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Jun-ya Ueda,1,2 Sirivan Athikomkulchai,3 Ryuta Miyatake,4 Ikuo Saiki,2 Hiroyasu Esumi,5,6 Suresh Awale1,21Frontier Research Core for Life Sciences, 2Institute of Natural Medicine, University of Toyama, Toyama, Japan; 3Faculty of Pharmacy, Srinakharinwirot University, Nakhon Nayok, Thailand; 4Graduate School of Science and Engineering, University of Toyama, Toyama, Japan; 5Research Institute for Biomedical Sciences, Tokyo University of Science, 6National Cancer Center Hospital East, Chiba, JapanAbstract: Human pancreatic tumors are known to be highly resistant to nutrient starvation, and this prolongs their survival in the hypovascular (austere) tumor microenvironment. Agents that retard this tolerance to nutrient starvation represent a novel antiausterity strategy in anticancer drug discovery. (+)-Grandifloracin (GF), isolated from Uvaria dac, has shown preferential toxicity to PANC-1 human pancreatic cancer cells under nutrient starvation, with a PC50 value of 14.5 µM. However, the underlying mechanism is not clear. In this study, GF was found to preferentially induce PANC-1 cell death in a nutrient-deprived medium via hyperactivation of autophagy, as evidenced by a dramatic upregulation of microtubule-associated protein 1 light chain 3. No change was observed in expression of the caspase-3 and Bcl-2 apoptosis marker proteins. GF was also found to strongly inhibit the activation of Akt, a key regulator of cancer cell survival and proliferation. Because pancreatic tumors are highly resistant to current therapies that induce apoptosis, the alternative cell death mechanism exhibited by GF provides a novel therapeutic insight into antiausterity drug candidates.Keywords: (+)-grandifloracin, antiausterity strategy, PANC-1, nutrient starvation

Human pancreatic cancer is resistant to almost all conventional chemotherapeutic agents. It is known to proliferate aggressively within hypovascular tumor microenvironment by exhibiting remarkable tolerance to nutrition starvation,  a phenomenon termed as "austerity". Search for the new agents that eliminate the tolerance of cancer cells to nutrition starvation is a promising strategy in anticancer drug discovery. In this study, two new meroterpenoids named callistrilones O and P (1 and 2) together with eight known triterpenes (3-10) were isolated from the active dichloromethane extract of Callistemon citrinus leaves. The structure elucidation of the new compounds was achieved by HRFABMS, 1D, 2D NMR, and ECD quantum calculations. All isolated compounds were tested for their preferential cytotoxicity against PANC-1 human pancreatic cancer cells. Among these, callistrilone O (1) exhibited the most potent preferential cytotoxicity with a PC 50 value of 0.3 nM, the strongest activity with over 2000 times potent than the positive control arctigenin. Callistrilone O (1) induced dramatic alterations in PANC-1 cell morphology leading to cell death under nutrient-deprived conditions. Compound 1 also inhibited PANC-1 cell migration and -PANC-1 colony formation under the nutrient-rich condition., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Human pancreatic cancer cells display remarkable tolerance to nutrition starvation that help them to survive in a hypovascular tumor microenvironment, a phenomenon known as "austerity". The elucidation of agents countering this tolerance is an established antiausterity strategy in anticancer drug discovery. In this study, a Callistemon citrinus leaf extract inhibited the viability of PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived medium (NDM) with a PC 50 value of 7.4 μg/mL. Workup of this extract resulted in the isolation of three new meroterpenoids, callistrilones L-N ( 1 - 3 ), together with 14 known compounds ( 4 - 17 ). The structure elucidation of the new compounds was achieved by HRFABMS and by NMR and ECD spectroscopic analysis. The new compounds showed highly potent preferential cytotoxicity against PANC-1 cells with PC 50 values ranging from 10 to 65 nM in NDM. Of these, callistrilone L ( 1 ) inhibited PANC-1 cell migration and colony formation in a normal nutrient-rich condition. Callistrilone L ( 1 ) also strongly suppressed the migration of PANC-1 cells in real time. Mechanistically, 1 was found to inhibit the Akt/mTOR and autophagy activation pathway. Callistrilone L ( 1 ) and related meroterpenoids are promising leads for anticancer drug development based on the antiausterity strategy used in this work.

