A polybromodiphenyl ether from an Indonesian marine sponge Lamellodysidea herbacea and its chemical derivatives inhibit protein tyrosine phosphatase 1B, an important target for diabetes treatment

The ethanol extract of an Indonesian marine sponge Lamellodysideaherbacea inhibited the activity of protein tyrosine phosphatase 1B (PTP1B), an important target enzyme for the treatment of type II diabetes. Bioassay-guided isolation yielded a known polybromodiphenyl ether (1) as a sole bioactive component. The structure of 1 was confirmed by spectroscopic data for 1 and its methyl ether derivative (2). Compound 1 markedly inhibited the PTP1B activity (IC₅₀ = 0.85 μM) and showed a moderate cytotoxicity against two human cancer cell lines, HCT-15 (colon) and Jurkat (T-cell lymphoma) cells. On the other hand, compound 2 maintained potent inhibitory activity against PTP1B (IC₅₀ = 1.7 μM) but did not show apparent cytotoxicity at 18 μM against these cancer cells. Four ester derivatives [acetyl (3), butyryl (4), hexanoyl (5), and benzoyl (6)] were prepared from 1 and their activities evaluated against PTP1B and two cancer cell lines to investigate the structure–activity relationships. Although compounds 3–6 exhibited potent inhibitory effects against PTP1B activity, cytotoxicity against HCT-15 and Jurkat cells was observed as a similar efficacy to that of 1. From these results, compound 2 was found to be the best inhibitor of PTP1B with no apparent cytotoxicity. Therefore, 2 may be a lead compound for making a new type of PTP1B inhibitor. Moreover, compound 2 did not inhibit the cell growth of Huh-7 cells (hepatoma). Hepatocytes are one of the locations of PTP1B, and Huh-7 cells are used to study the mechanism of action of compound 2.

Polymorphism in Nucleotide Sequence of Mitochondrial Intergenic Region in Scleractinian Coral (Galaxea fascicularis)

A region of 826 bp that is unlikely to code for a protein, ribosomal RNA, or transfer RNA was identified between the cytochrome b and NADH-ubiquinone oxidoreductase chain 2 loci in the mitochondrial DNA of the scleractinian reef coral Galaxea fascicularis. Nucleotide sequences were determined in a part (625 bp) of this intergenic region in 95 individuals collected at 9 sites in the Ryukyu Archipelago in southwestern Japan. A total of 8 haplotypes were found, and a deletion of 290 bp was found in 3 of them. Significant differences were found in frequencies of the haplotypes at 3 sampling sites. The presence or absence of the deletion was highly correlated with the hard or soft morphotype. The deletion was found in the majority of hard-type colonies, but in a small fraction of soft-type individuals.

Papuamine and haliclonadiamine, obtained from an Indonesian sponge Haliclona sp., inhibited cell proliferation of human cancer cell lines

The extract of an Indonesian marine sponge Haliclona sp. showed potent cytotoxicity against human solid cancer cell lines, MCF-7 (breast), LNCap (prostate), Caco-2 (colon) and HCT-15 (colon) cells. Study on nuclear morphological changes and flow cytometric analysis suggested that the component(s) in the extract would induce an apoptosis to these cancer cells. Bioassay-guided isolation yielded two pentacyclic alkaloids, papuamine (1) and haliclonadiamine (2), which inhibited cell proliferation of six human cancer cell lines with IC50 values of 0.93-1.50 and 1.00-4.44 µM, respectively. Compounds 1 and 2 accumulated lymphoma U937 cells at sub-G1 phase and induced a condensation of chromatin and fragmentation of nucleus.

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).

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 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.

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 3β 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.

(25S)-cholesten-26-oic acid derivatives from an Indonesian soft coral Minabea sp

(25S)-3-Oxocholesta-1,4-dien-26-oic acid (1) and a new (25S)-18-acetoxy-3-oxocholesta-1,4-dien-26-oic acid (2) were isolated from a soft coral Minabea sp. (cf. aldersladei) collected in North Sulawesi, Indonesia, together with two known cholic-acid-type compounds, 3-oxochol-1,4-dien-24-oic acid (3) and 3-oxochol-4-en-24-oic acid (4). The structures of these compounds were determined on the basis of their spectroscopic data. The absolute stereochemistry at C-25 of 2 was determined by comparative (1)H NMR study using chiral anisotropic reagents [(S)- and (R)-phenylglycine methyl esters]. This is the first to report compound 1 as a natural product.

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.

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.

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.

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.