- Biosynthesis of Actinorhodin and Related Antibiotics: Discovery of Alternative Routes for Quinone Formation Encoded in the act Gene Cluster
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All known benzoisochromanequinone (BIQ) biosynthetic gene clusters carry a set of genes encoding a two-component monooxygenase homologous to the ActVA-ORF5/ActVB system for actinorhodin biosynthesis in Streptomyces coelicolor A3(2). Here, we conducted molecular genetic and biochemical studies of this enzyme system. Inactivation of actVA-ORF5 yielded a shunt product, actinoperylone (ACPL), apparently derived from 6-deoxy-dihydrokalafungin. Similarly, deletion of actVB resulted in accumulation of ACPL, indicating a critical role for the monooxygenase system in C-6 oxygenation, a biosynthetic step common to all BIQ biosyntheses. Furthermore, in vitro, we showed a quinone-forming activity of the ActVA-ORF5/ActVB system in addition to that of a known C-6 monooxygenase, ActVA-ORF6, by using emodinanthrone as a model substrate. Our results demonstrate that the act gene cluster encodes two alternative routes for quinone formation by C-6 oxygenation in BIQ biosynthesis.
- Okamoto, Susumu,Taguchi, Takaaki,Ochi, Kozo,Ichinose, Koji
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- Optimized protocol for multigram preparation of emodin anthrone, a precursor in the hypericin synthesis
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Emodin reduction to emodin anthrone comprise one of three process steps involved in the hypericin synthesis, a powerful natural photosensitiser found in plants of the genus Hypericum. In this communication, an optimized protocol was established for emodin reduction enabling an efficient multigram preparation of emodin anthrone. A screening of reducing agent (SnCl2·2H2O and HClconc) under different reaction times was employed in micro-scale and monitored by electronic absorption spectroscopy technique. Data showed lower yields of emodin anthrone when some experimental conditions previously described in the literature were reproduce. However, using the optimized protocol for the emodin reduction these yields were overcoming, and a gram-scale supply experiment was reproducible for the preparation of 10 grams of emodin anthrone with excellent yield.
- Gon?alves, Renato Sonchini,César, Gabriel Batista,Barbosa, Patrícia Magalh?es,Hioka, Noboru,Nakamura, Celso Vataru,Bruschi, Marcos Luciano,Caetano, Wilker
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- Accumulation and Photocytotoxicity of Hypericin and Analogs in Two- and Three-Dimensional Cultures of Transitional Cell Carcinoma Cells
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The aim of this study was to investigate the in vitro cellular accumulation, distribution and photocytotoxic effect of hypericin in two-dimensional (2-D) and three-dimensional (3-D) cultured RT-112 transitional cell carcinoma cells of the bladder. In addition, two iodinated derivatives of hypericin were incorporated to investigate whether these analogs, with their increased lipophilicity and heavy-atom effect, display a different biological behavior and optimized photodynamic effect. The results indicate that hypericin and mono-iodohypericin behave similarly in terms of cellular accumulation, spheroidal distribution and photocytotoxic effect. In contrast, di-iodohypericin concentrated to a higher extent in monolayers and spheroids, but the accumulation was restricted to the outermost part of the spheroid. An inverse correlation therefore seems to exist between the extent of cellular uptake under 2-D conditions and the penetration of the compounds in multicellular systems. Moreover, a less pronounced photocytotoxic effect was observed for di-iodohypericin in both 2-D and 3-D cell culture systems. It can be concluded that iodinated derivatives of hypericin do not show an increased cytotoxic effect upon irradiation in either monolayers or spheroids. Moreover, this study shows that when new photosensitizers are preclinically developed, the use of 3-D cell aggregates is critical for a correct evaluation of their efficacy.
- Huygens, Ann,Huyghe, Dieter,Bormans, Guy,Verbruggen, Alfons,Kamuhabwa, Appolinary R.,Roskams, Tania,De Witte, Peter A. M.