The chloroform extract of the Japanese cypress Chamaecyparis obtusa was found to kill PANC-1 human pancreatic cancer cells preferentially in the nutrient-deprived medium without causing toxicity in the nutrient rich condition. Phytochemical investigation on this extract led to the isolation of a new sesquiterpene (1), together with the six sesquiterpenes (2-7) and a lignan (8). The isolated compounds were tested for their preferential cytotoxicity activity against five different human pancreatic cancer cell lines [PANC-1, MIA PaCa2, CAPAN-1, PSN-1, and KLM-1] by utilizing an antiausterity strategy. Among them, α-cadinol (2) was identified as the most active constituent. α-Cadinol (2) was found to inhibit the activation of Akt/mTOR pathway, and the hyperactivation of autophagy leading to preferential PANC-1 cell death during nutrient-starvation., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

From the chloroform extract of the leaves of Uvaria dac, four new highly-oxygenated cyclohexene derivatives named uvaridacols I-L (1-4) were isolated together with nine previously reported compounds (5-13). Their structures were determined based on the extensive NMR spectroscopic data and circular dichroism spectroscopic analysis. Among the new compounds, uvaridacol L (4) displayed strong preferential cytotoxicity in the nutrient deprived medium against five different tested pancreatic cancer cell lines, PANC-1 (PC 50 , 20.1μM), PSN-1 (PC 50 , 9.7μM), MIA PaCa-2 (PC 50 , 29.1μM), Capan-1 (73.0μM) and KLM-1 (25.9μM)., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Phytochemical investigation of the CH2Cl2 extract of the Vietnamese medicinal plant Caesalpinia sappan Linn resulted in the isolation of a new cassane-type diterpene named tomocin I (1). Its chemical structure was determined by NMR spectroscopic and mass spectrometric analysis.

A series of functionalized coumarins were synthesized and evaluated for their capacity to inhibit the resistance to starvation of pancreatic cancer cells. This form of cytotoxicity, termed 'antiausterity' activity, was evaluated using a preferential cytotoxicity assay that compared cell survival in nutrient poor and nutrient rich conditions. Six of the seventeen compounds showed weak antiausterity activity against PANC-1. Compound 34 was active against PANC-1, MIA PaCa-2, and Capan-1 cancer cell lines. All of the compounds tested were simplified structural analogs of previously reported natural product leads. Six of the compounds, including 34, contain functionalized triazoles as novel potential bioisosteres of the side chain of the natural product angelmarin. Overall, the analogs were found to have low antiausterity activity relative to the corresponding natural products., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Eight structurally diverse cassane diterpenes named tomocins A-H were isolated from the seed kernels of Vietnamese Caesalpinia sappan Linn. Their structures were determined by extensive NMR and CD spectroscopic analysis. Among the isolated compounds, tomocin A, phanginin A, F, and H exhibited mild preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived condition without causing toxicity in normal nutrient-rich conditions., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

An attempt to synthesize aglycone 1 derived from 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside (THSG) via the Wittig reaction and Mizoroki-Heck reaction is described. In the Wittig protocol, 2,3,5,4'-tetramethoxystilbene 2 was obtained. Additionally, a palladium-catalyzed Mizoroki-Heck reaction strategy yielded 2-aryl-2,3-dihydrobenzofuran 13 instead of derivative 12 in good yield.

