Okicamelliaside targets the N-terminal chaperone pocket of HSP90 disrupts the chaperone protein interaction of HSP90-CDC37 and exerts antitumor activity.

Heat shock protein 90 (HSP90) has been recognized as a crucial target in cancer cells. However, various toxic reactions targeting the ATP binding site of HSP90 may not be the best choice for HSP90 inhibitors. In this paper, an ellagic acid derivative, namely, okicamelliaside (OCS), with antitumor effects was found. To identify potential anti-cancer mechanisms, an OCS photosensitive probe was applied to target fishing and tracing. Chemical proteomics and protein-drug interaction experiments have shown that HSP90 is a key target for OCS, with a strong binding affinity (KD = 6.45 µM). Mutation analysis of the target protein and molecular dynamics simulation revealed that OCS could competitively act on the key Glu-47 site at the N-terminal chaperone pocket of HSP90, where the co-chaperone CDC37 binds to HSP90, affect its stability and reduce the ∆Gbind of HSP90-CDC37. It was demonstrated that OCS destroys the protein-protein interactions of HSP90-CDC37; selectively affects downstream kinase client proteins of HSP90, including CDK4, P-AKT473, and P-ERK1/2; and exerts antitumor effects on A549 cells. Furthermore, tumor xenograft experiments demonstrated high antitumor activity and low toxicity of OCS in the same way. Our findings identified a novel N-terminal chaperone pocket natural inhibitor of HSP90, that is, OCS, which selectively inhibits the formation of the HSP90-CDC37 protein complex, and provided further insight into HSP90 inhibitors for anti-cancer candidate drugs.

DMAG, a novel countermeasure for the treatment of thrombocytopenia.

BACKGROUND: Thrombocytopenia is one of the most common hematological disease that can be life-threatening caused by bleeding complications. However, the treatment options for thrombocytopenia remain limited. METHODS: In this study, giemsa staining, phalloidin staining, immunofluorescence and flow cytometry were used to identify the effects of 3,3'-di-O-methylellagic acid 4'-glucoside (DMAG), a natural ellagic acid derived from Sanguisorba officinalis L. (SOL) on megakaryocyte differentiation in HEL cells. Then, thrombocytopenia mice model was constructed by X-ray irradiation to evaluate the therapeutic action of DMAG on thrombocytopenia. Furthermore, the effects of DMAG on platelet function were evaluated by tail bleeding time, platelet aggregation and platelet adhesion assays. Next, network pharmacology approaches were carried out to identify the targets of DMAG. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to elucidate the underling mechanism of DMAG against thrombocytopenia. Finally, molecular docking simulation, molecular dynamics simulation and western blot analysis were used to explore the relationship between DAMG with its targets. RESULTS: DMAG significantly promoted megakaryocyte differentiation of HEL cells. DMAG administration accelerated platelet recovery and megakaryopoiesis, shortened tail bleeding time, strengthened platelet aggregation and adhesion in thrombocytopenia mice. Network pharmacology revealed that ITGA2B, ITGB3, VWF, PLEK, TLR2, BCL2, BCL2L1 and TNF were the core targets of DMAG. GO and KEGG pathway enrichment analyses suggested that the core targets of DMAG were enriched in PI3K-Akt signaling pathway, hematopoietic cell lineage, ECM-receptor interaction and platelet activation. Molecular docking simulation and molecular dynamics simulation further indicated that ITGA2B, ITGB3, PLEK and TLR2 displayed strong binding ability with DMAG. Finally, western blot analysis evidenced that DMAG up-regulated the expression of ITGA2B, ITGB3, VWF, p-Akt and PLEK. CONCLUSION: DMAG plays a critical role in promoting megakaryocytes differentiation and platelets production and might be a promising medicine for the treatment of thrombocytopenia.

Evaluation of the Free Radical Scavenging Activities of Ellagic Acid and Ellagic Acid Peracetate by EPR Spectrometry.

The purpose of this study was to examine the free radical scavenging and antioxidant activities of ellagic acid (EA) and ellagic acid peracetate (EAPA) by measuring their reactions with the radicals, 2,2-diphenyl-1-picrylhydrazyl and galvinoxyl using EPR spectroscopy. We have also evaluated the influence of EA and EAPA on the ROS production in L-6 myoblasts and rat liver microsomal lipid peroxidation catalyzed by NADPH. The results obtained clearly indicated that EA has tremendous ability to scavenge free radicals, even at concentration of 1 µM. Interestingly even in the absence of esterase, EAPA, the acetylated product of EA, was also found to be a good scavenger but at a relatively slower rate. Kinetic studies revealed that both EA and EAPA have ability to scavenge free radicals at the concentrations of 1 µM over extended periods of time. In cellular systems, EA and EAPA were found to have similar potentials for the inhibition of ROS production in L-6 myoblasts and NADPH-dependent catalyzed microsomal lipid peroxidation.