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- Highly efficient green synthesis and photodynamic therapeutic study of hypericin and its derivatives
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A highly efficient synthetic pathway for hypericin (7a) was achieved under mild conditions with an overall yield over two steps of 92% using emodinanthrone as a starting material, where protohypericin, a key precursor of hypericin, was synthesized in water with microwave assistance, which was then photocyclized to hypericin with a high yield via 1 h irradiation in a visible light reactor equipped with 575 nm monochromatic lamps. In addition, the method could be used to synthesize hypericin derivatives (7b-d) with similar overall yields. Furthermore, their effects of photodynamic therapy (PDT) were evaluated on A431, HepG-2, and MCF-7 cell lines. The PDT of 7b was better than that of 7a, whereas 7c and 7d were worse. Unlike other cell lines, MCF-7 was not sensitive to any of 7a-d at the same concentrations.
- Zhang, Ying,Shang, Kun,Wu, Xiaowen,Song, Siyu,Li, Zebo,Pei, Zhichao,Pei, Yuxin
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- An Efficient Multigram Synthesis of Hypericin Improved by a Low Power LED Based Photoreactor
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In this work, an improved synthesis process was developed for the multigram production of hypericin. An inexpensive and efficient low power Light Emission Diode (LED) based photoreactor was designed and employed to perform the protohypericin photocyclization reaction allowing its photoconversion in hypericin. This closed system overcomes safety issues related to scale-up hypericin preparation typically described in the literature which combines the use of open systems, organic solvents, and high-power light sources. The photoreactor designed allows a solution to, mainly, the intrinsic effect of hypericin photobleaching inherent to the protohypericin photocyclization reaction, implying an increase in the yield of the final product and consequently the final cost. Using a red-LED based photoreactor, a safety protocol was carried out in a 5-g scale hypericin preparation with quantitative yield.
- Gon?alves, Renato S.,Rabello, Bruno R.,César, Gabriel B.,Pereira, Paulo C. S.,Ribeiro, Marcos A. S.,Meurer, Eduardo C.,Hioka, Noboru,Nakamura, Celso V.,Bruschi, Marcos L.,Caetano, Wilker
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- Investigation of the absorption of hypericin into the skin of hairless mice
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The skin absorption of hypericin was evaluated in hairless mice to develop an optimised hypericin topical formulation that could be used in the clinical study of psoriasis. Hypericin (0.01-1.0%) in Beeler basis, polyethylene glycol ointment, carbopol gel, cetomacrogol cream, petrolatum or emulsifying ointment, with and without skin-absorption enhancers (isopropylidene glycerol and diethylene glycol monoethyl ether), was tested in-vivo on hairless mice skin. Using a skin-stripping technique and the intrinsic fluorescence of hypericin under standardised UV365 irradiation, it was demonstrated that the absorption of hypericin very much depended on the vehicle used. The concentrations of hypericin in the skin were then estimated by HPLC analysis. For this purpose, two vehicles were employed, with which hypericin penetrated the skin of hairless mice well (emulsifying ointment with isopropylidene glycerol) or very poorly (polyethylene glycol ointment). In the case of emulsifying ointment with isopropylidene glycerol (0.05% hypericin), a substantial concentration of hypericin (8.6±3.2 μg g-1) (mean±s.d., n=5) was found in the skin. With polyethylene glycol ointment, however, only a limited hypericin skin concentration (0.38±0.34 μg g-1, n= 5) was achieved. These results show that emulsifying ointment with polyethylene glycol holds promise as an effective topical vehicle for the treatment of skin diseases, such as psoriasis, with hypericin.
- Kamuhabwa, Appolinary R.,Geboes, Karel R.,De Witte, Peter A.
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- A Convenient Semisynthetic Route to Hypericin
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A semisynthetic route to produce hypericin was established using Cortex frangulae as the starting point.The emodin isolated from it easily and in good yield was reduced to emodin anthrone by means of SnCl2.The latter was reacted via a known oxidative dimerization and photocyclization reaction into hypericin. Keywords: Emodin; Emodin anthrone; Hypericin; Cortex frangulae.