Human pancreatic cancer cell lines have remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions is a novel antiausterity strategy in anticancer drug discovery. In this study, the methanolic extract of the leaves of Artocarpus altilis showed 100 % preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions at a concentration of 50 µg/mL. Further investigation of this extract led to the isolation of eight new geranylated dihydrochalcones named sakenins A-H (1-8) together with four known compounds (9-12). Among them, sakenins F (6) and H (8) were identified as potent preferentially cytotoxic candidates with PC50 values of 8.0 µM and 11.1 µM, respectively., (Georg Thieme Verlag KG Stuttgart · New York.)

Series of 2-pyridineformamide thiosemicarbazones were synthesized. Their preferential cytotoxicity in nutrient deprived medium (NDM) was evaluated using PANC-1 human pancreatic cancer cells by employing an antiausterity strategy. 2-Pyridineformamide thiosemicarbazones induced apoptosis and exhibited preferential cytotoxic activity toward PANC-1 cells in NDM, with potencies in the submicromolar range. These compounds are potential candidates for the development of therapeutics against pancreatic cancer., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Three new cleistanthane diterpenes named tomocinon (1), tomocinol A (2), and tomocinol B (3), were isolated from the EtOAc extract of the seed of Caesalpinia sappan. Their structures were determined by extensive NMR spectroscopic analysis. The absolute stereochemistry of tomocinon (1) has been established by CD spectroscopic analysis. Cleistanthane diterpenes (1-3) represents the novel class of antiausterity agents having preferential cytotoxicity against PANC-1 human pancreatic cancer cell line under nutrient deprived condition with PC50 value of 34.7 μM, 42.4 μM and 39.4 μM, respectively., (© 2013.)

Chemical investigation of the stems of Uvaria dac yielded four new highly oxygenated cyclohexene derivatives named uvaridacols E-H (1-4). Their structures were established through NMR and circular dichroism spectroscopic analysis. Uvaridacols E (1), F (2), and H (4) displayed weak preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions in a concentration-dependent manner, without causing toxicity in normal nutrient-rich conditions.

Human pancreatic cancer cell lines are known for their inherent tolerance to nutrition starvation, which enables them to survive under a hypovascular (austerity) tumor microenvironment. The search for agents that preferentially retard the survival of cancer cells under low nutrition conditions (antiausterity agent) is a novel approach to anticancer drug discovery. In this study, it was found that a dichloromethane extract of the stem of Uvaria dac preferentially inhibited PANC-1 human pancreatic cancer cells survival under nutrition-deprived conditions at a concentration of 10 μg/mL. Workup of this bioactive extract led to the discovery of (+)-grandifloracin (8) as a potent antiausterity agent as evaluated in a panel of four human pancreatic cancer cell lines, PANC-1 (PC(50), 14.5 μM), PSN-1 (PC(50), 32.6 μM), MIA PaCa-2 (PC(50), 17.5 μM), and KLM-1 (32.7 μM). (+)-Grandifloracin (8) has been isolated from a natural source for the first time. Its absolute stereochemistry was established by single-crystal X-ray crystallography and circular dichroism spectroscopic analysis. In addition to this, seven other new highly oxygenated cyclohexene derivatives, named uvaridacanes A (1) and B (2), uvaridacols A-D (3, 4, 6, 7), and uvaridapoxide A (5), were also isolated and structurally characterized.

