Steven M Swanson

University of Wisconsin–Madison, Madison, Wisconsin, United States

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Publications (133)465.23 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Further to our previous reports on the isolation of (9βH)-pimaranes, (9βH)-17-norpimaranes, and 17-norpimaranes from the tubers of the African medicinal plant Icacina trichantha,1 – 2 eight additional diterpenoids (1 – 8) were identified. Noteworthily, 8 is a 17,19-dinorpimarane. We propose diterpenoids in Icacina plants are biosynthesized from (9βH)-pimarane rather than pimarane. All isolates were evaluated for cytotoxic activity against MDA-MB-435, MDA-MB-231, and OVCAR3 cell lines, with humirianthenolide C being most active (IC50 of 0.7 µM).
    American Society of Pharmacognosy (ASP), Copper Mountain, Colorado, United States of America.; 07/2015
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    ABSTRACT: Eight new and 10 known compounds were isolated from an organic extract of the bulbs of Bellevalia eigii as part of a search for anticancer leads from native plants of Jordan. Of these, the series of 16 homoisoflavonoids (1-16) comprise the seven new analogues 7-O-methyl-3'-hydroxy-3,9-dihydropunctatin (3), 6-hydroxy-7-O-methyl-3,9-dihydropunctatin (6), 7,4'-di-O-methyl-3'-hydroxy-3,9-dihydropunctatin (9), 7-O-methylpunctatin (10), 7-O-methyl-3'-hydroxypunctatin (13), 5-hydroxy-7,8-dimethoxychroman-4-one (14), and 7-O-methyl-8-demethoxy-3-hydroxy-3,9-dihydropunctatin (15). The known ferulic acid-derived acrylamide (17) and the new methylthioacrylate bellegimycin (18) are also reported. The structures were elucidated using a set of spectroscopic and spectrometric techniques; the absolute configurations of compounds 1-9, 15, and 16 were determined using ECD spectroscopy, while a modified Mosher's ester method was used for compound 18. Optical rotation data for the known compounds 1, 2, and 8 are reported here for the first time. The cytotoxic activities of all compounds were evaluated using the MDA-MB-435 (melanoma) and HT-29 (colon) cancer cell lines. Compounds 4 and 9 were the most potent on the latter cell line, with IC50 values of 1.0 and 1.1 μM, respectively. Compounds 1-18 were assessed for antimicrobial activity using a collection of bacteria and fungi; compounds 4 and 12 showed promising activity against the bacterium Mycobacterium smegmatis with MIC values of 17 and 24 μg/mL, respectively.
    Journal of Natural Products 07/2015; 78(7). DOI:10.1021/acs.jnatprod.5b00357 · 3.95 Impact Factor
  • Magnetic Resonance in Chemistry 06/2015; DOI:10.1002/mrc.4254 · 1.56 Impact Factor
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    ABSTRACT: Extract from the cultured freshwater cf. Oscillatoria sp. UIC 10045 showed antiproliferative activity against HT-29 cell line. Bioassay-guided fractionation led to the isolation of two new cyclic lipopeptides, named trichormamides C (1) and D (2). The planar structures were determined by combined analyses of HRESIMS, Q-TOF ESIMS/MS, and 1D and 2D NMR spectra. The absolute configurations of the amino acid residues were assigned by advanced Marfey's analysis after partial and complete acid hydrolysis. Trichormamides C (1) is a cyclic undecapeptide and D (2) is a cyclic dodecapeptide, both containing a lipophilic β-aminodecanoic acid residue. Trichormamide C (1) displayed antiproliferative activities against HT-29 and MDA-MB-435 cancer cell lines with IC50 values of 1.7 and 1.0μM, respectively, as well as anti-Mycobacterium tuberculosis activity with MIC value of 23.8μg/mL (17.3μM). Trichormamide D (2) was found to be less potent against both HT-29 and MDA-MB-435 cancer cell lines with IC50 values of 11.5 and 11.7μM, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Bioorganic & medicinal chemistry 05/2015; 23(13). DOI:10.1016/j.bmc.2015.04.073 · 2.95 Impact Factor
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    ABSTRACT: Seven new 17-norpimarane and (9βH)-17-norpimarane diterpenoids, icacinlactones A-G (1-7), were isolated from the tuber of Icacina trichantha. The structures were elucidated by spectroscopic and HRMS techniques, and the absolute configuration of 2 was determined by means of X-ray crystallographic analysis. Compounds 1-7, as well as four known related structures, were evaluated for cytotoxic activity against MDA-MB-435 (human melanoma cancer), MDA-MB-231 (human breast cancer), and OVCAR3 (human ovarian cancer) cell lines. Several of these natural products displayed significant cytotoxic activity, with humirianthenolide C being the most active.
