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.

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.

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.

A New Pyranonaphtoquinone Derivative, 4-Oxo-rhinacanthin A, from Roots of Indonesian Rhinacanthus nasutus.

A new pyranonaphthoquinone derivative, named 4-oxo-rhinacanthin A (1), was isolated from the roots of the Indonesian Rhinacanthus nasutus together with two known congeners, rhinacanthin A (2) and 3,4-dihydro-3,3-dimethyl-2H-naphtho[2,3-b]pyran-5,10-dione (3). The structure of 1 was elucidated based on its spectroscopic data. The absolute configuration of 1 was assigned by comparing its experimental Electronic Circular Dichroism (ECD) spectrum with the calculated ECD spectrum. Compounds 2 and 3 inhibited the growth of Staphylococcus aureus with inhibition zones of 16 and 20 mm at 25 µg/disc, respectively. Compound 3 also exhibited inhibitory activity against Mycobacterium smegmatis (20 mm at 25 µg/disc).

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 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.

Protein tyrosine phosphatase 1B inhibitory properties of seco-cucurbitane triterpenes obtained from fruiting bodies of Russula lepida.

The known seco-cucurbitane triterpene, (24E)-3,4-seco-cucurbita-4,24-diene-3,26,29-trioic acid (1), has been isolated as a potent protein tyrosine phosphatase (PTP) 1B inhibitor together with a new analogue, (24E)-3,4-seco-cucurbita-4,24-diene-3-hydroxy-26,29-dioic acid (2), from the fruiting bodies of Russula lepida. Further evaluation of their biological properties against PTPs revealed that compound 1 inhibited T-cell PTP activity similarly to PTP1B and exhibited moderate selectivity against PTP1B over vaccinia H-1-related phosphatase. Moreover, the in vitro growth inhibitory effects of 1 and 2 against three human cancer cell lines were examined in order to evaluate cell-based efficacy. However, neither 1 nor 2 enhanced insulin-stimulated p-Akt levels at non-cytotoxic concentrations.

Structures and biological activities of triterpenes and sesquiterpenes obtained from Russula lepida.

A seco-cucurbitane triterpene and two aristolane sesquiterpenes, named (24E)-3,4-seco-cucurbita-4,24-diene-3-hydroxy-26,29-dioic acid, (+)-1,2-didehydro-9-hydroxy-aristlone, and (+)-12-hydroxy-aristlone, were isolated from fruiting bodies of the medicinal mushroom Russula lepida, together with (24E)-3,4-seco-cucurbita-4,24-diene-3,26,29-trioic acid and (+)-aristlone. The structures of the first three compounds, including their absolute configurations, were assigned on the basis of their NMR and ECD spectra. Two seco-cucurbitane triterpenes, (24E)-3,4-seco-cucurbita-4,24-diene-3-hydroxy-26,29-dioic acid and (24E)-3,4-seco-cucurbita-4,24-diene-3,26,29-trioic acid, inhibited the activity of protein tyrosine phosphatase 1B (PTP1B), with IC50 values of 20.3 and 0.4µM, respectively. All isolated compounds did not show cytotoxicity against human cancer cell lines, Huh-7 (hepatoma) and EJ-1 (bladder), at 50µM.

Siladenoserinols A-L: new sulfonated serinol derivatives from a tunicate as inhibitors of p53-Hdm2 interaction.

Siladenoserinols A-L were isolated from a tunicate as inhibitors of p53-Hdm2 interaction, a promising target for cancer chemotherapy. Their structures including the absolute configurations were elucidated to be new sulfonated serinol derivatives, each of which contains a 6,8-dioxabicyclo[3.2.1]octane unit and either glycerophosphocholine or glycerophosphoethanolamine moiety. They inhibited p53-Hdm2 interaction with IC(50) values of 2.0-55 µM. Among them, siladenoserinol A and B exhibited the strongest inhibition with an IC(50) value of 2.0 µM.

Five new diterpenoids from an Okinawan soft coral, Cespitularia sp.

Five new diterpenoids 1-5 were isolated from an Okinawan soft coral, Cespitularia sp., together with the known diterpenoid, alcyonolide (6). New diterpenoid structures were elucidated by spectroscopic methods and by comparison of their NMR data with those of related compounds. Alcyonolide (6) was cytotoxic against HCT 116 cells (IC50 5.85 µM), while these new diterpenoids 1-5 were much less active (IC50 28.2-91.4 µM).

Isolation of C11 compounds and a cyclopropane fatty acid from an Okinawan ascidian, Diplosoma sp.

Pentylphenols 1 and 2, cyclopropane fatty acid 3, and cyclopentenones 4 and 5, were isolated from an ascidian, Diplosoma sp. The structures of 1-5 were determined by spectroscopic analysis and/or synthesis. Compound 1 inhibited the division of fertilized sea urchin eggs and compound 4 showed mild cytotoxity against HCT116 cells (human colorectal cancer cell).