DNA Topoisomerase Inhibitory Activity of Constituents from the Fruits of Illicium verum.

Three new compounds, a sesquilignan (1) and two glucosylated phenylpropanoids (2, 3), and seven known compounds (4-10), were isolated from the fruits of Illicium verum HOOK. FIL. (Illiciaceae).

Engineering an FMN-based iLOV protein for the detection of arsenic ions.

Over the past few decades, genetically encoded fluorescent proteins have been widely used as efficient probes to explore and investigate the roles of metal ions in biological processes. The discovery of small FMN-based fluorescent proteins, such as iLOV and FbFP, has enabled researchers to exploit these fluorescent reporter proteins for metal-sensing applications. In this study, we report the inherent binding properties of iLOV towards arsenic ions.

DNA Topoisomerase Inhibitory Activity of Constituents from the Flowers of Inula japonica.

Fourteen compounds were isolated from the flowers of Inula japonica THUNB. (Asteraceae), including two new compounds, (1S,2S,4S,5S,8S,10R)-2-acetoxy-4,3-dihydroxy-pseudoguai-7(11)-en-12,8-olide (1) and (1S,2S,4S,5S,8S,10R)-2,4,13-trihydroxy-pseudoguai-7(11)-en-12,8-olide (2), and twelve known compounds, budlein B (3), 6β-hydroxytomentosin (4), 6-deacetoxybritanin (5), 4-epipulchellin (6), britanin (7), tomentosin (8), (+)-dihydroquercetin (9), (-)-syringaresinol (10), quercetagetin 3,4'-dimethyl ether (11), luteolin (12), britanin G (13) and inuchinenolide C (14). Structures of 1 and 2 were determined based on one and two dimensional (1D)- and (2D)-NMR data and Mosher's esterification method.

FMN-Based Fluorescent Proteins as Heavy Metal Sensors Against Mercury Ions.

Bacterial light-oxygen-voltage-sensing photoreceptor-derived flavin mononucleotide (FMN)- based fluorescent proteins act as a promising distinct class of fluorescent proteins utilized for various biomedical and biotechnological applications. The key property of its independency towards oxygen for its chromophore maturation has greatly helped this protein to outperform the other fluorescent proteins such as GFP and DsRed for anaerobic applications. Here, we describe the feasibility of FMN-containing fluorescent protein FbFP as a metal-sensing probe by measuring the fluorescence emission changes of a protein with respect to the concentration of metal ions.

Incorporating unnatural amino acids to engineer biocatalysts for industrial bioprocess applications.

The bioprocess engineering with biocatalysts broadly spans its development and actual application of enzymes in an industrial context. Recently, both the use of bioprocess engineering and the development and employment of enzyme engineering techniques have been increasing rapidly. Importantly, engineering techniques that incorporate unnatural amino acids (UAAs) in vivo has begun to produce enzymes with greater stability and altered catalytic properties.

Unnatural amino acid mutagenesis-based enzyme engineering.

Traditional enzyme engineering relies on substituting one amino acid by one of the other 19 natural amino acids to change the functional properties of an enzyme. However, incorporation of unnatural amino acids (UAAs) has been harnessed to engineer efficient enzymes for biocatalysis. Residue-specific and site-specific in vivo incorporation methods are becoming the preferred approach for producing enzymes with altered or improved functions.

Engineering lead-sensing GFP through rational designing.

Lead is one of the most hazardous metals ubiquitous in the environment, causing serious health hazards to organisms. Recently, fluorescent proteins such as GFP and Dsred were utilized for the development of reagent-less rapid metal sensors. Here, we demonstrate the development of a lead-sensing GFP that is highly sensitive to lead at micro molar concentrations.

A New-Generation Fluorescent-Based Metal Sensor - iLOV Protein.

The iLOV protein belongs to a family of blue-light photoreceptor proteins containing a lightoxygen- voltage sensing domain with a noncovalently bound flavin mononucleotide (FMN) as its chromophore. Owing to advantages such as its small size, oxygen-independent nature, and pH stability, iLOV is an ideal candidate over other reporter fluorescent proteins such as GFP and DsRed. Here, for the first time, we describe the feasibility of applying LOV domain-based fluorescent iLOV as a metal sensor by measuring the fluorescence quenching of a protein with respect to the concentration of metal ions.

Synthesis of novel and diverse mollugin analogues and their antibacterial and antioxidant activities.