- Falk, H.,Meyer, J.,Oberreiter, M.
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- Effects of skeleton structure on necrosis targeting and clearance properties of radioiodinated dianthrones
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Necrosis avid agents (NAAs) can be used for diagnose of necrosis-related diseases, evaluation of therapeutic responses and targeted therapeutics of tumor. In order to probe into the effects of molecular skeleton structure on necrosis targeting and clearance properties of radioiodinated dianthrones, four dianthrone compounds with the same substituents but different skeletal structures, namely Hypericin (Hyp), protohypericin (ProHyp), emodin dianthrone mesomer (ED-1) and emodin dianthrone raceme (ED-2) were synthesized and radioiodinated. Then radioiodinated dianthrones were evaluated in vitro for their necrosis avidity in A549 lung cancer cells untreated and treated with H2O2. Their biodistribution and pharmacokinetic properties were determined in rat models of induced necrosis. In vitro cell assay revealed that destruction of rigid skeleton structure dramatically reduced their necrosis targeting ability. Animal studies demonstrated that destruction of rigid skeleton structure dramatically reduced the necrotic tissue uptake and speed up the clearance from the most normal tissues for the studied compounds. Among these 131I-dianthrones, 131I-Hyp exhibited the highest uptake and persistent retention in necrotic tissues. Hepatic infarction could be clearly visualized by SPECT/CT using 131I-Hyp as an imaging probe. The results suggest that the skeleton structure of Hyp is the lead structure for further structure optimization of this class of NAAs.
- Zhang, Dongjian,Jiang, Cuihua,Yang, Shengwei,Gao, Meng,Huang, Dejian,Wang, Xiaoning,Shao, Haibo,Feng, Yuanbo,Sun, Ziping,Ni, Yicheng,Zhang, Jian,Yin, Zhiqi
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- Tautomers of anthrahydroquinones: Enzymatic reduction and implications for chrysophanol, monodictyphenone, and related xanthone biosyntheses
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Reduction of emodin by sodium dithionite resulted in the formation of two tautomeric forms of emodin hydroquinone. Subsequent conversion by the short-chain dehydrogenase/reductase (SDR) MdpC into the corresponding 3-hydroxy-3,4-dihydroanthracen-1(2H)-one implies that deoxygenation is the first step in monodictyphenone biosynthesis. Implications for chrysophanol formation as well as reaction sequences in the related xanthone, ergochrome, and bianthraquinone biosyntheses are discussed.
- Schaetzle, Michael A.,Husain, Syed Masood,Ferlaino, Sascha,Mueller, Michael
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- 1,8-Substituted anthraquinones, anthrones and bianthrones as potential non-azole leads against fungal infections
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The synthesis of a variety of 1,8-substituted anthraquinones, anthrones and bianthrones and their potential as antifungal agents is evaluated. Preliminary screening against Schizosaccharomyces pombe (S. pombe), a fission yeast, and Saccharomyces cerevisiae (S. cerevisiae), a budding yeast, is reported. Both these yeast species demonstrate close homologue to a number of pathogenic fungi.
- Jalab, Murhaf,Critchley, Megan E.,Taylor, Charlotte M.,Lawrence, Clare L.,Smith, Robert B.
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- Clamping device anthraquinone compound in the preparation of antineoplastic application
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The invention relates to application of dianthraquinonyl, in particular to application of dianthraquinonyl compounds to preparing anti-tumor medicine. Radioactive therapeutic nuclides are labeled on dianthraquinonyl medicine, and accordingly the labeled medicine with excellent tumor targeting can be obtained. The application has the advantages that the compounds can be gathered on dead cells and tissues in tumors and are provided with instable chemical elements or isotopes, accordingly, radiation can occur, surrounding cells and tissues can be destroyed, and the purpose of treating tumors can be achieved.