    Journal of Natural Products 03/2015; 78(4). DOI:10.1021/np5010328 · 3.95 Impact Factor
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    ABSTRACT: Sixteen polyketides belonging to diverse structural classes, including monomeric/dimeric tetrahydroxanthones and resorcylic acid lactones, were isolated from an organic extract of a fungal culture Setophoma terrestris (MSX45109) by bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi. Of these, six were new: penicillixanthone B (5), blennolide H (6), 11-deoxyblennolide D (7), blennolide I (9), blennolide J (10), and pyrenomycin (16). The known compounds were: secalonic acid A (1), secalonic acid E (2), secalonic acid G (3), penicillixanthone A (4), paecilin B (8), aigialomycin A (11), hypothemycin (12), dihydrohypothemycin (13), pyrenochaetic acid C (14), and nidulalin B (15). The structures were elucidated by a set of spectroscopic and spectrometric techniques: the absolute configurations of compounds 1–10 were determined by ECD spectroscopy combined with time-dependent density functional theory (TDDFT) calculations, whereas a modified Mosher's ester method was used for compound 16. The cytotoxic activities of compounds 1–15 against the MDA-MB-435 (melanoma) and SW-620 (colon) cancer cell lines were evaluated. Compounds 1, 4, and 12 were the most potent, with IC50 values ranging from 0.16 to 2.14 μM. When tested against a panel of bacteria and fungi, compounds 3 and 5 showed promising activity against the Gram-positive bacterium Micrococcus luteus, with MIC values of 5 and 15 μg mL–1, respectively.
    European Journal of Organic Chemistry 01/2015; 2015(1). DOI:10.1002/ejoc.201402984 · 3.15 Impact Factor
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    ABSTRACT: Three (9βH)-pimaranes, 1, 2, and 3, and two (9βH)-17-norpimaranes, 4 and 5, belonging to a rare compound class in nature, were obtained from the tubers of Icacina trichantha for the first time. Compound 1 is a new natural product, and 2-5 have been previously reported. The structures were elucidated based on NMR and MS data, and optical rotation values. The absolute configurations of (9βH)-pimaranes were unambiguously established based on X-ray crystallographic analysis. Full NMR signal assignments for the known compounds 2, 4, and 5, which were not available in previous publications, are also reported. All five isolates displayed cytotoxic activities on MDA-MB-435 cells (IC50 0.66-6.44 μM), while 2, 3, and 4 also exhibited cytotoxicities on HT-29 cells (IC50 3.00-4.94 μM). Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.
    Chemistry & Biodiversity 12/2014; 11(12):1914-22. DOI:10.1002/cbdv.201400151 · 1.80 Impact Factor
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    ABSTRACT: Higher plants continue to afford humankind with many new drugs, for a variety of disease types. In this review, recent phytochemical and biological progress is presented for part of a collaborative multi-institutional project directed towards the discovery of new antitumor agents. The specific focus is on bioactive natural products isolated and characterized structurally from tropical plants collected in Vietnam. The plant collection, identification, and processing steps are described, and the natural products isolated from these species are summarized with their biological activities.
    Phytochemistry Reviews 12/2014; 13(4). DOI:10.1007/s11101-014-9335-7 · 2.89 Impact Factor
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    ABSTRACT: Semaphorins are a class of membrane-bound and secreted proteins. They have been found to regulate basic cell functions such as axonal growth cone guidance and recent studies have focused on their effect on tumor progression. Semaphorin 3B (Sema3B) particularly is a secreted protein that has been known to modulate proliferation and apoptosis, processes that are critical for tumor progression and development. In spite of its importance, there is yet no high-throughput screening assay available to detect or quantify the expression of Sema3B for natural product cancer drug discovery purposes. Therefore, the development of a new high-throughput bioassay for the discovery of Sema3B inducing agents from natural product sources is described herein. A wide variety of pure compounds and extracts from plants and microorganisms have been found suitable for screening using this Sema3B assay to detect and quantify the effect of Sema3B inducing agents and thereby identify new selective bioactive Sema3B lead compounds for cancer drug discovery and development. Also, this new bioassay procedure is based on a high-throughput platform using an enzyme-linked immunosorbent assay that involves the optimization of sensitivity and selectivity levels as well as accuracy, reproducibility, robustness, and cost effectiveness.