Novel and diverse mollugin analogues (1-12) were synthesized using PhB(OH)2/AcOH-mediated electrocyclization reaction as a key step. The newly synthesized compounds were screened for antioxidant and antibacterial activities. Compounds 1, 2, 5, 6, 8, and 10-12 showed high antioxidant activities in DPPH inhibition (IC50=0.

Inhibition of DNA topoisomerases I and II of compounds from Reynoutria japonica.

Three anthraquinones (1, 2 and 4), three stilbenes (5, 6 and 7) and 3,5-dihydroxybenzyl alcohol (3) were isolated from Reynoutria japonica. Their structures were identified as emodin (1), emodin-8-O-β-D-glucoside (2), 3,5-dihydroxybenzyl alcohol (3), citreorosein (4), cis-resveratrol (5), trans-resveratrol (6) and trans-resveratrol-5-O-β-D-glucopyranoside (7) by comparing their physicochemical and spectral data with published data. Compound 3 was isolated for the first time from the Polygonaceae family.

New topoisomerases inhibitors: synthesis of rutaecarpine derivatives and their inhibitory activity against topoisomerases.

A series of rutaecarpine derivatives were prepared by employing previously reported methods and their inhibitory activities against topoisomerase I and II were evaluated. Among them, strongly cytotoxic 10-bromorutaecarpine and 3-chlororutaecarpine showed strong inhibitory activities against topo I and II.

Constituents with DNA topoisomerases I and II inhibitory activity and cytotoxicity from the roots of Rubia cordifolia.

Activity-directed isolation of the ethyl acetate fraction from the roots of Rubia cordifolia resulted in the identification of a new anthraquinone, 1,3,6-trihydroxy-2-hydroxymethyl-9,10-anthraquinone-3- O- α- L-rhamnopyranosyl-(1 → 2)- β-D-(6'-O-acetyl)-glucopyranoside (1), two new dihydronaphtoquinones, 1,4-dihydroxy-2-carbomethoxy-3-prenylnaphthalene-1-O- β-D-glucopyranoside (2) and mollugin-1-O- β- D-glucopyranoside (3), and a new monoterpenoid, 3 R,3a S,4 R,6a R-3,4,6-tris(hydroxymethyl)-3,3a,4,6a-tetrahydro-2 H-cyclopenta[ B]furan-2-one (4), together with nine known compounds (5-13). The structures of these compounds were elucidated on the basis of spectroscopic evidence. In addition, their DNA topoisomerases I and II inhibitory activity and cytotoxicity were measured.

Inhibition of DNA topoisomerases I and II and cytotoxicity of compounds from Ulmus davidiana var. japonica.

Twenty five compounds including ten triterpenes (1-3, 5-11), six flavonoids (12-15, 24, 25), five lignans (17, 18, 21-23), two butenyl clohexnone glycosides (19-20), one fructofuranoside (16) and one fatty acid (4) were isolated from the roots of Ulmus davidiana var. japonica. The structures of those compounds were identified by comparing their physicochemical and spectral data with those of published in literatures.

Synthesis and pharmacological evaluation of new methyloxiranylmethoxyxanthone analogues.

In order to develop potential anti-cancer agents that act on topoisomerase II and DNA, we have synthesized 12 new xanthone derivatives. In the cytotoxicity test, compounds 17 and 31 exhibited 2- to 7-fold stronger inhibitory activity than adriamycin against most cancer cell lines tested. Halohydrin group-tethered compounds 19, 21 and 27 showed comparable topoisomerase II inhibitory activity to etoposide at 100 microM concentration.

Mutation spectra induced by adozelesin in the supF gene of human XP-A fibroblasts.

Adozelesin is a synthetic analog of the antitumor antibiotic, CC-1065, which alkylates N3 of adenine in the minor DNA groove in a sequence-specific manner. Here we tested the mutation spectra induced by adozelesin in the supF gene of human XP-A fibroblasts using a shuttle vector assay. Adozelesin primarily induces mutations via an A --> T transversion and a single base insertion.

2,6-Dithienyl-4-furyl pyridines: Synthesis, topoisomerase I and II inhibition, cytotoxicity, structure-activity relationship, and docking study.

For the development of novel antitumor agents, 2,6-dithienyl-4-furyl pyridine derivatives were prepared and evaluated for their topoisomerase I and II inhibitory activity as well as cytotoxicity against several human cancer cell lines. Among the 21 prepared compounds, compound 24 exhibited strong topoisomerase I inhibitory activity. In addition, a docking study with topoisomerase I and compound 24 was performed.

Inhibition of DNA topoisomerases I and II and cytotoxicity by lignans from Saururus chinensis.