Recent Advances in the Production and Applications of Ellagic Acid and Its Derivatives. A Review.

Ellagitannins (ETs), characterized by their diversity and chemical complexity, belong to the class of hydrolysable tannins that, via hydrolysis under acidic or alkaline conditions, can yield ellagic acid (EA). They are mostly found as a part of extractives in angiosperms. As known antioxidants and chelators, EA and EA derivatives are drawing an increasing interest towards extensive technical and biomedical applications. The latter ones include possible antibacterial, antifungal, antiviral, anti-inflammatory, hepato- and cardioprotective, chemopreventive, neuroprotective, anti-diabetic, gastroprotective, antihyperlipidemic, and antidepressant-like activities, among others. EA's synthesis and production challenges prompt further research on new methods and alternative sources. Conventional and prospective methods and raw materials for the production of EA and its derivatives are reviewed. Among the potential sources of EA, the residues and industrial streams of the pulp industry have been highlighted and considered as an alluring alternative in terms of commercial exploitation.

In Vitro Nephrotoxicity Induced by Herb-Herb Interaction between Radix Glycyrrhizae and Radix Euphorbiae Pekinensis.

Radix Glycyrrhizae (RG)-Radix Euphorbiae Pekinensis (REP) is a representative incompatible herbal pair of Eighteen Incompatible Medicaments (EIM) and has been disputed in clinical application for a long time. The present study was performed with the Madin-Darby canine kidney (MDCK) cell line using cell cytotoxicity assay, apoptosis detection, cell cycle measurement, reactive oxygen species (ROS) determination, and high content analysis (HCA) in combination with high-performance liquid chromatography (HPLC) fingerprint comparison to clarify whether RG and REP can be concomitantly used from the perspective of cytotoxicity, investigate the major correlated compounds, and elucidate the underlying mechanisms. The results showed that the toxicity of REP could be significantly enhanced through its concomitant use with RG in the ratio of 1 : 1, and this increased toxicity could be weakened with the further increased proportion of RG. 3,3'-di-O-methylellagic acid-4'-O-ß-D-xylopyranoside (DEAX) and 3,3'-di-O-methylellagic acid (DEA) were shown to be mainly responsible for the toxicity induced by concomitant use of REP and RG. Both RG-REP decoctions and the above two compounds boosted cell apoptosis, cellular morphological change, ROS accumulation, and mitochondrial membrane potential (MMP) disruption. In conclusion, the incompatible use of RG and REP is conditionally established because of the bidirectional regulatory effect of RG, and the major compounds responsible for RG-REP incompatibility are DEAX and DEA, which result in toxicity through activation of mitochondria-dependent apoptosis induced by increased ROS production. This study provided a basis for understanding the incompatible use of RG and REP and the EIM theory.

The antioxidant compounds isolated from the fruits of chinese wild raspberry Rubus Chingii Hu.

Raspberry, the fruit of Rubus Chingji Hu, is a widely distributed economic staple food in China. It has long been used as a traditional medicine in mainland China to treat kidney enuresis, nocturnal emission and premature ejaculation in clinic. In this paper, six known compounds (1 - 6) were purified from the fruits of Rubus chingji. Their structures were elucidated as (16α)-16,17-dihydroxy-ent-kauran-2-one17-O-ß-D-glucopyranoside (1), (16R) -16,17-dihydroxy-ent-kaurane-2-one (2), 3,3'-di-O-methylellagic acid 4-(5''-acetyl)-α-L-arabinofuranoside (3), quercilicoside A (4), esculetine (5) and ethyl-ß-D-glucoside (6). All the compounds were isolated from Rubus Chingji Hu for the first time. Compounds 3 and 5 shown distinctive free radical scavenging activities in DPPH and FRAP assays. In addition, no cytotoxicity was observed for compounds 3 and 5 against different cancer cells, suggesting that they might be useful as potential antioxidant agents against various reactive oxygen species.[Formula: see text].

Polyphenols from Euphorbia pekinensis Inhibit AGEs Formation In Vitro and Vessel Dilation in Larval Zebrafish In Vivo.

