Inhibitory effects of sesquiterpene lactones from the Indonesian marine sponge Lamellodysidea cf. herbacea on bone morphogenetic protein-induced osteoblastic differentiation.

A new unique sesquiterpene lactone, bicyclolamellolactone A (1), was isolated together with two known monocyclofarnesol-type sesquiterpenes, lamellolactones A (2) and B (3), from the Indonesian marine sponge Lamellodysidea sp. (cf. L. herbacea). The planar structure of 1 was assigned based on its spectroscopic data (1D and 2D NMR, HRESIMS, UV, and IR spectra). The relative and absolute configuration of 1 was determined by comparison of its calculated and experimental electronic circular dichroism spectra in combination with NOESY correlations. Compounds 1-3 inhibited bone morphogenic protein (BMP)-induced alkaline phosphatase activity in mutant BMP receptor-carrying C2C12 cells with IC50 values of 51, 4.6, and 20 µM, respectively.

Screening for Small Molecule Inhibitors of BMP-Induced Osteoblastic Differentiation from Indonesian Marine Invertebrates.

Fibrodysplasia ossificans progressiva (FOP) is a rare congenital disorder with heterotopic ossification (HO) in soft tissues. The abnormal activation of bone morphogenetic protein (BMP) signaling by a mutant activin receptor-like kinase-2 (ALK2) leads to the development of HO in FOP patients, and, thus, BMP signaling inhibitors are promising therapeutic applications for FOP. In the present study, we screened extracts of 188 Indonesian marine invertebrates for small molecular inhibitors of BMP-induced alkaline phosphatase (ALP) activity, a marker of osteoblastic differentiation in a C2C12 cell line stably expressing ALK2(R206H) (C2C12(R206H) cells), and identified five marine sponges with potent ALP inhibitory activities. The activity-guided purification of an EtOH extract of marine sponge Dysidea sp. (No. 256) resulted in the isolation of dysidenin (1), herbasterol (2), and stellettasterol (3) as active components. Compounds 1-3 inhibited ALP activity in C2C12(R206H) cells with IC50 values of 2.3, 4.3, and 4.2 µM, respectively, without any cytotoxicity, even at 18.4-21.4 µM. The direct effects of BMP signaling examined using the Id1WT4F-luciferase reporter assay showed that compounds 1-3 did not decrease the reporter activity, suggesting that they inhibit the downstream of the Smad transcriptional step in BMP signaling.

Epipolythiodiketopiperazine and trichothecene derivatives from the NaI-containing fermentation of marine-derived Trichoderma cf. brevicompactum.

The marine-derived fungus Trichoderma sp. TPU199 (cf. Trichoderma brevicompactum) produces pretrichodermamide A (1) and gliovirin (2), which possess a rare type of epipolythiodiketopiperazine (ETP) structure with a disulfide bridge between the α- and ß-positions of two amino acid residues. We previously reported that this strain gave the halogenated ETPs, DC1149B (4), DC1149R (6), and iododithiobrevamide (7), when fermented with sodium halides (NaCl, NaBr, and NaI). Further analyses of the metabolites obtained under NaI-containing culture conditions resulted in the isolation of two new ETP derivatives (11 and 12) and three new trichothecene sesquiterpenes (13-15). The structures of 11 and 12, including their absolute configurations, were elucidated based on spectroscopic data for 11 and 12 and comparisons with those for 1 and related compounds, revealing that 11 was an epimer of 1 at the C-5 position and 12 was a trithio-derivative of 11. The structures of 13-15 were established by analyzing their 1D and 2D NMR data. The absolute configurations of 13-15 were assigned by comparing their experimental electronic circular dichroism (ECD) spectra with the calculated ECD spectrum of 13.

Production of an α-pyrone metabolite and microbial transformation of isoflavones by an Indonesian Streptomyces sp.