Thirteen lignans, erythro-austrobailignan-6 (1), meso-dihydroguaiaretic acid (2), sauchinone (3), 1'-epi-sauchinone (4), saucerneol D (5), manassantin B (6), manassantin A (7), nectandrin B (8), machilin D (9), saucerneol F (10), saucerneol G (11), saucerneol H (12) and saucerneol I (13), were isolated from the ethyl acetate extract of the roots of Saururus chinensis. Among these compounds, 5 showed potent inhibitory activities against DNA topoisomerase I and II, and 5, 6, 7 and 10 showed mild cytotoxicities against HT-29 (IC(50) values; 13, 12, 11, and 10 microM, respectively) and HepG2 cell lines (IC(50) values; 16, 11, 12, and 11 microM, respectively).

Topoisomerase I and II inhibitory constituents from the bark of Tilia amurensis.

Two coumarins (1 and 6), one flavan-3-ol (2), one fatty acid (3), and two lignan glycosides (4 and 5) were isolated from the EtOAc and CH(2)Cl(2) extract of the bark of Tilia amurensis. Their chemical structures were identified by comparing their physicochemical and spectral data with those of published in literatures. Compounds 4, 5, and 6 were isolated from Tilia genus for the first time.

Mutation spectra induced by 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide in the supF gene of human XP-A fibroblasts.

1-Nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide are oxidative metabolites that are responsible for the mutagenicity of 1-nitropyrene. In this study, the mutation spectra induced by oxidative metabolites in human cells were determined using a shuttle vector assay. The mutation frequencies induced by 1-nitropyrene 9,10-oxide were 2-3 times higher than those induced by 1-nitropyrene 4,5-oxide.

Anticancer constituents from the roots of Rubia cordifolia L.

Activity-directed isolation of the methylene chloride fraction of the roots of Rubia cordifolia L. resulted in the identification of a new epoxymollugin (3) and eight known compounds (1, 2, 4-9). The structures of the compounds were elucidated from chemical and spectroscopic evidence.

Cytotoxic and DNA topoisomerases I and II inhibitory constituents from the roots of Aralia cordata.

Bioactivity-guided fractionation, based on the DNA topoisomerase inhibitory activity, lead to the isolation of five compounds (1-5) from the methylene chloride extract of the roots of Aralia cordata Thunb. (Araliaceae). These compounds were identified as ent-pimara-8(14), 15-dien-19-oic acid (1), ent-pimara-8(14), 15-dien-18-oic acid (2), 16alpha-hydrogen-17-isovaleryloxy-ent-kauran-19-oic acid (3), 16alpha-hydroxy-17-isovaleryloxy-ent-kauran-19-oic acid (4) and dehydrofalcarindiol-8-acetate (5) from their spectral data.

Synthesis of 2,6-diaryl-substituted pyridines and their antitumor activities.

For the development of novel antitumor agents, we designed and synthesized 2,6-diaryl-substituted pyridine derivatives bearing three aryl groups, which are the bioisosteres of terpyridine, and evaluated their biological activities. Most of the 18 prepared compounds showed moderate cytotoxicity against several human cancer cell lines. From the structure-activity relationships we may conclude that the number of aryl groups employed would be critical for their biological activities.

2,4,6-Trisubstituted pyridines: Synthesis, topoisomerase I and II inhibitory activity, cytotoxicity, and structure-activity relationship.

Designed and synthesized were a series of pyridines substituted at 2, 4, and 6 positions with various 5- or 6-memberd heteroaromatics as antitumor agents. They were evaluated their topoisomerase I and II inhibitory activities along with cytotoxicities against several human cancer cell lines. Among the prepared compounds, 10-20 showed significant topoisomerase I or II inhibitory activities, and 21-26 showed considerable cytotoxicities against several human cancer cell lines.

Cytotoxic constituents isolated from the fruit bodies of Hypsizigus marmoreus.

The bioactivity-guided fractionation of chloroform extracts of the fruit bodies of Hypsizigus marmoreus led to our isolation of (22E,24R)-ergosta-7,22-diene-3beta,5alpha,6beta-triol (1), ergosterol-3-O-beta-D-glucopyranoside (2), 5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (3), hypsiziprenol A9 (4), hypsiziprenol AA8 (5), hypsiziprenol AA9 (6) and hypsiziprenol BA10 (7). Among these seven isolates, compound 2 was identified for the first time from this plant. All compounds (1-7) exhibited moderate cytotoxicity towards cultured human colon carcinoma (HT-29), human breast carcinoma (MCF-7) and human hepatoblastoma (HepG-2) cell lines.