To identify active compounds in the roots of Euphorbia pekinensis for treatment of diabetic complications, an active column fraction from a 70% EtOH extract of E. pekinensis root was purified by preparative reversed-phase high-performance liquid chromatography, leading to the isolation of a new ellagic acid derivative, 3,3'-di-O-methylellagic acid 4-O-(6"-O-galloyl)-ß-D-galactopyranoside (1: ), along with three known compounds, geraniin (2: ), 3,3'-di-O-methylellagic acid 4-O-ß-D-xylopyranoside (3: ), and ellagic acid 3,3'-dimethyl ether (4: ). The structure of the new compound was established by extensive spectroscopic studies and chemical evidence. The inhibitory effects of isolated compounds 1: -4: on advanced glycation end-products (AGEs) formation were examined. All compounds exhibited considerable inhibition of AGEs formation and IC50 values of 0.41 - 12.33 µM, compared with those of the positive controls aminoguanidine (IC50 = 1122.34 µM) and quercetin (IC50 = 27.80 µM). In addition, the effects of 2: and 4: on the dilation of hyaloid-retinal vessels induced by high glucose (HG) in larval zebrafish were investigated; both compounds significantly reduced the HG-induced dilation of hyaloid-retinal vessels relative to the HG-treated control group.

A new coruleoellagic acid derivative from stems of Rhodamnia dumetorum.

A new coruleoellagic acid derivative, 3,3',4,4',5'-pentamethylcoruleoellagic acid (1) together with nine known compounds, hexamethylcoruleoellagic acid (2), 3,4,3'-tri-O-methylellagic acid (3), heptaphylline (4), 7-methoxymukonal (5), dentatin (6), sinapaldehyde (7), gallic acid (8), 2,6-dimethoxy-4H-pyran-4-one (9) and ß-sitosterol (10) were isolated from the stems of Rhodamnia dumetorum. Their structures were identified by physical and spectroscopic data (IR, 1D and 2D NMR, and MS). Compounds 1, 2 and 7-10 were tested for antibacterial activity against six pathogenic bacterial strains (Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Methicillin resistant S. aureus (MRSA)).

Improved Synthesis of Nigricanin.

An ellagic acid-related natural product, nigricanin (1), was synthesized via the Ullmann coupling reaction of 2-bromo-3,4-dialkoxybenzaldehyde (4) followed by the Cannizzaro reaction for desymmetrization of the symmetric biaryl compound (5). Compared to our previously reported study, the presented synthesis improved the sequence step number.

A Phenolic Extract Obtained from Methyl Jasmonate-Treated Strawberries Enhances Apoptosis in a Human Cervical Cancer Cell Line.

In the present study, we evaluated the effect of methyl jasmonate (MeJA) treatment on strawberry phenolic composition. Strawberry extracts contain a mixture of phenolic compounds possessing several biological properties. We demonstrated that these extracts were more effective in inducing apoptosis in HeLa cells compared to phenolic preparations derived from untreated strawberries. Treatment of strawberries with 0.5% MeJA resulted in increased polyphenols content (from 7.4 to 8.6 mM quercetin equivalents) and antioxidant properties (from 3.9 to 4.6 mM quercetin equivalents). The identification and quantification of phenolic compounds by liquid chromatography-mass spectrometry in the strawberry extracts showed that cyanidin glucoside, pelargonidin glucoside, and ellagic glucoside acid were significantly higher in strawberries treated with MeJA. Phenolic extracts from MeJA-treated strawberries significantly decreased the cell viability in HeLa cells, compared to extracts derived from untreated fruits. We hypothesized that the enhanced apoptotic activity of MeJA-treated strawberries was due to a synergistic or additive effect of different phenolic compounds present in the extract, rather than the activity of a single molecule.

Profiling of Gallic and Ellagic Acid Derivatives in Different Plant Parts of Terminalia arjuna by HPLC-ESI-QTOF-MS/MS.

Terminalia arjuna is a medicinal plant used in ethnomedicine and the codified traditional medicine. A number of active constituents are reported, but there is no information on the whole range of gallic and ellagic acid derivatives present in this plant A rapid and sensitive analytical method was developed using reverse phase high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS) for qualitative analysis to determine the array of bioactive phytochemicals and their variations in different plant parts viz. bark, unripe fruit, ripe fruit, leaf, root and stem. Separation was performed on a Thermo Betasil C8 column (250 mm x 4.5 mm, 5 µm) with a mobile phase consisted of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min in 55 min. A wide range of constituents of T. arjuna were characterized and broadly grouped as 27 gallic acid and 52 ellagic acid derivatives.

Compounds from Terminalli brownii Extracts with Toxicity against the Fish Pathogenic Bacterium Flavobacterium columnare.

