Phorbas Sp Research Articles

Ansellone J, a Potent in Vitro and ex Vivo HIV-1 Latency Reversal Agent Isolated from a Phorbas sp. Marine Sponge.

Five new minor sesterterpenoids, ansellones H (4), I (5), J (6), and K (7) and phorone C (8), have been isolated from a Phorbas sp. marine sponge collected in British Columbia. Their structures have been elucidated by detailed analysis of NMR and MS data. Ansellone J (6) and phorone C (8) are potent in vitro HIV-1 latency reversal agents that are more potent than the reference compound and control protein kinase C activator prostratin (3). The most potent Phorbas sesterterpenoid, ansellone J (6), was evaluated for HIV latency reversal in a primary cell context using CD4+ T cells obtained directly from four combination antiretroviral therapy-suppressed donors with HIV. To a first approximation, ansellone J (6) induced HIV latency reversal at levels similar to prostratin (3) ex vivo, but at a 10-fold lower concentration.

Antibiofilm Activity of Phorbaketals from the Marine Sponge Phorbas sp. against Staphylococcus aureus.

Biofilm formation by Staphylococcus aureus plays a critical role in the persistence of chronic infections due to its tolerance against antimicrobial agents. Here, we investigated the antibiofilm efficacy of six phorbaketals: phorbaketal A (1), phorbaketal A acetate (2), phorbaketal B (3), phorbaketal B acetate (4), phorbaketal C (5), and phorbaketal C acetate (6), isolated from the Korean marine sponge Phorbas sp. Of these six compounds, 3 and 5 were found to be effective inhibitors of biofilm formation by two S. aureus strains, which included a methicillin-resistant S. aureus. In addition, 3 also inhibited the production of staphyloxanthin, which protects microbes from reactive oxygen species generated by neutrophils and macrophages. Transcriptional analyses showed that 3 and 5 inhibited the expression of the biofilm-related hemolysin gene hla and the nuclease gene nuc1.

Characterisation of a thermostable and proteolysis resistant phytase from Penicillium polonicum MF82 associated with the marine sponge Phorbas sp.

Phytases are widely used in human and animal nutrition, aquaculture, soil amendment, and in the production of lower myo-inositol phosphates for clinical purposes. Some of these applications, especially feed industry require robust enzymes. Since the marine environments are less studied compared to terrestrial environments, we evaluated the extracellular phytase activity of 110 marine derived filamentous fungal (MDFF) strains previously isolated from sponge and sediment samples of the Turkey. MDFF strains were qualitatively screened for their extracellular phytase activities and P. polonicum MF82 phytase was further characterized following partial purification. Optimum pH and temperature were determined as 5.5 and 60 °C respectively. A significant relative phytase activity was observed in the presence of urea and acetone. However, there was no phytase activity followed by the treatment with Triton X-100 and Tween 80. Characterization studies revealed that P. polonicum MF82 phytase has superior properties for industrial use including wide pH and temperature range for activity, high optimum activity temperature, high thermal and pH stability, resistance to many enzyme inhibitors including various heavy metals, denaturants, detergents, proteases and organic solvents. Phytase extracellularly produced by P. polonicum MF82 strain presents a good candidate for commercial applications. This study demonstrates that the MDFF strains are prolific sources for phytase and presents the first report about the production and characterization of the phytase from a marine-derived P. polonicum strain.

Total synthesis and structural revision of (+)-muironolide a.

Muironolide A is a fascinating tetrachlorinated marine polyketide isolated from the sponge of Phorbas sp. Only 90 μg had been isolated, and the structure was established by nanoscale NMR techniques. Herein we report the total synthesis of the substance with the assigned structure of muironolide A, propose a revised structure based on NMR data, and complete the enantioselective total synthesis of muironolide A.

Inhibition of yeast-to-hypha transition in Candida albicans by phorbasin H isolated from Phorbas sp.

Phorbasin H is a diterpene acid of a bisabolane-related skeletal class isolated from the marine sponge Phorbas sp. In this study, we examined whether phorbasin H acted as a yeast-to-hypha transition inhibitor of Candida albicans. Growth experiments suggest that this compound does not inhibit yeast cell growth but inhibits filamentous growth in C. albicans. Northern blot analysis of signaling pathway components indicated that phorbasin H inhibited the expression of mRNAs related to cAMP-Efg1 pathway. The exogenous addition of db-cAMP to C. albicans cells had no influence on the frequency of hyphal formation. The expression of hypha-specific HWP1 and ALS3 mRNAs, both of which are positively regulated by the important regulator of cell wall dynamics Efg1, was significantly inhibited by the addition of phorbasin H. This compound also reduced the ability of C. albicans cells to adhere in a dose-dependent manner. Our findings suggest that phorbasin H impacts the activity of the cAMP-Efg1 pathway, thus leading to an alteration of C. albicans morphology.

