ECKOLS, NOVEL PHLOROTANNINS WITH A DIBENZO-<i>p</i>-DIOXIN SKELETON POSSESSING INHIBITORY EFFECTS ON α2-MACROGLOBULIN FROM THE BROWN ALGA <i>ECKLONIA KUROME</i> OKAMURA

Fukuyama, Yoshiyasu; Miura, Iwao; Kinzyo, Ziunei; Mori, Hideo; Kido, Masaru; Nakayama, Yasuo; Takahashi, Masayuki; Ochi, Masamitsu

doi:10.1246/cl.1985.739

Cited by 46 publications

(38 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Eisenine, biotin, and laminine are known components of this species 12) and eckol (1), 8,8Ј-bieckol (2), and phlorofucofuroeckol A (4) have been isolated from Ecklonia kurome OKAMURA as antiplasmin inhibitors. [8][9][10] Recently, it has been reported that phlorotannins from Ecklonia species are radical scavengers. 13,14) In this report, four phlorotannin compounds (1-4) containing the dibenzo [1,4]dioxin element as the core structure were isolated from E. cava and their inhibitory activities against HIV-1 RT and protease were evaluated.…”

Section: Discussionmentioning

confidence: 99%

“…The structures of these compounds were determined by comparison of UV, MS, and 1 H-and 13 C-NMR data with reported values. [8][9][10][11] Inhibitory Effects on HIV-1 RT and Protease Inhibitory activities of these compounds against HIV-1 RT and protease are shown in Table 1. 8,8Ј-Bieckol (2) and 8,4ٞ-dieckol (3) strongly inhibited HIV-1 RT activity, whereas eckol (1) and phlorofucofuroeckol A (4) did not exhibit inhibitory activity against this enzyme.…”

Section: Isolation Of Phlorotannins From E Cavamentioning

confidence: 99%

See 1 more Smart Citation

Inhibition of HIV-1 Reverse Transcriptase and Protease by Phlorotannins from the Brown Alga Ecklonia cava

Ahn

Yoon

Min

et al. 2004

Biological & Pharmaceutical Bulletin

231

103

View full text Add to dashboard Cite

The reverse transcriptase (RT) of human immunodeficiency virus type-1 (HIV-1) converts the single-stranded (ϩ) viral RNA genome into a double-stranded proviral DNA prior to its integration into the host genomic DNA. The RT is a multifunctional enzyme with three recognized enzymatic activities of RNA-dependent DNA polymerase (RDDP), DNA-dependent DNA polymerase (DDDP), and ribonuclease H activities. HIV-1 protease is an aspartic protease required for the proteolytic processing of the large Gag and Gag-Pol viral polyprotein precursors into the mature virion structural proteins, as well as the virion enzymes. These two enzymes, HIV-1 RT and protease, have key roles in HIV replication and inhibition of these enzymes along with HIV-1 integrase has been a major target of acquired immunodeficiency syndrome (AIDS) therapy. 1)In addition to the well-known nucleoside RT inhibitors (NRTIs), zidovudine (AZT), didanosine (ddC), zalcitabine (ddT), stavudine (d4T), lamivudine (3TC), and abacavir (ABC), non-nucleoside RT inhibitors (NNRTIs), such as nevirapine, delavirdine, and efavirenz have been formally approved to treat HIV infection. On the other hand, saquinavir, ritonavir, and indinavir are the three main HIV protease inhibitors available today. A number of inhibitors interacting with RT have been isolated from plants (baicalin, avarol, avarone, and psychotrine) and marine resources (illimaquinone, peyssonol, and KM043). [2][3][4] In the case of HIV-1 protease, natural products, such as mangostin, ursolic, and maslinic acid, have been reported to show inhibitory activity against this enzyme. 5) We previously reported the results of screening inhibitory activities of 47 types of Korean seaweed on HIV-1 RT and found that the EtOAc fraction of Ecklonia cava strongly inhibited the RDDP activity of this enzyme. 6) In this study, we report the isolation of four phlorotannin compounds containing dibenzo [1,4]dioxin elements in common from E. cava and the kinetic study of HIV-1 RT by 8,8Ј-bieckol (2) that showed the most potent inhibitory effect on this enzyme. MATERIALS AND METHODS MaterialsThe thalli of E. cava KJELLMAN were collected from the coasts of Korea including Sungsanpo, Wando, and Namhaedo from January 1999 to June 2000. After cleaning the surface of the thalli with water to remove visible epiphytes and dirt, samples were dried at 60°C for 12 h in an oven and then ground in a coffee grinder. This seaweed was identified by Prof. S. M. Boo of the Department of Biology, Chungnam National University, Korea, and Prof. Y. S. Oh of the Department of Aquaculture, Gyeongsang National University, Korea. A voucher specimen (SSI-06) was deposited in the Herbarium of the Department of Biological Sciences, Sungkyunkwan University.Extraction and Isolation The dried thalli (1 kg) of E. cava were extracted three times with 100% MeOH and evaporated in vacuo. The MeOH extract (180 g) was dissolved in water and partitioned with n-hexane. After the H 2 O layer was further partitioned with ethyl acetate, the organic solvent fraction was c...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Isolation Of Phlorotannins From E Cavamentioning

confidence: 99%

Inhibition of HIV-1 Reverse Transcriptase and Protease by Phlorotannins from the Brown Alga Ecklonia cava