To investigate the biological activity of a novel 24-membered macrolide compound, JBIR-19, isolated from the culture broth of the entomopathogenic fungus Metarhizium sp. fE61, morphological changes in yeast cells were examined using the automated image-processing program CalMorph. Principal components analysis was used to elucidate dynamic changes in the phenotypes, revealing two independent effects of JBIR-19 in yeast cells: bud elongation and increased size of the actin region. Using a fitness assay, we identified the genes required for robust growth in the presence of JBIR-19. Among these were CCW12, YLR111W, and DHH1, which are also involved in abnormal bud morphology. Based on these results and others, we predict intracellular targets of JBIR-19 and its functional interactions., (© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is an enzyme that catalyzes hydrolysis of 3'-phosphotyrosyl bonds and is involved in repair of irreversible topoisomerase I (Top1)-DNA covalent complexes. Tdp1 inhibitors are regarded as potential cancer therapeutics in combination with Top1 inhibitors, which are currently used to treat human cancers. While screening for Tdp1 inhibitors, we discovered a novel compound, JBIR-21 (1), from the culture of an anamorphic fungus, RF-13305. The structure of 1 was established by extensive NMR and MS analyses. Compound 1 showed inhibitory activity against Tdp1 (IC(50) value, 18 μM) and cytotoxic activity against cancer cell lines (IC(50) values, 3.5-13 μM). Compound 1 also exhibited antitumor activity in a mouse xenograft model without adverse effects., (© 2012 American Chemical Society and American Society of Pharmacognosy)

Background: We recently reported that the MeOH extract of aerial parts and root of Rhinacanthus nasutus showed diverse biological activity, with most activity being concentrated into the EtOAc layer separated by sequential organic solvent extractions. In the present study, the EtOAc extracts were further separated by silica-gel column chromatography into five fractions (Frs. 1-5), and their cytotoxicity and apoptosis-inducing activity investigated., Materials and Methods: Cytotoxic activity was determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method. The 50% cytotoxic concentration (CC(50)) was determined from the dose-response curve. Tumor specificity (TS) was determined by the ratio of the mean CC(50) for normal cells to the one for tumor cell lines. DNA fragmentation was assayed by agarose gel electrophoresis. Caspase-3/-7 activation was monitored by cleavage of substrates either spectrophotometrically or by western blot analysis., Results: Among five fractions of the EtOAc extract, Fr. 1, eluted with CHCl(3)-MeOH (50:1), showed the highest tumor specificity (TS=3.3) as compared with other fractions eluted at higher concentrations of MeOH in CHCl(3) (TS=1.0-2.8). Fr. 1 did not induce internucleosomal DNA fragmentation or induced only marginal level of caspase-3 activity in either human promyelocytic leukemia HL-60 cells and human oral squamous cell carcinoma (OSCC) cell lines HSC-2., Conclusion: The present study suggests that hydrophobic substances of EtOAc extract show tumor specific cytotoxicity by inducing little or no apoptosis.

Background: We recently reported that the MeOH extract from bulbs of Odontioda Marie Noel 'Velano' exhibited diverse biological activities but most of the activity was concentrated into the EtOAc layer separated by sequential organic solvent extractions. In the present study, the EtOAc layer was subjected to silica-gel column chromatography for further separation into five fractions, and the cytotoxicity and apoptosis-inducing activity of the fractions against human normal oral and tumor cells was further investigated., Materials and Methods: Cytotoxic activity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The 50% cytotoxic concentration (CC(50)) was determined by the dose-response curve. Tumor specificity (TS) was determined by the ratio of the mean CC(50) for normal cells to the one of tumor cell lines. DNA fragmentation was assayed by agarose gel electrophoresis, caspase-3/-7 activation was monitored by cleavage of substrates either spectrophotometrically or by western blot analysis., Results: Among five fractions, the most hydrophobic fraction (Fr. 1) showed the highest cytotoxicity against all cell lines tested, followed by Fr. 2 >Fr. 3 >Fr. 4 >Fr. 5, in order of increasing polarity. Fr. 2 had the highest tumor-specificity, followed by Fr. 3, Fr. 4, Fr. 1 and Fr. 5. Fr. 1 induced caspase-3 activation more potently in promyelocytic leukemia HL-60 cells, than in oral squamous cell carcinoma (OSCC) HSC-2 cells, whereas it did not induce internucleosomal DNA fragmentation in either of these cell lines., Conclusion: The present study suggests that hydrophobic substances in the EtOAc extract of Odontioda Marie Noel 'Velano' exhibit tumor-specific cytotoxicity without inducing apoptosis in the HSC-2 OSCC cell line.