The pond-raised channel catfish (Ictaluruspunctatus) industry in the United States of America can incur losses of over a $100 million annually due to bacterial diseases including columnaris disease caused by Flavobacterium columnare. One management approach available to catfish producers is the use of medicated- feed containing antibiotics. However, the negative attributes of antibiotic use in agriculture include public concerns and the potential development of antibiotic-resistant bacteria. Therefore, the discovery of environmentally-safe natural compounds for use as therapeutic agents would greatly benefit the catfish industry. In this study, a rapid bioassay was used to evaluate crude plant extracts as the first step in the discovery of natural therapeutants. Plant extracts from Terminalia brownii were found to be inhibitory towards F. columnare. The minimum inhibitory concentration (MIC) of the 5% water-methanol extract ofT. brownii (stem bark) was 10 µg/mL and the 24 h 50% inhibition concentration (IC(50)) was 40 pg/mL. Subsequent bioassay-guided fractionation of the T. brownR ethanol extract using reverse phase C-4 chromatography revealed the highest level of activity in the aqueous:methanol (50:50) fraction. HPLC analysis and subsequent purification of this fraction provided two compounds identified as ellagic acid (1) and 4-O-(3",4"-di-O-galloyl-a-L-rhamnopyrahosyl)ellagic acid (2). Compound 2 was the most active isolated compound, with a minimum inhibitory concentration (MIC) of 10±0 µg/mL and 24 h IC(50) of 31±1 µg/mL. Although 1 was more active according to a MIC of 6±5 µg/mL, its 24 h IC(50) was >100 µg/mL, and, therefore, it was less active overall of the two most active isolated compounds.

A Novel Ellagic Acid Derivative from Desbordesia glaucescens.

One novel ellagic acid derivative, desglauside (1), was isolated from the leaves of Desbordesia glaucescens together with three known compounds [3',4'-di-O-methylellagic acid (2), oleanolic acid (3) and ß-sitosterol-3-O-ß-D-glucopyranoside (4)]. Their structures were elucidated on the basis of NMR spectroscopic and MS analysis, and by comparison with related published data. The crude extract, fractions and isolated compounds showed no activity against four yeast strains [Candida albicans (ATCC 9002), C. parapsilopsis (ATCC22019), C. tropicalis (ATCC750), Cryptococcus neoformans (IP95026) and one isolate of Candida guilliermondii].

The ellagic acid derivative 4,4'-di-O-methylellagic acid efficiently inhibits colon cancer cell growth through a mechanism involving WNT16.

Ellagic acid (EA) and some derivatives have been reported to inhibit cancer cell proliferation, induce cell cycle arrest, and modulate some important cellular processes related to cancer. This study aimed to identify possible structure-activity relationships of EA and some in vivo derivatives in their antiproliferative effect on both human colon cancer and normal cells, and to compare this activity with that of other polyphenols. Our results showed that 4,4'-di-O-methylellagic acid (4,4'-DiOMEA) was the most effective compound in the inhibition of colon cancer cell proliferation. 4,4'-DiOMEA was 13-fold more effective than other compounds of the same family. In addition, 4,4'-DiOMEA was very active against colon cancer cells resistant to the chemotherapeutic agent 5-fluoracil, whereas no effect was observed in nonmalignant colon cells. Moreover, no correlation between antiproliferative and antioxidant activities was found, further supporting that structure differences might result in dissimilar molecular targets involved in their differential effects. Finally, microarray analysis revealed that 4,4'-DiOMEA modulated Wnt signaling, which might be involved in the potential antitumor action of this compound. Our results suggest that structural-activity differences between EA and 4,4'-DiOMEA might constitute the basis for a new strategy in anticancer drug discovery based on these chemical modifications.

A new ellagic acid derivative from Polygonum runcinatum.

A new ellagic acid derivative, 3,3'-dimethylellagic acid-4'-O-(6″-galloyl)-ß-D-glucoside, named runcinatside (5), together with four known compounds 3,3'-dimethylellagic acid (1), 3,3',4'-trimethylellagic acid (2), 3,3'-dimethylellagic acid-4'-O-ß-D-glucoside (3) and 3-methylellagic acid-4'-O-α-L-rhamno-pyranoside (4), was isolated from the roots of Polygonum runcinatum Buch.-Ham. ex D.Don Var. sinense Hemsl and the structures of these compounds were established by spectroscopic methods and comparison with previously reported data. All compounds showed antioxidant activities in vitro and compound 5 possessed the highest activity.

Two ellagic acids isolated from roots of Sanguisorba officinalis L. promote hematopoietic progenitor cell proliferation and megakaryocyte differentiation.