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Paragraph 0043; 0044; 0045
(2019/01/14)
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- Design and synthesis of emodin derivatives as novel inhibitors of ATP-citrate lyase
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Aberrant cellular metabolism drives cancer proliferation and metastasis. ATP citrate lyase (ACL) plays a critical role in generating cytosolic acetyl CoA, a key building block for de novo fatty acid and cholesterol biosynthesis. ACL is overexpressed in ca
- Koerner, Steffi K.,Hanai, Jun-ichi,Bai, Sha,Jernigan, Finith E.,Oki, Miwa,Komaba, Chieko,Shuto, Emi,Sukhatme, Vikas P.,Sun, Lijun
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p. 920 - 928
(2016/12/23)
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- Hypericin synthesis method
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The invention provides a hypericin synthesis method. The hypericin synthesis method includes the steps of firstly, mixing emodin, glacial acetic acid and stannous chloride dihydrate prior to heating reflux, adding concentrated hydrochloric acid prior to cooling and filtering, washing a filtered product until the filtered product is neutral, and drying the neutral filtered product so as to obtain emodin anthrone; mixing the emodin anthrone, pyridine, piperidine, pyridine N-oxide and ferrous sulfate prior to reflux reaction, performing pressure reduction to recover the pyridine prior to cooling, adding hydrochloric acid for neutralizing prior to filtering, washing a filtered product until the filtered product is neutral, and drying the neutral filtered product so as to obtain protohypericin; dissolving the protohypericin into a sodium hydroxide solution, reacting under the action of lighting, and adding hydrochloric acid for neutralizing prior to suction filtration, washing and drying so as to obtain hypericin. The hypericin synthesis method has the advantages that the hypericin is prepared from the emodin through chemical synthesis and is synthesized through a process route including reduction, condensation and lighting reaction, and accordingly the method is high in yield, low in cost, simple and convenient to operate, high in hypericin chemical synthesis route applicability and suitable for enlarged production.
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Paragraph 0032; 0036; 0040; 0044; 0048
(2017/08/28)
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- Synthesis and Evaluation of 131I-Skyrin as a Necrosis Avid Agent for Potential Targeted Radionuclide Therapy of Solid Tumors
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An innovative anticancer approach targeted to necrotic tissues, which serves as a noncancerous and generic anchor, may present a breakthrough. Necrosis avid agents with a flat conjugate aromatic structure selectively accumulate in necrotic tissues, but they easily form aggregates that undesirably distribute to normal tissues. In this study, skyrin, a dianthraquinone compound with smaller and distorted -cores and thus decreased aggregates as compared with hypericin (Hyp), was designed to target necrosis for tumor therapy. Aggregation studies of skyrin by UV/vis spectroscopy showed a smaller self-association constant with skyrin than with Hyp. Skyrin was labeled by iodine-131 with a radiochemical purity of 98% and exhibited good stability in rat serum for 72 h. In vitro cell uptake studies showed significant difference in the uptake of 131I-skyrin by necrotic cells compared to normal cells (P 131I-skyrin in necrotic liver and muscle (p 131I-Hyp. In mice bearing H22 tumor xenografts treated with combretastatin A4 disodium phosphate, the highest uptake of 131I-skyrin was found in necrotic tumor. In conclusion, 131I-skyrin appears a promising agent with reduced accumulation in nontarget organs for targeted radionuclide therapy of solid tumors.