Searching for metabolites from Streptomyces sp. RI051-SDHV6 resulted in the discovery of a novel peptide, JBIR-96 (1). The structure of 1 was established as an N-phenylacetylated pentapeptide involving a cysteic acid and a peptide lactone structure by extensive NMR and MS analyses. In addition, the absolute configuration of 1 was established by Marfey's and modified Mosher's methods.

Background: Several pharmacologically active substances have been isolated from orchid plants, but not from Odontoglossum Harvengtense 'Tutu'. Whether MeOH extract fractions from Odontoglossum Harvengtense 'Tutu' bulb exert biological activity was investigated., Materials and Methods: The MeOH extract was stepwise separated by organic solvents into n-hexane, EtOAc, n-BuOH and H(2)O layer fractions. Cytotoxic activity against human tumor and normal cells was determined by MTT method. Nitric oxide (NO) was determined by Griess method. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity., Result: Among four fractions, the EtOAc fraction showed the highest tumor-specific cytotoxicity, and inhibited NO production by lipopoly-saccharide (LPS)-stimulated mouse macrophage-like cells and receptor activator for nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis to the greatest extent., Conclusion: As compared with Odontioda Marie Noel 'Velano' bulbs, the anti-tumor and anti-inflammatory substances of Odontoglossum Harvengtense 'Tutu' are concentrated more exclusively into the EtOAc fraction.

In the course of our screening program for anticancer agents from natural sources, five new angucyclines, JBIR-90 (1), -116 (2), -91 (3), -92 (4) and -93 (5), were isolated from the fermentation broth of Streptomyces sp. RI33. The structures of 1-5 were elucidated on the basis of 1D and 2D NMR spectroscopy and MS analyses. Compounds 2-4 showed cytotoxic activities against malignant pleural mesothelioma cells at IC(50) values of 20-50 μM., (© 2011 Japan Antibiotics Research Association All rights reserved)

Background: The MeOH extracts from aerial part and roots of Rhinacanthus nasutus were investigated for new biological activities., Materials and Methods: The MeOH extract of the root was stepwise separated by organic solvents into n-hexane, EtOAc, n-BuOH and H(2)O layer fractions. Cytotoxic activity against human tumor and normal cells was determined by the MTT method. Nitric oxide (NO) was determined by the Griess method. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity., Results: The MeOH extract of the root showed much higher tumor-specific cytotoxicity than that of the aerial part. The EtOAc fraction of the root showed the highest tumor-specific cytotoxicity, followed by the n-BuOH, n-hexane and H(2)O fractions. None of the four fractions protected the cells from the cytotoxicity of UV irradiation. The n-BuOH fraction not only stimulated NO production by mouse macrophage-like RAW264.7 cells, but also inhibited the lipopolysaccharide (LPS)-stimulated NO production. The EtOAc fraction inhibited the receptor activator for nuclear factor-κB ligand (RANKL)-stimulated osteoclastogenesis of the RAW264.7 cells most potently, followed by the n-hexane, n-BuOH and H(2)O fractions. The n-BuOH fraction slightly, but significantly stimulated osteoclastogenesis., Conclusion: Antitumor and macrophage/osteoclast-modulating substances are enriched in EtOAc and n-BuOH fractions of MeOH extract of R. nasutus roots.

Background: Several pharmacologically active substances have been isolated from orchid plants other than Odontioda Marie Noel 'Velano'. Whether or not MeOH extract fractions from O. Marie Noel 'Velano' bulbs exert various biological activities was investigated., Materials and Methods: The MeOH extract was stepwise separated by organic solvents into n-hexane, EtOAc, n-BuOH and H(2)O layer fractions. Cytotoxic activity against human tumor and normal cells was determined by the MTT method. Nitric oxide (NO) was determined by the Griess method. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity., Result: The EtOAc fraction showed the highest tumor-specific cytotoxicity, followed by the n-hexane and other fractions. The EtOAc and n-BuOH fractions protected the cells from the cytotoxicity induced by UV irradiation. The EtOAc and n-hexane fractions inhibited NO production by lipopolysaccharide (LPS)-stimulated mouse macrophage-like cells. The EtOAc fraction most strongly inhibited the receptor activator for nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis, followed by the n-BuOH, n-hexane and H(2)O fractions., Conclusion: Most of the biological activities tested were concentrated in the EtOAc fraction, and separation from cytotoxic substances is needed to identify the active principle(s).

