Concise Synthesis of Broussonone A.

A concise and expeditious approach to the total synthesis of broussonone A, a p-quinol natural compound, has been developed. The key features of the synthesis include the Grubbs II catalyst mediated cross metathesis of two aromatic subunits, and a chemoselective oxidative dearomatizationin the presence of two phenol moieties. Especially, optimization associated with the CM reaction of ortho-alkoxystyrenes was also studied, which are known to be ineffective for Ru-catalyzed metathesis reactions under conventional reaction conditions because ortho-alkoxy group could coordinate to the ruthenium center, resulting in the potential complication of catalyst inhibition.

Synthesis and anticancer activity of 4-aza-daurinol derivatives.

Daurinol, a natural aryl naphthalene lactone, has been reported to have antiproliferative activity against various cell lines, and has also been shown to be efficacious in an in vivo xenograft mouse model. In this study, we tried to discover a new scaffold that enables both rapid structure-activity relationship study of daurinol and scalable synthesis of active compounds. 4-Aza-daurinol, a bioisosterism-based scaffold of daurinol, was designed and 17 analogues were synthesized and evaluated against five representative cancer cell lines.

Inhibition of IRAK-4 activity for rescuing endotoxin LPS-induced septic mortality in mice by lonicerae flos extract.

Lonicerae flos extract (HS-23) is a clinical candidate currently undergoing Phase I trial in lipopolysaccharide (LPS)-injected healthy human volunteers, but its molecular basis remains to be defined. Here, we investigated protective effects of HS-23 or its major constituents on Escherichia coli LPS-induced septic mortality in mice. Intravenous treatment with HS-23 rescued LPS-intoxicated C57BL/6J mice under septic conditions, and decreased the levels of cytokines such as tumor necrosis factor α (TNF-α), interleukin (IL)-1β and high-mobility group box-1 (HMGB-1) in the blood.

Identification of chalcones as potent and selective PDE5A1 inhibitors.

Chalcones have an affinity for many receptors, enzymes, and transcription factors as flavonoid analogues. Their most studied pharmacological action is that of vasodilatation due to inhibition of phosphodiesterase 5A1 (PDE5A1). To this end, we have established a recursive partitioning model with 3 chemical descriptors for the prediction of compounds that can inhibit PDE5A1.

Synthesis and anti-platelet activity of obovatol derivatives.

Obovatol derivatives were synthesized and evaluated for anti-platelet activity. Three derivatives (1, 2, 4i) displayed equipotent activity to obovatol in arachidonic acid-induced platelet aggregation. An initial SAR study revealed that the introduction of alkoxy group in B ring could enhance inhibitory activity.

Discovery of a potent tubulin polymerization inhibitor: synthesis and evaluation of water-soluble prodrugs of benzophenone analog.

Prodrugs have proven to be very useful in enhancing aqueous solubility of sparingly water-soluble drugs, thereby increasing in vivo efficacy without a need of special excipients. In vitro and in vivo evaluations of a number of amino acid prodrugs of 1, a previously identified potent tubulin polymerization inhibitor and cytotoxic against various cancer cell lines led to the discovery of 3·HCl (l-valine attached) which is highly efficacious in mouse xenografts bearing human cancer. Pharmacokinetic analysis in rats revealed that compound 1 was released immediately upon administration of 3·HCl intravenously, with rapid clearance of 3·HCl indicating the effective cleavage of prodrug.

Identification of CKD-516: a potent tubulin polymerization inhibitor with marked antitumor activity against murine and human solid tumors.

Tubulin polymerization inhibitors had emerged as one of promising anticancer therapeutics because of their dual mechanism of action, i.e. apoptosis by cell-cycle arrest and VDA, vascular disrupting agent.

Discovery of potent, selective, and orally bioavailable PDE5 inhibitor: Methyl-4-(3-chloro-4-methoxybenzylamino)-8-(2-hydroxyethyl)-7-methoxyquinazolin-6-ylmethylcarbamate (CKD 533).

In a continuing effort to discover novel PDE5 inhibitors, we have successfully found quinazolines with 4-benzylamino substitution as potent and selective PDE5 inhibitors. Initial lead compound (1) was found to be easily metabolized when incubated with human liver microsomes mainly through C6 amide hydrolysis. Blocking of this metabolic hot spot led to discovery of 10 (CKD533) which is highly potent, selective and orally efficacious in conscious rabbit model for erectile dysfunction and now is undergoing preclinical toxicology study.

RhoB induces apoptosis via direct interaction with TNFAIP1 in HeLa cells.

RhoB, a tumor suppressor, has emerged as an interesting cancer target, and extensive studies aimed at understanding its role in apoptosis have been performed. In our study, we investigated the involvement of RhoB-interacting molecules in apoptosis. To identify RhoB-interacting proteins, we performed yeast-two hybrid screening assays using RhoB as a bait and isolated TNFAIP1, a TNFalpha-induced protein containing the BTB/POZ domain.