Ahn

Yoon

Min

et al. 2004

Biological & Pharmaceutical Bulletin

231

103

View full text Add to dashboard Cite

show abstract

“…These algae are known to contain several phlorotannins, viz., eckol, 1) dieckol, 1) 6,6 0 -bieckol, 2) 8,8 0 -bieckol, 2) and phlorofucofuroeckol-A (PFF-A). 3) Phlorotannins have been reported to have certain biological activities, such as antioxidation, 4) bactericide, 5) anti-cancer, 6) anti-diabetic complications, 7,8) and chemoprevention against several vascular diseases.…”

mentioning

confidence: 99%

Isolation of a New Anti-Allergic Phlorotannin, Phlorofucofuroeckol-B, from an Edible Brown Alga,Eisenia arborea

Sugiura

Matsuda

Yamada

et al. 2006

Bioscience, Biotechnology, and Biochemistry

123

View full text Add to dashboard Cite

“…1). [5][6][7][8] Compound 1 was obtained as off-white amorphous powder. The molecular formula of 1 was determined as C 18 .…”

mentioning

confidence: 99%

A New Phlorotannin from the Brown Alga Ecklonia stolonifera

et al. 2003

View full text Add to dashboard Cite

Ecklonia stolonifera OKAMURA is a member of the family of Laminariaceae, belonging to the order Laminariales as a perennial brown alga. The previous phytochemical investigations performed on this species resulted in the isolation of phloroglucinol, 1) phlorotannins 2) and ecklonialactones. 3,4) In the course of a continuous study on the active principles of this alga, we isolated a new phlorotannin with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, along with three known ones, of the methanolic extract of E. stolonifera. Column chromatography of the EtOAc soluble part from the methanolic extract of this alga yielded four phlorotannins, compounds 1-4 in the order of increasing polarity. The structures of 2, 3, and 4 were identified by comparison with published spectral data as eckol, phlorofucofuroeckol A, and dieckol, respectively (Fig. 1). [5][6][7][8] Compound 1 was obtained as off-white amorphous powder. The molecular formula of 1 was determined as C 18 . The carbon-13 nuclear magnetic resonance ( 13 C-NMR) spectrum of 1 indicated the presence of five non-substituted and thirteen O-bearing aromatic carbons, whereas the proton nuclear magnetic resonance ( 1 H-NMR) spectrum contained signals characteristic of five aromatic protons, i.e. two AB systems at d 6.04 (1H, Jϭ2.7 Hz) and 5.82 (1H, Jϭ2.7 Hz), and d 6.01 (1H, Jϭ2.7 Hz) and 5.84 (1H, Jϭ2.7 Hz), and a singlet at 6.10 (1H) as well as five singlets indicating phenolic hydroxy protons at d 9.77, 9.64, 9.60, 9.27, and 9.26. These NMR spectral features are very similar to those of eckol (2) isolated from Eisenia bicyclis and Ecklonia kurome, 5,6) indicating that 1 is composed of three phloroglucinol units. The only difference between the 1 H-NMR spectra of 1 and 2 is that the former lacks the signals for one phenolic hydroxyl proton and one aromatic proton, suggesting that 1 has an additional aryl-ether linkage. This was supported by the presence of a new oxygen-bearing carbon signal (d 122.7), which is characteristic of an aromatic carbon with two oxygenated neighbors, and also by the formation of a pentaacetate (1a) on usual acetylation. Analysis of HMQC, HMBC and NOESY spectra of 1 allowed an unambiguous assignment of all the proton and carbon signals (Table 1, Fig. 2). In the HMBC spectrum, each cross peak between d 9.77 and C-1 (d 146.1), C-2 (d 98.8), and C-14a , and C-10 (d 98.8) designated the existence of the hydroxyl groups at C-11 and C-9, respectively. Each cross peak between d 9.60 and C-5a (d 125.9), C-6 (d 140.1), and C-7 (d 97.6), established the presence of the hydroxyl group at C-6. The stereostructure of compound 1 was deduced to be planar and achiral by its specific rotation and a loss of additional anisotropic effect for the aromatic protons. It was found that specific rotation showed zero value and the similar chemical shifts not only between H-2 and H-10, but also between H-4 and H-12. Consequently, the structure of 1 was established as 5,8,13,14-tetraoxa-pentaphene-1,3,6,9,11-pentaol, named eckstolonol. Compounds 1-...

show abstract

ECKOLS, NOVEL PHLOROTANNINS WITH A DIBENZO-p-DIOXIN SKELETON POSSESSING INHIBITORY EFFECTS ON α2-MACROGLOBULIN FROM THE BROWN ALGA ECKLONIA KUROME OKAMURA

Cited by 46 publications

References 6 publications

Inhibition of HIV-1 Reverse Transcriptase and Protease by Phlorotannins from the Brown Alga Ecklonia cava

Inhibition of HIV-1 Reverse Transcriptase and Protease by Phlorotannins from the Brown Alga Ecklonia cava

Isolation of a New Anti-Allergic Phlorotannin, Phlorofucofuroeckol-B, from an Edible Brown Alga,Eisenia arborea

A New Phlorotannin from the Brown Alga Ecklonia stolonifera

Contact Info

Product

Resources

About