Botanical Ingredient Forensics: Detection of Attempts to Deceive Commonly Used Analytical Methods for Authenticating Herbal Dietary and Food Ingredients and Supplements.

Botanical ingredients are used widely in phytomedicines, dietary/food supplements, functional foods, and cosmetics. Products containing botanical ingredients are popular among many consumers and, in the case of herbal medicines, health professionals worldwide. Government regulatory agencies have set standards (collectively referred to as current Good Manufacturing Practices, cGMPs) with which suppliers and manufacturers must comply.

Cinnamon - Differentiation of Four Species by Linking Classical Botany to an Automated Chromatographic Authentication System.

One of the world's oldest spices, cinnamon is also one of the most popular. Species of the genus offer a variety of extractable oils with aroma and flavor characteristics of importance to the flavor industry, so differentiating cinnamon samples for culinary-based applications is very important. Cinnamon also has reported health benefits associated with specific phytochemical constituents, but its composition can vary greatly depending on species and source region.

A matrix-focused structure-activity and binding site flexibility study of quinolinol inhibitors of botulinum neurotoxin serotype A.

Our initial discovery of 8-hydroxyquinoline inhibitors of BoNT/A and separation/testing of enantiomers of one of the more active leads indicated considerable flexibility in the binding site. We designed a limited study to investigate this flexibility and probe structure-activity relationships; utilizing the Betti reaction, a 36 compound matrix of quinolinol BoNT/A LC inhibitors was developed using three 8-hydroxyquinolines, three heteroaromatic amines, and four substituted benzaldehydes. This study has revealed some of the most effective quinolinol-based BoNT/A inhibitors to date, with 7 compounds displaying IC values ⩽1μM and 11 effective at ⩽2μM in an ex vivo assay.

Fungal bis-Naphthopyrones as Inhibitors of Botulinum Neurotoxin Serotype A.

An in silico screen of the NIH Molecular Library Small Molecule Repository (MLSMR) of ∼350000 compounds and confirmatory bioassays led to identification of chaetochromin A (1) as an inhibitor of botulinum neurotoxin serotype A (BoNT A). Subsequent acquisition and testing of analogues of 1 uncovered two compounds, talaroderxines A (2) and B (3), with improved activity. These are the first fungal metabolites reported to exhibit BoNT/A inhibitory activity.

Separation of Betti Reaction Product Enantiomers: Absolute Configuration and Inhibition of Botulinum Neurotoxin A.

The racemic product of the Betti reaction of 5-chloro-8-hydroxyquinoline, benzaldehyde and 2-aminopyridine was separated by chiral HPLC to determine which enantiomer inhibited botulinum neurotoxin serotype A. When the enantiomers unexpectedly proved to have comparable activity, the absolute structures of (+)-(R)-1 and (-)-(S)-1 were determined by comparison of calculated and observed circular dichroism spectra. Molecular modeling studies were undertaken in an effort to understand the observed bioactivity and revealed different ensembles of binding modes, with roughly equal binding energies, for the two enantiomers.

Isoflavonoids and coumarins from Glycyrrhiza uralensis: antibacterial activity against oral pathogens and conversion of isoflavans into isoflavan-quinones during purification.

Phytochemical investigation of a supercritical fluid extract of Glycyrrhiza uralensis has led to the isolation of 20 known isoflavonoids and coumarins, and glycycarpan (7), a new pterocarpan. The presence of two isoflavan-quinones, licoriquinone A (8) and licoriquinone B (9), in a fraction subjected to gel filtration on Sephadex LH-20 is due to suspected metal-catalyzed oxidative degradation of licoricidin (1) and licorisoflavan A (2). The major compounds in the extract, as well as 8, were evaluated for their ability to inhibit the growth of several major oral pathogens.

Chemical modification of the insecticidal briantheins X and Y.

Manipulation of the allylic chloride functionality in briantheins X and Y provided 10 new analogues of these gorgonian diterpenes as part of a continuing study of structure-activity relationships in this family of insecticidal compounds. Modified Finkelstein reaction conditions led not only to halogen substitution products but also to rearrangement, dehydrohalogenation, and dehydration products. None of the new compounds showed superior insecticidal activity to brianthein X or Y, although most did result in lower weight gains versus controls.