A benzyl-α-pyrone metabolite, streptpyrone A (1), was obtained together with three known isoflavonoids, daidzein-7-O-α-l-rhamnoside (2), genistein-7-O-α-l-rhamnoside (3), and daidzein (4), from the culture broth of an Indonesian actinomycete Streptomyces sp. TPU1401A. The structure of 1, elucidated based on its spectroscopic data, has been reported as a synthetic compound. However, this is the first report of the isolation of 1 as a metabolite of microbial origin. Strain TPU1401A exhibited the ability to transform the isoflavone aglycones 4 and genistein (5) into the 7-O-glycosides 2 and 3, respectively. Compounds 2 and 3 promoted the growth of strain TPU1401A more effectively than compounds 4 and 5. These results suggest that strain TPU1401A utilizes isoflavone glycosides to promote growth by transforming isoflavones through microbial glycosidation.

Absolute Structures of Wedelolide Derivatives and Structure-Activity Relationships of Protein Tyrosine Phosphatase 1B Inhibitory ent-Kaurene Diterpenes from Aerial Parts of Wedelia spp. Collected in Indonesia and Japan.

Two sesquiterpene lactones with the (9R)-eudesman-9,12-olide framework, wedelolides I and J, have been isolated together with five eudesmanolide sesquiterpenes and twelve ent-kaurene diterpenes from the aerial parts of Indonesian Wedelia prostrata. The absolute configurations of wedelolides I and J, proposed in the previous communication, were proven by comparing their experimental Electronic Circular Dichroism (ECD) spectra with the calculated ECD spectrum of wedelolide I. The phytochemical study on the aerial parts of Okinawan Wedelia chinensis led to the isolation of three other eudesmanolide sesquiterpenes in addition to the three sesquiterpenes and eleven diterpenes isolated from the Indonesian W. prostrata as above. However, the wedelolide derivatives found in the Indonesian plant were not detected. Among these compounds, most of the diterpenes inhibited protein tyrosine phosphatase (PTP) 1B activity, and a structure-activity relationship study revealed that the cinnamoyl group enhanced inhibitory activity. Therefore, two ent-kaurene derivatives with and without a cinnamoyl group were examined for the ability to accumulate phosphorylated-Akt (p-Akt) because PTP1B dephosphorylates signal transduction from the insulin receptor such as phosphorylated Akt, a key downstream effector. However, neither compound enhanced insulin-stimulated p-Akt levels in two human hepatoma cell lines (Huh-7 and HepG2) at non-cytotoxic doses.

Callyspongiamides A and B, sterol O-acyltransferase inhibitors, from the Indonesian marine sponge Callyspongia sp.

Callyspongiamides A (1) and B (2), two new sterol O-acyltransferase (SOAT) inhibitors, were isolated from the Indonesian marine sponge Callyspongia sp. together with a known congener, dysamide A (3). The structures of 1 and 2 were elucidated to be polychlorine-containing modified dipeptides based on their spectroscopic data. Compounds 1-3 inhibited both of the SOAT isozymes, SOAT1 and SOAT2, in cell-based and enzyme-based assays.

Cladosporamide A, a new protein tyrosine phosphatase 1B inhibitor, produced by an Indonesian marine sponge-derived Cladosporium sp.

Cladosporamide A (1), a new protein tyrosine phosphatase (PTP) 1B inhibitor, was isolated together with a known prenylated flavanone derivative (2) from the culture broth of an Indonesian marine sponge-derived Cladosporium sp. TPU1507 by solvent extraction, ODS column chromatography, and preparative HPLC (ODS). The structure of 1 was elucidated based on 1D and 2D NMR data. Compound 1 modestly inhibited PTP1B and T-cell PTP (TCPTP) activities with IC50 values of 48 and 54 µM, respectively. The inhibitory activity of 2 against PTP1B (IC50 = 11 µM) was approximately 2-fold stronger than that against TCPTP (IC50 = 27 µM).

Oleanane triterpenes with protein tyrosine phosphatase 1B inhibitory activity from aerial parts of Lantana camara collected in Indonesia and Japan.