Phorbasones A and B, Sesterterpenoids Isolated from the Marine Sponge Phorbas sp. and Induction of Osteoblast Differentiation

Two new sesterterpenoids, phorbasones A (1) and B (2), were isolated from the Korean marine sponge Phorbas sp. Their complete structures were elucidated by spectral data and chemical reactions. Phorbasone A exhibited a positive effect on the calcium deposition activity in C3H10T1/2 cells. The biogenic origin of the core structure is believed to be through a novel rearrangement from the ansellone carbon structure.

Ansellone A, a Sesterterpenoid Isolated from the Nudibranch Cadlina luteromarginata and the Sponge Phorbas sp., Activates the cAMP Signaling Pathway

Ansellone A (1) has been isolated from the dorid nudibranch Cadlina luteomarginata and the sponge Phorbas sp. It has the new "ansellane" sesterterpenoid carbon skeleton, and it activates the cAMP signaling pathway.

ChemInform Abstract: Phorbaketals A, B, and C, Sesterterpenoids with a Spiroketal of Hydrobenzopyran Moiety Isolated from the Marine Sponge Phorbas sp.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Phorbaketals A, B, and C, Sesterterpenoids with a Spiroketal of Hydrobenzopyran Moiety Isolated from the Marine Sponge Phorbas sp.

Three new sesterterpenoids, phorbaketals A (1), B (2), and C (3) which have a spiroketal of the hydrobenzopyran moiety, were isolated from the Korean marine sponge Phorbas sp. Their complete structures were elucidated by spectral and chemical methods. They exhibited moderate cytotoxicity against human colorectal, hepatoma, and lung cancer cell lines. Furthermore, the cultivation of the bacterial fraction from the sponge afforded compound 1.

ChemInform Abstract: Structure Elucidation at the Nanomole Scale. Part 2. Hemi‐phorboxazole A from Phorbas sp.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Phorbasins G–K: new cytotoxic diterpenes from a southern Australian marine sponge, Phorbas sp.

Fractionation of a cytotoxic extract obtained from a southern Australian marine sponge, Phorbas sp., yielded the known diterpenes phorbasins B-F () together with five new members of the phorbasin family, phorbasins G-K (). Structures were assigned to the new phorbasins based on detailed spectroscopic analysis. A preliminary structure activity relationship (SAR) evaluation based on the co-metabolites phorbasins B-K () revealed aspects of the phorbasin pharmacophore.

Total Synthesis of (+)‐Phorboxazole A, a Potent Cytostatic Agent from the Sponge Phorbas sp.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Gagunins, Highly Oxygenated Diterpenoids from the Sponge Phorbas sp.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Total synthesis of (+)-phorboxazole A, a potent cytostatic agent from the sponge Phorbas sp.

A convergent total synthesis of phorboxazole A (1a), from the C(3-19), C(20-27) and C(33-46) fragments 5, 4 and 91, respectively, concentrating on stereocontrolled formation of the bonds at C(2-3), C(19-20) and C(27-28), is described. Although a coupling reaction between a macrolide ketone and the side chain substituted sulfone, at C(27-28) was not successful, a Wadsworth-Emmons olefination involving the oxane methyl ketone 4 and an oxazole produced the oxane 90 which was next coupled to 91 leading to the C(20-46) unit 100. A further coupling of 100 to 71c at C(19-20) then led to 105, ultimately, and the synthesis was completed by a macrocyclisation reaction from 105, at the C(2-3) alkene bond, followed by deprotection of 106.

Gagunins, highly oxygenated diterpenoids from the sponge Phorbas sp.

Gagunins A–G, seven new diterpenoids were isolated from the sponge Phorbas sp. collected from Gagu-Do, Korea. The carbon skeleton of these highly oxygenated metabolites was determined to be an unusual 10,13-bis- epi-homoverrucosane on the basis of combined chemical and spectral methods. Stereochemical assignments of these diterpenoids were accomplished by extensive ROESY and 1D NOESY experiments. The novel compounds exhibited significant cytotoxicity with values ranging from 0.03 to 51 μg/mL, toward a human leukemia cell-line (K-562).