Furthermore, suppression of caspase-8 activity with Z-IETD-FMK partially inhibited release of cytochrome c and Bid cleavage induced by AMAD, whereas exposure to Z-LETD-FMK, a caspase-9 inhibitor, had no effect. Additionally, there was significant change in other mitochondrial membrane proteins triggered by AMAD, such as Bcl-xl and Bad. It was intriguing that AMAD decreased the generation of reactive oxygen species in both cell lines. DNA-binding assay exhibited apoptosis induced by AMAD was not involved in intercalating to DNA. Taken together, these data suggested that AMAD induced apoptosis via a mitochondrial pathway involving caspase-8/Bid activation in both cell lines.

Exploration of Emodin to treat alpha-naphthylisothiocyanate-induced cholestatic hepatitis via anti-inflammatory pathway

Emodin, 1,3,8-trihydroxy-6-methyl-anthraquinone, is an anthraquinone derivative from the roots of Rheum officinale Baill that has been used to treat many diseases in digestive system for thousands of years. This study is to disclose the mechanism of Emodin to treat cholestatic hepatitis via anti-inflammatory pathway. Rats were divided into Emodin, ursodeoxycholic acid, Dexamethasone, model and blank control groups with treatment of respective agent after administration of alpha-naphthylisothiocyanate. At 24 h, 48 h and 72 h time points after administration, liver function, pathological changes of hepatic tissue, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), cytokine-induced neutrophil chemoattractant (CINC)-1, macrophage inflammatory protein (MIP)-2, intercellular adhesion molecule (ICAM)-1, nuclear factor (NF)-kappaB and early growth response (Egr)-1, nitric oxide (NO) and inducible nitric oxide synthase (iNOS) were detected. As a result, compared to the controls, Emodin had a notable effect on rat's living condition, pathological manifestation of hepatic tissue, total bilirubin, direct bilirubin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P<0.05), but had little effect on alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT) and total bile acid. With Emodin intervention, levels of TNF-alpha, IL-6, MPO, MDA, CINC-1, MIP-2, ICAM-1 and translocation of NF-kappaB were remarkably decreased, and levels of NO and iNOS were markedly increased (P<0.05). Emodin had no effect on Egr-1. In conclusion, Emodin has a protective effect on hepatocytes and a restoring activity on cholestatic hepatitis by anti-inflammation. The effects are mainly due to antagonizing pro-inflammatory cytokines and mediators, inhibiting oxidative damage, improving hepatic microcirculation, reducing impairment signals, and controlling neutrophil infiltration.

Simultaneous determination of eight major bioactive compounds in Dachengqi Tang (DT) by high-performance liquid chromatography

Background

Dachengqi Tang (DT) is a common traditional Chinese medicine formula for expelling neire ('internal heat') in the stomach and intestines. There was no reliable analytical method available for the quality control of DT.

Methods

A high-performance liquid chromatography (HPLC) method with a reverse phase C₁₈ column (150 × 4.6 mm) was developed. The mobile phase was methanol with 0.2% acetic acid. Eight markers including naringin, hesperidin, aloe emodin, rhein, honokiol, magnolol, emodin and chrysophanol were determined.

Results

Regression analysis revealed a linear relationship between the concentrations of the markers and the peak area ratio of the standards and internal standard. The limit of detection (S/N = 3) and the limit of qualification (RSD < 20%) ranged from 0.21 to 0.43 ng/μl and 0.76 to 1.74 ng/μl respectively. The recovery was between 95.6% and 103.4%. The tests on the samples from three batches of DT showed that the profiles of the markers did not vary significantly among batches.

Conclusion

A reliable HPLC method for simultaneous determination of the eight markers in DT was developed.

Molecular mechanism of emodin action: transition from laxative ingredient to an antitumor agent

Anthraquinones represent a large family of compounds having diverse biological properties. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a naturally occurring anthraquinone present in the roots and barks of numerous plants, molds, and lichens, and an active ingredient of various Chinese herbs. Earlier studies have documented mutagenic/genotoxic effects of emodin, mainly in bacterial system. Emodin, first assigned to be a specific inhibitor of the protein tyrosine kinase p65lck, has now a number of cellular targets interacting with it. Its inhibitory effect on mammalian cell cycle modulation in specific oncogene overexpressed cells formed the basis of using this compound as an anticancer agent. Identification of apoptosis as a mechanism of elimination of cells treated with cytotoxic agents initiated new studies deciphering the mechanism of apoptosis induced by emodin. At present, its role in combination chemotherapy with standard drugs to reduce toxicity and to enhance efficacy is pursued vigorously. Its additional inhibitory effects on angiogenic and metastasis regulatory processes make emodin a sensible candidate as a specific blocker of tumor-associated events. Additionally, because of its quinone structure, emodin may interfere with electron transport process and in altering cellular redox status, which may account for its cytotoxic properties in different systems. However, there is no documentation available which reviews the biological activities of emodin, in particular, its growth inhibitory effects. This review is an attempt to analyze the biological properties of emodin, a molecule offering a broad therapeutic window, which in future may become a member of anticancer armamentarium.

High-performance liquid chromatographic method for simultaneous quantification of eight major biologically active ingredients in ‘Da-Chai-Hu-Tang’ Preparation

A simple, sensitive and specific high-performance liquid chromatographic method has been developed for the first time to simultaneously determine the eight major biologically active ingredients, namely paeoniflorin, naringin, sennoside A, baicalin, baicalein, saikosaponin a, rhein and emodin of the Chinese herbal formula Da-Chai-Hu-Tang. The contents of these marker substances in Da-Chai-Hu-Tang extract could be easily determined within 85 min. The assay was reproducible and accurate with overall intra-day variations and accuracy of less than 2% and more than 97.9%, respectively. Results indicate that the developed HPLC assay can be successfully utilized as a quality control method for simultaneous determination of eight representative substances in Da-Chai-Hu-Tang.

Hepatoprotective constituents of the edible brown alga Ecklonia stolonifera on tacrine-induced cytotoxicity in Hep G2 cells

In this study, ethanolic extracts from 18 seaweed variants were assessed for hepatoprotective activity against tacrine-induced cytotoxicity in Hep G2 cells. Only one of these, Ecklonia stolonifera Okamura (Laminariaceae), a member of the brown algae, exhibited promising hepatoprotective activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction obtained from the ethanolic extract of E. stolonifera, resulted in the isolation of several phlorotannins [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 2 and 4 were determined to protect Hep G2 cells against the cytotoxic effects of tacrine, with EC50 values of 62.0 and 79.2 microg/mL, respectively. Silybin, a well characterized hepatoprotective agent, was used as a positive control, and exhibited an EC50 value of 50.0 microg/mL. It has been suggested that the phlorotannins derived from marine brown algae might prove useful sources in the development of novel hepatoprotective agents.