During the search for new protein tyrosine phosphatase (PTP) 1B inhibitors, EtOH extracts from the aerial parts of Lantana camara L. (lantana) collected at Manado (Indonesia) and two subtropical islands in Japan (Ishigaki and Iriomote Islands, Okinawa) exhibited potent inhibitory activities against PTP1B in an enzyme assay. Four previously undescribed oleanane triterpenes were isolated together with known triterpenes and flavones from the Indonesian lantana. The EtOH extracts of lantana collected in Ishigaki and Iriomote Islands exhibited different phytochemical profiles from each other and the Indonesian lantana. Triterpenes with a 24-OH group were isolated from the Indonesian lantana only. Five known triterpene compounds were detected in the Ishigaki lantana, and two oleanane triterpenes with an ether linkage between 3ß and 25 were the main components together with five known triterpenes as minor components in the Iriomote lantana. The structures of previously undescribed compounds were assigned on the basis of their spectroscopic data. Among the compounds obtained in this study, oleanolic acid exhibited the most potent activity against PTP1B, and is used as a positive control in studies on PTP1B.

Anti-mycobacterial alkaloids, cyclic 3-alkyl pyridinium dimers, from the Indonesian marine sponge Haliclona sp.

Three new dimeric 3-alkyl pyridinium alkaloids, named haliclocyclamines A-C (1-3), were isolated together with five known congeners, cyclostellettamines A (4), B (5), C (6), E (7), and F (8), from the Indonesian marine sponge Haliclona sp. The structures of 1-3 were assigned based on their spectroscopic data (1D and 2D NMR, HRFABMS, ESIMS/MS, UV, and IR). Compounds 1-8 exhibited antimicrobial activities against Mycobacterium smegmatis with inhibition zones of 17, 10, 13, 14, 8, 8, 12, and 12mm, respectively, at 10µg/disc. Compounds 3 and 8 also modestly inhibited the activity of vaccinia H-1-related phosphatase (VHR), a dual-specificity phosphatase, at 17-18µM.

A new biphenyl ether derivative produced by Indonesian ascidian-derived Penicillium albobiverticillium.

A new biphenyl ether derivative, 2-hydroxy-6-(2'-hydroxy-3'-hydroxymethyl-5-methylphenoxy)-benzoic acid (1), was isolated together with the known benzophenone derivative, monodictyphenone (2), from a culture broth of Indonesian ascidian-derived Penicillium albobiverticillium TPU1432 by solvent extraction, ODS column chromatography, and preparative HPLC (ODS). The structure of 1 was elucidated based on NMR experiments. Compound 2 exhibited moderate inhibitory activities against protein tyrosine phosphatase (PTP) 1B, T cell PTP (TCPTP), and CD45 tyrosine phosphatase (CD45), whereas compound 1 modestly inhibited CD45 activity.

An anti-mycobacterial bisfunctionalized sphingolipid and new bromopyrrole alkaloid from the Indonesian marine sponge Agelas sp.

In the course of our studies on anti-mycobacterial substances from marine organisms, the known dimeric sphingolipid, leucettamol A (1), was isolated as an active component, together with the new bromopyrrole alkaloid, 5-bromophakelline (2), and twelve known congeners from the Indonesian marine sponge Agelas sp. The structure of 2 was elucidated based on its spectroscopic data. Compound 1 and its bis TFA salt showed inhibition zones of 12 and 7 mm against Mycobacterium smegmatis at 50 µg/disk, respectively, while the N,N'-diacetyl derivative (1a) was not active at 50 µg/disk. Therefore, free amino groups are important for anti-mycobacterial activity. This is the first study to show the anti-mycobacterial activity of a bisfunctionalized sphingolipid. Compound 13 exhibited weak PTP1B inhibitory activity (29% inhibition at 35 µM).