Quinazolines as potent and highly selective PDE5 inhibitors as potential therapeutics for male erectile dysfunction.

In an effort to minimize side effects associated with low selectivity against PDE isozymes, we have successfully identified a series of 6,7,8-substituted quinzaolines as potent inhibitors of PDE5 with high level of isozyme selectivity, especially against PDE6 and PDE11. PDE5 potency and isozyme selectivity of quinazolines were greatly improved with substitutions both at 6- and 8-position. The synthesis, structure-activity relationships and in vivo efficacy of this novel series of potent PDE5 inhibitors are described.

Isolation and identification of eukaryotic initiation factor 4A as a molecular target for the marine natural product Pateamine A.

Natural products continue to demonstrate their utility both as therapeutics and as molecular probes for the discovery and mechanistic deconvolution of various cellular processes. However, this utility is dampened by the inherent difficulties involved in isolating and characterizing new bioactive natural products, in obtaining sufficient quantities of purified compound for further biological studies, and in developing bioactive probes. Key to characterizing the biological activity of natural products is the identification of the molecular target(s) within the cell.

Synthesis of novel diaryl ethers and their evaluation as antimitotic agents.

A series of novel diaryl ethers possessing various functional groups were synthesized and evaluated for antiproliferative activity in human myeloid leukemia HL-60 cells. Among the compounds examined, compounds 10, 17, 20, 24, and 33 showed moderate to potent antiproliferative activity. These derivatives were further examined in terms of their abilities to inhibit tubulin polymerization; however, all of the tested compounds were relatively ineffective.

Inhibition of eukaryotic translation initiation by the marine natural product pateamine A.

Translation initiation in eukaryotes is accomplished through the coordinated and orderly action of a large number of proteins, including the eIF4 initiation factors. Herein, we report that pateamine A (PatA), a potent antiproliferative and proapoptotic marine natural product, inhibits cap-dependent eukaryotic translation initiation. PatA bound to and enhanced the intrinsic enzymatic activities of eIF4A, yet it inhibited eIF4A-eIF4G association and promoted the formation of a stable ternary complex between eIF4A and eIF4B.

Total synthesis and antiangiogenic activity of cyclopentane analogues of fumagillol.

Novel cyclopentane analogues of fumagillol were synthesized and their endothelial cell proliferation inhibitory activities were evaluated. The cyclopentane-fumagillol derivatives were synthesized from (-)-2,3-O-isopropylidene-D-erythronolactone via stereoselective glycolate Claisen rearrangement and intramolecular ester enolate alkylation as key steps.

Functional divergency oriented synthesis of azoninones as the key intermediates for bioactive indolizidine alkaloids analogs.

A functional divergency oriented synthetic approach to the azoninone (9-membered lactams), key intermediate for the indolizidine alkaloids library, using amide enolate induced aza-Claisen rearrangement has been achieved.

Syntheses and anti-MRSA activities of the C3 analogs of mansonone F, a potent anti-bacterial sesquiterpenoid: insights into its structural requirements for anti-MRSA activity.

Syntheses and excellent anti-MRSA activities of the mansonone F analogs are reported. In addition, the minimal structural requirements for its anti-MRSA activities as well as its structure-activity relationship including the C3 substituents effects on anti-MRSA activity are also described. In particular, this study revealed that both ortho-quinone and tricyclic systems of mansonone F are essential for anti-MRSA activities.

Evidence for separate binding and scaffolding domains in the immunosuppressive and antitumor marine natural product, pateamine a: design, synthesis, and activity studies leading to a potent simplified derivative.

Pateamine A (PatA), a marine metabolite from Mycale sp., is a potent inhibitor of the intracellular signal transduction pathway emanating from the T-cell receptor leading to the transcription of cytokines such as interleukin-2 (IL-2). On the basis of the structure of PatA and initial biological results, a hypothesis was developed regarding the presence of distinct binding and scaffolding domains in the PatA structure with respect to interactions with its putative cellular receptor(s).

CoMFA and CoMSIA 3D QSAR studies on pimarane cyclooxygenase-2 (COX-2) inhibitors.

Comparative molecular field analysis and comparative molecular similarity indices analysis were performed on twenty five analogues of pimarane COX-2 inhibitor to optimize their cyclooxygenase-2 (COX-2) selective anti-inflammatory activities.

5-Demethoxyfumagillol, a potent angiogenesis inhibitor isolated from Aspergillus fumigatus.

A novel angiogenesis inhibitor, 5-demethoxyfumagillol (1), was obtained by isolation, purification and saponification of cultured broth of Aspergillus fumigatus. The structure was assigned as (3R,4R,6R)-4-[(2R,3R)-2-methyl-3-(3-methyl-but-2-enyl)-oxiranyl]-1-oxa-spiro[2,5]octan-6-ol (1) by spectroscopic analysis and confirmed by independent synthesis from fumagillol (3). In addition, 6-O-(chloroacetylcarbamoyl)-5-demethoxyfumagillol (7) showed a potential anti-angiogenic activity in CAPE cells in vitro.