Two new aminocaprophenone alkaloids, ficuseptamines A (1) and B (2), and a new pyrrolidine alkaloid, ficuseptamine C (3), together with 12 known alkaloids and a known acetophenone derivative were isolated from a methanolic extract of the leaves of Ficus septica. The structures of 1-3 were determined on the basis of their spectroscopic data. The compounds obtained were evaluated for cytotoxicity against two cancer cell lines.

Efficient synthesis of the deoxysugar part of versipelostatin (VST) was achieved by direct and stereoselective glycosylation of the reduced VST aglycon. Activation of 2-deoxyglycosyl imidate with IBr under basic conditions enables alpha-selective glycosylation of beta-2-deoxylglycosides without anomerization. Comparison of the synthetic and natural VST products using NMR indicates that versipelostatin has a beta-D-digitoxose-(1,4)-alpha-L-oleandrose-(1,4)-beta-D-digitoxose trisaccharide. In addition, results of a biological assay indicate that the deoxyoligosaccharide unit of the synthetic glycoside was important for biological activity of the compound.

Sequence analysis of ketosynthase domain amplicons from Streptomyces bicolor NBRC 12746(T) revealed the presence of previously unreported type I polyketide synthases (PKS-I) genes. The clustering of these genes with the reference PKS-1 sequences suggested the possibility to produce a polyene compound similar to pimaricin. Thus, the cultured sample from NBRC 12746(T) was analyzed for the production of polyene compounds. The strain produced an antifungal compound which displayed the UV absorption spectrum of tetraene macrolides. The structure determination based on the spectroscopic analysis of the purified compound resulted in the identification of a novel pimaricin analog JBIR-13 (1). This study therefore strongly suggested that a careful analysis of PKS-I genes can provide valuable information in the search of novel bioactive compounds within a class predicted from phylogenetic analysis.

Four novel glycosylated derivatives of versipelostatin (1), versipelostatins B-E (2-5), were isolated from the culture broth of Streptomyces versipellis 4083-SVS6. The inhibitory activities of the isolated compounds against the expression of molecular chaperone GRP78 induced by 2-deoxyglucose were evaluated. Of the five versipelostatin family members, 1 and 4 were the more potent with IC(50) values of 3.5 and 4.3 microM. These results suggest that the alpha-L-oleandropyranosyl (1-->4)-beta-D-digitoxopyranosyl residue in the sugar moiety may play an important role in down-regulating GRP78 expression induced by 2-deoxyglucose.

In the course of our screening program for active compounds that induce cell morphological changes of Saccharomyces cerevisiae, the culture broth of an entomopathogenic fungus Metarhizium sp. fE61 exhibited a unique morphological phenotype. We conducted an activity-guided isolation from the fermentation broth of Metarhizium sp. fE61 to yield two new macrolide compounds named JBIR-19 (1) and -20 (2) as active substances. Their structures were determined to be 24-membered macrolide analogs containing a 2-aminoethyl phosphate ester on the basis of NMR and other spectroscopic data. Compounds 1 and 2 induced striking elongated morphology of S. cerevisiae at concentrations of 3.1 and 13 microM, but showed weak antiyeast activity at MICs of 200 and >200 microM, respectively.