Furanoterpenes, new types of protein tyrosine phosphatase 1B inhibitors, from two Indonesian marine sponges, Ircinia and Spongia spp.

Protein tyrosine phosphatase (PTP) 1B negatively regulates the insulin and leptin signaling pathways, and, thus, the clinical application of PTP1B inhibitors to the prevention and treatment of type 2 diabetes and obesity is expected. During our studies on PTP1B inhibitors, two furanosesterterpenes and a C21 furanoterpene were obtained as new types of PTP1B inhibitors from two Indonesian marine sponges. (7E, 12E, 20Z, 18S)-Variabilin (1) and (12E, 20Z, 18S)-8-hydroxyvariabilin (2) from Ircinia sp. and furospongin-1 (3) from Spongia sp. inhibited PTP1B activity with IC50 values of 1.5, 7.1, and 9.9µM, respectively. The inhibitory activity of compound 1 against T-cell PTP (TCPTP) was approximately 2-fold that against PTP1B, whereas the vaccinia H-1-related phosphatase (VHR) inhibitory effects of 1 were 4-fold weaker than that of its PTP1B inhibitory activity. Compounds 1-3 at 50µM did not show cytotoxicity against two human cancer cell lines, hepatoma Huh-7 and bladder carcinoma EJ-1. Compound 1 did not enhance the phosphorylation level of Akt, a key downstream effector of the cascade, in Huh-7 cells.

Lissoclibadin 1, a Polysulfur Aromatic Alkaloid from the Indonesian Ascidian Lissoclinum cf. badium, Induces Caspase-Dependent Apoptosis in Human Colon Cancer Cells and Suppresses Tumor Growth in Nude Mice.

Lissoclibadins, polysulfur aromatic alkaloids, were isolated from the Indonesian ascidian Lissoclinum cf. badium. Lissoclibadins 1 (1), 3 (2), 4 (3), 7 (4), 8 (5), and 14 (6) inhibited the growth of four human solid cancer cell lines: HCT-15 (colon adenocarcinoma), HeLa-S3 (cervix adenocarcinoma), MCF-7 (breast adenocarcinoma), and NCI-H28 (mesothelioma). Lissoclibadin 1 (1) exerted the most potent cytotoxic effects in vitro and mainly promoted apoptosis through an intrinsic pathway with the activation of a caspase-dependent pathway in HCT-15 cells. In vivo studies demonstrated that 1 suppressed tumor growth in nude mice carrying HCT-15 cells without significant secondary adverse effects. In conclusion, the results obtained in the present study demonstrate that 1 has potential as a chemotherapeutic candidate for preclinical investigations.

A tetramic acid derivative with protein tyrosine phosphatase 1B inhibitory activity and a new nortriterpene glycoside from the Indonesian marine sponge Petrosia sp.

During the search for protein tyrosine phosphatase 1B (PTP1B) inhibitors from marine organisms, the known tetramic acid derivative, melophlin C (1), was isolated as an active component together with the new nortriterpenoid saponin, sarasinoside S (2), and three homologues: sarasinosides A1 (3), I1 (4), and J (5), from the Indonesian marine sponge Petrosia sp. The structure of 2 was elucidated on the basis of its spectroscopic data. Compound 1 inhibited PTP1B activity with an IC50 value of 14.6µM, while compounds 2-5 were not active at 15.2-16.0µM. This is the first study to report the inhibitory effects of a tetramic acid derivative on PTP1B activity.

Induced Production of Halogenated Epidithiodiketopiperazines by a Marine-Derived Trichoderma cf. brevicompactum with Sodium Halides.

Marine-derived Trichoderma sp. TPU199 (cf. T. brevicompactum) produced gliovirin (1), pretrichodermamide A (2), and trichodermamide A (3) in a freshwater medium. Compounds 1 and 2 are rare epidithiodiketopiperazines possessing an unusual disulfide linkage. In the seawater medium, the strain biosynthesized the 5-chloro-5-deoxy derivatives (4 and 5) of 3 and 2. The production of 5 was proportional to the concentration of seawater (NaCl). Therefore, 5-bromo-5-deoxy (6) and 5-deoxy-5-iodo (7) derivatives were biosynthesized in the freshwater media supplemented with NaBr and NaI, respectively. The structure of a new iodo derivative (7) was elucidated on the basis of its spectroscopic data.