Using a bioassay-directed chromatographic separation, two ellagic acids were obtained from the ethyl acetate extract of the roots of Sanguisorba officinalis L. On the basis of chemical and spectroscopic methods, the two ellagic acids were identified as 3,3',4-tri-O-methylellagic acid-4'-O-ß-d-xyloside and 3,3',4-tri-O-methylellagic acid. Stimulation of cell proliferation was assayed in hematopoietic progenitor cells using the Cell Counting kit-8 method. The megakaryocyte differentiation was determined in human erythroleukemia (HEL) cells using Giemsa staining and flow cytometry analysis. The ellagic acids significantly stimulated the proliferation of Baf3/Mpl cells. Morphology analysis and megakaryocyte specific-marker CD41 staining confirmed that the ellagic acids induced megakaryocyte differentiation in HEL cells. This is the first time that 3,3',4-tri-O-methylellagic acid or 3,3',4-tri-O-methylellagic acid-4'-O-ß-d-xyloside are reported to induce megakaryopoiesis, suggesting a class of small molecules which differ from others non-peptidyl, and appears to have potential for clinical development as a therapeutic agent for patients with blood platelet disorders.

[Chemical constituents from Canarium pimela fruits].

OBJECTIVE: To investigate the chemical constituents from Canarium pimela fruits. METHODS: Compounds were obtained after separation and purification by silica gel and Sephadex LH-20. The structures were identified on the basis of physico-chemical properties and spectrum data. RESULTS: Eight compounds were isolated from Canarium pimela fruits. The structures were identified as amentoflavone (1), kaempferol-3-O-ß-D-galactopyranoside (2), shikimic acid (3), quercetin (4), kaempferol (5), 3,3'-di-O-methylellagic acid (6), 3,3',4-tri-O-methylellagic acid (7) and stigmasterol (8). CONCLUSION: Compounds 1-8 are isolated from Canarium pimela fruits for the first time.

Density functional predictions of antioxidant activity and UV spectral features of nasutin A, isonasutin, ellagic acid, and one of its possible derivatives.

The antioxidant ability of ellagic acid and some of its derivatives was explored at density functional level of theory within the framework of the following three different reaction mechanisms: hydrogen atom transfer (HAT), electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET). Computations were performed in gas phase and in both water and methanol media. Results show that the HAT mechanism is preferred by this class of compounds in all environments, although, in principle, polar solvents should promote the SET-PT and SPLET mechanisms. Among the considered compounds, the derivative not yet experimentally characterized seems to be the most promising candidate as antioxidant. For a more detailed spectroscopic characterization and to help in the identification of these compounds, the simulated UV spectra of all investigated molecules were done by using the time-dependent formulation of density functional theory (TDDFT).

Synthesis of okicamelliaside, a glucoside of ellagic acid with potent anti-degranulation activity.

Okicamelliaside, a glucoside of ellagic acid with potent anti-degranulation activity, was synthesized from ellagic acid. The regioselectivity, solubility, and high reactivity of the intermediates throughout the synthesis were obtained by the complementary use of triisopropylsilyl (TIPS) and methoxyethoxymethyl (MEM) protective groups on the aglycone skeleton.

A comparative study of anti-Candida activity and phenolic contents of the calluses from Lythrum salicaria L. in different treatments.

In the study, anti-Candida activity and phenol contents of Lythrum salicaria L. calli and wild species have been evaluated. The seeds of L. salicaria (Lythraceae), collected from Lahidjan City in the north of Iran, were cultured in Murashige and Skoog medium (MSM) with a supplement, gibberellin, to germinate. Callus inductions were performed from segments of seedling on MSM containing different concentrations of plant growth regulators, 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The activity of calluses extracts, wild plant, gallic acid, and 3,3',4'-tri-O-methylellagic acid-4-O-ß-D-glucopyranoside (TMEG) as the main phenolic compounds against Candida albicans was assessed using cup plate diffusion method. The total phenols contents of calli and wild plant extracts were analyzed using Folin-Ciocalteu reagent. The callus formation in MSM supplemented with various concentrations of 2,4-D and BAP were 0-100 %. Anti-Candida activity of callus extract which obtained from MSM supplemented with 2,4-D and BAP (1 mgdm(-3)) was similar to the wild plant extract. Minimum inhibitory concentration values of gallic acid and TMEG were obtained as 0.312 and 2.5 mgcm(-3), respectively. Gallic acid equivalent values in all treatments were from 0 to 288 µg GAE mg(-1). Phenolic contents of plant aerial parts (331±3.7 µg GAE mg(-1)) and the callus, which developed in MSM including 1 mgdm(-3) of both 2,4-D and BAP, showed the same phenolic value and exhibited anti-Candida extract activity.