Cellular inhibition of checkpoint kinase 2 (Chk2) and potentiation of camptothecins and radiation by the novel Chk2 inhibitor PV1019 [7-nitro-1H-indole-2-carboxylic acid {4-[1-(guanidinohydrazone)-ethyl]-phenyl}-amide].

Chk2 is a checkpoint kinase involved in the ataxia telangiectasia mutated pathway, which is activated by genomic instability and DNA damage, leading to either cell death (apoptosis) or cell cycle arrest. Chk2 provides an unexplored therapeutic target against cancer cells. We recently reported 4,4'-diacetyldiphenylurea-bis(guanylhydrazone) (NSC 109555) as a novel chemotype Chk2 inhibitor.

Cytotoxic and HIF-1alpha inhibitory compounds from Crossosoma bigelovii.

Cytotoxicity-guided fractionation of an organic solvent extract of the plant Crossosoma bigelovii led to the discovery of a new strophanthidin glycoside (1) and two new 2-methylchromone glycosides (2 and 3). Also isolated were the known chromones eugenin and noreugenin, the indole alkaloid ajmalicine, the dibenzylbutane lignan secoisolariciresinol, the dibenzylbutyrolactone lignan matairesinol, and the furanone 5-tetradec-5-enyldihydrofuran-2-one. Further investigation into the biological properties of strophanthidin glycosides revealed a connection between inhibition of HIF-1 activation and the glycosylation of the genin.

Inhibitors of the NF-kappaB activation pathway from Cryptocarya rugulosa.

The nuclear factor-kappaB (NF-kappaB) signaling pathway is constitutively active in many types of cancers and is a potential therapeutic target. Using a cell-based assay for stability of inhibitor of kappa B (IkappaB), a critical regulator of NF-kappaB activity, we found that an organic solvent extract of the plant Cryptocarya rugulosa inhibited constitutive NF-kappaB activity in human lymphoma cell lines. The active components were identified as rugulactone, a new alpha-pyrone (1), and the known cryptocaryone (2).

Induction of apoptosis in human cancer cells by candidaspongiolide, a novel sponge polyketide.

Background: Candidaspongiolide (CAN), a novel polyketide from a marine sponge, is the active component of a mixture that was found to be potently cytotoxic in the National Cancer Institute's 60-cell-line screen.

Methods: Effects of CAN on U251 glioma and HCT116 colorectal cancer cells and on normal fibroblasts were assessed using radiolabeling studies to measure protein synthesis, clonogenic assays to measure cell survival, flow cytometry of annexin V- and propidium iodide-stained cells to measure apoptosis, and western blots in the presence or absence of specific inhibitors to assess accumulation and phosphorylation of potential downstream target proteins.

Results: CAN inhibited protein synthesis and potently induced apoptosis in both U251 and HCT116 cells, the latter in part by a caspase 12-dependent pathway.

Arylstibonic acids: novel inhibitors and activators of human topoisomerase IB.

Human topoisomerase IB (hTopo) forms a covalent phosphotyrosyl linkage with the DNA backbone, and controls genomic DNA topology by relaxing DNA supercoils during the processes of DNA replication, transcription, chromosome condensation and decondensation. The essential role of hTopo in these processes has made it a preeminent anticancer drug target. We have screened a small library of arylstibonic acids for their effects on plasmid supercoil relaxation catalyzed by hTopo.

Separation and SAR study of HIF-1alpha inhibitory tubulosines from Alangium cf. longiflorum.

A crude organic solvent extract of Alangium cf. longiflorum exhibited potent inhibition of hypoxia-induced HIF-1 transcriptional activity in human U251 glioma cells. Dereplication and bioactivity-guided fractionation, including Sephadex LH-20 and chiral HPLC chromatographies, led to the isolation of tubulosine ( 1), 9-desmethyltubulosine ( 2), and isotubulosine ( 3).

Potent inhibition of human apurinic/apyrimidinic endonuclease 1 by arylstibonic acids.

Human apurinic/apyrimidinic endonuclease (Ape1) plays an important role by processing the >10,000 highly toxic abasic sites generated in the genome of each cell every day. Ape1 has recently emerged as a target for inhibition, in that its overexpression in tumors has been linked with poor response to both radiation and chemotherapy and lower overall patient survival. Inhibition of Ape1 using siRNA or the expression of a dominant-negative form of the protein has been shown to sensitize cells to DNA-damaging agents, including various chemotherapeutic agents.