Two novel compounds, JBIR-07 (1) and -08 (2), were isolated from a large-scale culture of Streptomyces versipellis 4083-SVS6. These compounds were determined to be novel decanedienamide derivatives, (6E, 8Z)-3-hydroxy-8-(hydroxymethyl)-2,6-dimethyldeca-6,8-dienamide (1) and (6Z, 8E)-3-hydroxy-6-(hydroxymethyl)-2,8-dimethyldeca-6,8-dienamide (2), based on spectroscopic data.

A novel versipelostatin (1) analogue, versipelostatin F (2) was isolated from Streptomyces versipellis 4083-SVS6. The structure of 2 was determined by the analyses of the spectroscopic data. Compound 2 inhibited the expression of GRP78 induced by 2-deoxyglucose with an IC(50) value of 0.3 muM, which is 10-times more potent compared with that of 1.

A novel compound of antimycin family, JBIR-06 (1), was isolated from Streptomyces sp. ML55. The structure of 1 was established as a twelve-membered macrocyclic skeleton with a 3-(formylamino)-2-hydroxybenzamide based on the spectroscopic data. Compound 1 inhibited the expression of GRP78 induced by 2-deoxyglucose at the IC50 value of 250 nM.

A new indole-diterpene, JBIR-03 (1), was isolated from the fungus Dichotomomyces cejpii var. cejpii NBRC 103559 and its structure was determined based on the spectroscopic data. 1 exhibited anti-MRSA (methicillin-resistant Staphylococcus aureus) activity and antifungal activity against apple Valsa canker-causing fungus, Valsa ceratosperma, while it exhibited no toxicity towards human cancer cells.

In the course of our screening program for regulators of the expression of GRP78 molecular chaperone, JBIR-04 (1) and -05 (2) were isolated from Streptomyces violaceoniger 4541-SVS3 as congeners of prunustatin A (3). The structures of 1 and 2 were determined by the analyses of the spectroscopic data. These compounds mainly consist of an amino acid and amino acid derived alpha-hydroxy acid residues. 1 and 2 inhibited the expression of GRP78 induced by 2-deoxyglucose in human fibrosarcoma HT1080 cells, but their activities were highly reduced compared with those of 3 and SW-163A.

A new member of the piericidin family, JBIR-02, was isolated from mycelium of Streptomyces sp. ML55 together with two known piericidin derivatives, piericidin A(1) and IT-143-B. The structure was determined on the basis of spectroscopic data. JBIR-02 inhibited nuclear export of beta-arrestin in HeLa cells at the concentration of 20 microM.

A new polypropionate alloaureothin (1) possessing a nitro group, together with a known polypropionate aureothin (2), was isolated from mycelium of Streptomyces sp. MM23. The structure was determined on the basis of spectroscopic data. 1 exhibited growth inhibitory effect against human fibrosarcoma HT1080 cells with an IC50 value of 30 microM.

Agarwood, one of the valuable non-timber products in tropical forest, is a fragrant wood, whose ethereal fragrance has been prized in Asia for incense in ceremony, as well as sedatives in traditional medicine. We separated the 70% EtOH extract of Vietnamese agarwood, which showed significant induction effect on brain-derived neurotrophic factor (BDNF) mRNA expression in rat cultured neuronal cells, to isolate a new compound and a 2-(2-phenylethyl)chromone derivative. The new compound was determined to be a spirovetivane-type sesquiterpene, (4R,5R,7R)-1(10)-spirovetiven-11-ol-2-one, by spectroscopic data and showed induction effect of BDNF mRNA.

Ten new furanocassane-type diterpenes named, caesalpinins H-P (1-9) and norcaesalpinin F (10), were isolated from the CH(2)Cl(2) extract of the seed kernels of Caesalpinia crista, together with 13 known diterpenes. Their structures were determined based on the spectroscopic analysis. Among the isolated compounds, caesalpinin N (7) represents the first example of furanocassane-type diterpene possessing an aldehyde group at C-14.