- Wang, Cong,Jin, Qiaomei,Yang, Shengwei,Zhang, Dongjian,Wang, Qin,Li, Jindian,Song, Shaoli,Sun, Ziping,Ni, Yicheng,Zhang, Jian,Yin, Zhiqi
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p. 180 - 189
(2016/01/15)
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- In vitro formation of the anthranoid scaffold by cell-free extracts from yeast-extract-treated Cassia bicapsularis cell cultures
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The anthranoid skeleton is believed to be formed by octaketide synthase (OKS), a member of the type III polyketide synthase (PKS) superfamily. Recombinant OKSs catalyze stepwise condensation of eight acetyl units to form a linear octaketide intermediate which, however, is incorrectly folded and cyclized to give the shunt products SEK4 and SEK4b. Here we report in vitro formation of the anthranoid scaffold by cell-free extracts from yeast-extract-treated Cassia bicapsularis cell cultures. Unlike field- and in vitro-grown shoots which accumulate anthraquinones, cell cultures mainly contained tetrahydroanthracenes, formation of which was increased 2.5-fold by the addition of yeast extract. The elicitor-stimulated accumulation of tetrahydroanthracenes was preceded by an approx. 35-fold increase in OKS activity. Incubation of cell-free extracts from yeast-extract-treated cell cultures with acetyl-CoA and [2-14C]malonyl-CoA led to formation of torosachrysone (tetrahydroanthracene) and emodin anthrone, beside two yet unidentified products. No product formation occurred in the absence of acetyl-CoA as starter substrate. To confirm the identities of the enzymatic products, cell-free extracts were incubated with acetyl-CoA and [U- 13C3]malonyl-CoA and 13C incorporation was analyzed by ESI-MS/MS. Detection of anthranoid biosynthesis in cell-free extracts indicates in vitro cooperation of OKS with a yet unidentified factor or enzyme for octaketide cyclization.
- Abdel-Rahman, Iman A.M.,Beuerle, Till,Ernst, Ludger,Abdel-Baky, Afaf M.,Desoky, Ezz El-Din K.,Ahmed, Amany S.,Beerhues, Ludger
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- A facile synthesis of emodin derivatives, emodin carbaldehyde, citreorosein, and their 10-deoxygenated derivatives and their inhibitory activities on μ-calpain
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A new procedure for the preparation of emodin carbaldehyde and citreorosein was described, in which, ω,ω'-dibromomethylemodin triacetate was prepared as a key intermediate by NBSmediated bromination of 1,3,8-triacetylemodin. Reduction of emodin and citreorosein with SnCl 2 in a 1:1 mixture of HOAc and HCl afforded the corresponding anthrones in 90% and 92% yield, respectively, while the corresponding 10-desoxyemodin carbaldehyde was prepared by MnO2 oxidation of 10-desoxycitreorosein. 10-Desoxycitreorosein and emodin carbaldehyde showed feasible μ-calpain inhibitory activities with IC50 values of 20.15 and 25.77 M, respectively.
- Liang, Jing Lu,Cha, Hyo Chang,Lee, Seung Ho,Son, Jong-Keun,Chang, Hyeun Wook,Eom, Ji-Eun,Kwon, Youngjoo,Jahng, Yurngdong
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experimental part
p. 447 - 454
(2012/08/08)
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- METHODS FOR PREPARING HYPERICIN
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The present invention provides a method for making hypericin comprising the steps of converting a protohypericin to a protohypericin salt, and irradiating the protohypericin salt with visible light to form hypericin. The present invention also provides an apparatus comprising a transparent column having a top end and a bottom end, an inlet attached to the column at the top end to flow reactants into the column, a container attached to the column at the bottom end; and a visible light source positioned to cast light on to the column. The present invention further provides a method for making hypericin using said apparatus.
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Page/Page column 9
(2011/04/19)
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- Cytotoxicity of rhamnosylanthraquinones and rhamnosylanthrones from Rhamnus nepalensis
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An extract of the fruits of Rhamnus nepalensis collected in Hoa Binh Province, Vietnam, was cytotoxic to KB cells. A bioassay-guided fractionation led to the isolation of a series of known anthraquinones and anthrones, one new rhamnosylanthraquinone, 3′-O-acetylfrangulin A (8), several new rhamnosylanthrones, the prinoidin-emodin bianthrones (9A-D), the prinoidin bianthrones (10A,B), and the rhamnepalins (11A-C). A structure-cytotoxic activity relationship study was performed on these isolates and some semisynthetic derivatives.
- Le Phuong Mai,Gueritte,Dumontet,Mai Van Tri,Hill,Thoison,Guenard,Sevenet
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p. 1162 - 1168
(2007/10/03)
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