Identification of a Bis-guanylhydrazone [4,4'-Diacetyldiphenylurea-bis(guanylhydrazone); NSC 109555] as a novel chemotype for inhibition of Chk2 kinase.

Chk2 is a protein kinase involved in the ATM-dependent checkpoint pathway (http://discover.nci.nih.

Candidaspongiolides, distinctive analogues of tedanolide from sponges of the genus Candidaspongia.

Fractionation of cytotoxic extracts of specimens of a newly described sponge genus, Candidaspongia, has yielded the candidaspongiolides (3), a complex mixture of acyl esters of a macrolide related to tedanolide. The general structure of the candidaspongiolides was determined by analyses of various 2D NMR and MS data sets. The acyl ester components were identified by GC-MS analysis of the derived fatty acid methyl esters.

Structural assignment of poecillastrins B and C, macrolide lactams from the deep-water Caribbean sponge Poecillastra species.

Two new chondropsin-type macrolide lactams, poecillastrins B (1) and C (2), were isolated from aqueous extracts of the marine sponge Poecillastra sp. These trace metabolites were isolated in low yield (400-600 microg), and their structures were determined primarily by analysis of NMR data acquired using a cyrogenically cooled probe. High-quality 1D and 2D NMR data sets allowed complete assignment of the spectroscopic data and defined the new structures as 35-membered ring analogues of poecillastrin A (3).

Identification of a new natural camptothecin analogue in targeted screening for HIF-1alpha inhibitors.

Screening to detect compounds that inhibit the HIF-1alpha transcriptional activation pathway identified an extract of Ophiorrhiza trichocarpon for investigation. A high throughput dereplication strategy was employed, involving chromatography with spectral data acquisition supported by bioactivity testing and literature referencing, which led to rapid identification of camptothecin (1) and three analogues (2 - 4) as the active compounds. 9,10-Methylenedioxy-(20S)-camptothecin (4) was found for the first time from a plant.

Cell type-specific, topoisomerase II-dependent inhibition of hypoxia-inducible factor-1alpha protein accumulation by NSC 644221.

Purpose: The discovery and development of small-molecule inhibitors of hypoxia-inducible factor-1 (HIF-1) is an attractive, yet challenging, strategy for the development of new cancer therapeutic agents. Here, we report on a novel tricyclic carboxamide inhibitor of HIF-1alpha, NSC 644221.

Experimental Design: We investigated the mechanism by which the novel compound NSC 644221 inhibited HIF-1alpha.

Targeting the PAS-A domain of HIF-1alpha for development of small molecule inhibitors of HIF-1.

Hypoxia inducible factor-1 (HIF-1) is a master regulator of cellular adaptation to oxygen deprivation and activates transcription of genes involved in tumor metabolism, angiogenesis, invasion and metastasis, all of which are implicated in cancer progression. Several domains of HIF-1alpha mediate protein-protein interaction, which is essential for the formation of the active heterodimer with HIF-1beta. Targeting specific domains of HIF-1alpha might lead to the identification of more selective inhibitors.

Antifungal flavonoids from Hildegardia barteri.

A new isoflavan, (3R)-6,2'-dihydroxy-7-methoxy-4',5'-methylenedioxyisoflavan, hildegardiol (1), and two known flavonoids, 2-hydroxymaackiain (2) and farrerol (3), were isolated from the antifungal root extract of Hildegardia barteri. The pterocarpan 2 was largely responsible for the observed antifungal activity.

Echinomycin, a small-molecule inhibitor of hypoxia-inducible factor-1 DNA-binding activity.

The identification of small molecules that inhibit the sequence-specific binding of transcription factors to DNA is an attractive approach for regulation of gene expression. Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that controls genes involved in glycolysis, angiogenesis, migration, and invasion, all of which are important for tumor progression and metastasis. To identify inhibitors of HIF-1 DNA-binding activity, we expressed truncated HIF-1alpha and HIF-1beta proteins containing the basic-helix-loop-helix and PAS domains.

Aspirochlorine class compounds from Aspergillus flavus inhibit azole-resistant Candida albicans.

Dereplication of the antifungal extracts of Aspergillus flavus indicated that the primary antifungal compound present was the known aspirochlorine (1). Preparative isolation work resulted in the identification of the new compounds tetrathioaspirochlorine (2) and cyclo(D-N-methyl-Leu-L-Trp) (3).