From the MeOH extract of the flowers of Chrysanthemum sinense, a new flavone glucoside, acacetin 7- O-(3- O-acetyl- beta- D-glucopyranoside), has been isolated together with 27 known compounds including flavonoids, caffeoylquinic acid derivatives, phenolics, and a monoterpenoid glucoside. Their structures were elucidated on the basis of spectroscopic data. Compounds and displayed significant xanthine oxidase inhibitory activity in a concentration-dependent manner, and compounds and showed more potent inhibitory activity, with IC50 values ranging from 0.13 to 2.31 microM, than that of a positive control allopurinol (IC50=2.50 microM). The kinetic study indicated that and displayed competitive-type inhibition like that of allopurinol, while displayed a mixed-type inhibition.

The effects of acacetin (1) and 4,5-O-dicaffeoylquinic acid methyl ester (2), compounds contained in the flowers of Chrysanthemum sinense SABINE, on the serum uric acid level were investigated using the rats pretreated with the uricase inhibitor potassium oxonate as an animal model for hyperuricemia. When administered per orally at doses of 20 and 50 mg/kg, 1 reduced the serum uric acid level by 49.9 and 63.9%, respectively and 2 reduced the level by 31.2 and 44.4%, respectively. On the other hand, when the same doses were given intraperitoneally, both of compounds also exhibited a dose-dependent and more marked reduction of the serum uric acid level (% reduction at 20 and 50 mg/kg were 63.0 and 95.1% in 1, respectively and 66.9 and 86.5% in 2, respectively). Furthermore, the compounds 1 and 2 inhibited the rat liver xanthine oxidase activity with IC(50) values of 2.22 muM and 5.27 muM, respectively. These results demonstrated the hypouricemic action of 1 and 2, which may be attributable to their xanthine oxidase inhibitory activity.

A methanolic extract of Nepalese propolis yielded 10 new open-chain neoflavonoids (1-10), a new chalcone (11), and eight previously reported compounds (12-19). Their structures were determined on the basis of spectroscopic data and chemical conversion. The isolated compounds other than 5, 8, and 16 showed dose-dependent inhibitory activities on nitric oxide production in lipopolysaccharide-activated macrophage-like J774.1 cells and were more active than a positive control, N(G)-monomethyl-L-arginine (IC(50), 27.1 microM). The most potent activities, of 6 and 7 (IC(50), 0.5 microM), were greater than another positive control, caffeic acid phenethyl ester (IC(50), 4.8 microM).

From the water extract of Brazilian Tabebuia avellanedae, two new iridoids (1, 2) and a new phenylethanoid glycoside (3) have been isolated together with twelve known compounds (4-15). Their structures were determined based on the spectroscopic data. The isolated compounds inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophage-like J774.1 cells. Compounds 1, 3, 10, 11, and 12 showed inhibitory activities more potent (IC50, 13.8-26.1 microg/ml) than a positive control N(G)-monomethyl-L-arginine (L-NMMA; IC50, 27.4 microg/ml).

The CH2Cl2 extract of the seed kernels of Caesalpinia crista, which exhibited promising antimalarial activity against Plasmodium berghei-infected mice in vivo, was examined and resulted in the isolation of seven new furanocassane-type diterpenes [caesalpinins C-G (1-5) and norcaesalpinins D and E (6, 7)] together with norcaesalpinins A-C (8-10) and 11 known compounds (norcaesalpinins A-C, 2-acetoxy-3-deacetoxycaesaldekarin e, caesalmin B, caesaldekarin e, caesalpin F, 14(17)-dehydrocaesalpin F, 2-acetoxycaesaldekarin e, 7-acetoxybonducellpin C, and caesalmin G). Their structures were determined on the basis of spectroscopic analysis. The isolated diterpenes showed significant dose-dependent inhibitory effects on Plasmodium falciparum FCR-3/A2 growth in vitro. Their IC50 values ranged from 90 nM to 6.5 microM, and norcaesalpinin E (7) showed the most potent inhibitory activity (IC50, 90 nM).