Verruculides A and B, two new protein tyrosine phosphatase 1B inhibitors from an Indonesian ascidian-derived Penicillium verruculosum.

Two new merosesquiterpenes, verruculides A (1) and B (2), were isolated from a culture broth of the Indonesian ascidian-derived Penicillium verruculosum TPU1311, together with three known congeners, chrodrimanins A (3), B (4), and H (5). The structures of 1 and 2 were assigned on the basis of their spectroscopic data (1D and 2D NMR, HRMS, UV, CD, and IR). Compound 2 had a linear sesquiterpene moiety and was considered to be the derivative of the biosynthetic precursor for 1 and 3-5. Compounds 1, 3, and 5 inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 8.4, 8.5, and 14.9 µM, respectively. Compound 2 showed 40% inhibition at 23.1 µM, while 4 was not active at 20.7 µM.

Variabines A and B: new ß-carboline alkaloids from the marine sponge Luffariella variabilis.

Two new ß-carboline alkaloids, variabines A (1) and B (2), were isolated from the Indonesian marine sponge Luffariella variabilis. Their structures were elucidated from spectral data, and 1 was found to be a sulfonated derivative of 2. Although numerous ß-carboline alkaloids have been isolated from natural sources to date, 1 is the first ß-carboline derivative containing a sulfate group. Compound 2 inhibited chymotrypsin-like activity of the proteasome and Ubc13 (E2)-Uev1A interaction with IC50 values of 4 and 5 µg/mL, respectively, whereas 1 had little effect on the activity or interaction.

Manzamine A, a marine-derived alkaloid, inhibits accumulation of cholesterol ester in macrophages and suppresses hyperlipidemia and atherosclerosis in vivo.

The formation of foam cells in macrophages plays an essential role in the progression of early atherosclerotic lesions and therefore its prevention is considered to be a promising target for the treatment of atherosclerosis. We found that an extract of the marine sponge Acanthostrongylophora ingens inhibited the foam cell formation induced by acetylated low-density lipoprotein (AcLDL) in human monocyte-derived macrophages, as measured based on the accumulation of cholesterol ester (CE). Bioassay-guided purification of inhibitors from the extract afforded manzamines. Manzamine A was the most potent inhibitor of foam cell formation, and also suppressed CE formation in Chinese hamster ovary cells overexpressing acyl-CoA:cholesterol acyl-transferase (ACAT)-1 or ACAT-2. In addition, manzamine A inhibited ACAT activity. Next, we orally administered manzamine A to apolipoprotein E (apoE)-deficient mice for 80 days, and found that total cholesterol, free cholesterol, LDL-cholesterol, and triglyceride levels in serum were significantly reduced and the area of atherosclerotic lesions in the aortic sinus was also substantially diminished. These findings clearly suggest that manzamine A suppresses hyperlipidemia and atherosclerosis in apoE-deficient mice by inhibiting ACAT and is therefore a promising lead compound in the prevention or treatment of atherosclerosis. Although manzamine A has been reported to show several biological activities, this is the first report of a suppressive effect of manzamine A on atherosclerosis in vivo.

Spongiacidin C, a pyrrole alkaloid from the marine sponge Stylissa massa, functions as a USP7 inhibitor.

USP7, a deubiquitylating enzyme hydrolyzing the isopeptide bond at the C-terminus of ubiquitin, is an emerging cancer target. We isolated spongiacidin C from the marine sponge Stylissa massa as the first USP7 inhibitor from a natural source. This compound inhibited USP7 most strongly with an IC50 of 3.8 µM among several USP family members tested.