    Fitoterapia 10/2014; 98(8 Supplement). DOI:10.1016/j.fitote.2014.07.004 · 2.22 Impact Factor
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    ABSTRACT: As part of an ongoing project to explore filamentous fungi for anticancer and antibiotic leads, 11 compounds were isolated and identified from an organic extract of the fungus Scytalidium album (MSX51631) using bioactivity-directed fractionation against human cancer cell lines. Of these, eight compounds were a series of sorbicillinoid analogs (1-8), of which four were new (scalbucillin A (2), scalbucillin B (3), scalbucillin C (6) and scalbucillin D (8)), two were phthalides (9-10) and one was naphthalenone (11). Compounds (1-11) were tested in the MDA-MB-435 (melanoma) and SW-620 (colon) cancer cell lines. Compound 1 was the most potent with IC50 values of 1.5 and 0.5 μM, followed by compound 5 with IC50 values of 2.3 and 2.5 μM at 72 h. Compound 1 showed a 48-h IC50 value of 3.1 μM when tested against the lymphocytic leukemia cell line OSU-CLL, while the nearly identical compound 5 had almost no activity in this assay. Compounds 1 and 5 showed selective and equipotent activity against Aspergillus niger with minimum IC values of 0.05 and 0.04 μg ml(-1) (0.20 and 0.16 μM), respectively. The in vitro hemolytic activity against sheep erythrocytes of compounds 1 and 5 was investigated and were found to provoke 10% hemolysis at 52.5 and 45.0 μg ml(-1), respectively, indicative of a promising safety factor.The Journal of Antibiotics advance online publication, 24 September 2014; doi:10.1038/ja.2014.125.
    The Journal of Antibiotics 09/2014; 68(3). DOI:10.1038/ja.2014.125 · 2.04 Impact Factor
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    ABSTRACT: Seven withanolides were isolated from the leaves of Withania obtusifolia. Of these, one was new [obtusifonolide (1)], five were new to the species [sitoindoside IX (2), 6 alpha-chloro-5 beta-hydroxy withaferin A (3), isowithanone (4), 2,3-dihydro-3-ethoxywithaferin A (5), and daturataturin A (6)], and one was reported previously from W. obtusifolia [withaferin A (7)]. The structures were elucidated using a set of spectroscopic and spectrometric techniques. Compounds (1-7) were evaluated for cytotoxicity against a human cancer cell panel and for antimicrobial activity in an array of bacteria and fungi. Compound 7 showed cytotoxic activity against the MDA-MB-435 (human melanoma) and SW-620 (human colon cancer) cell lines with IC50 values of 1.7 and 0.3 mu M, respectively. The in vitro activity of 7 on 17 beta-hydroxysteroid dehydrogenase and 5 alpha-reductase was also investigated.
    Phytochemistry Letters 09/2014; 9. DOI:10.1016/j.phytol.2014.05.002 · 1.54 Impact Factor
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    ABSTRACT: Fourteen new resorcylic acid lactones (1-14) were isolated from an organic extract of a culture of a freshwater aquatic fungus Halenospora sp. originating from a stream in North Carolina. The structures were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configuration of one representative member of the compounds (7) was assigned using X-ray crystallography of an analogue that incorporated a heavy atom, whereas for compounds 8-11, a modified Mosher's ester method was utilized. The relative configurations of compounds 12-14 were determined on the basis of NOE data. Compounds 12-14 were proposed as artifacts produced by intramolecular cycloetherification of the ε-hydroxy-α,β-unsaturated ketone moieties of the parent compounds during the purification processes. The isolated compounds, except for 8 and 12, were tested against the MDA-MB-435 (melanoma) and HT-29 (colon) cancer cell lines. Compound 5 was the most potent, with IC50 values of 2.9 and 7.5 μM, respectively. The compounds were evaluated as TAK1-TAB1 inhibitors but were found to be inactive.
    Journal of Natural Products 08/2014; 77(9). DOI:10.1021/np500497r · 3.95 Impact Factor
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    ABSTRACT: Two new cyclic lipopeptides, trichormamides A (1) and B (2), were isolated from the cultured freshwater cyanobacterium Trichormus sp. UIC 10339. The strain was obtained from a sample collected in Raven Lake in Northern Wisconsin. The planar structures of trichormamides A (1) and B (2) were determined using a combination of spectroscopic analyses including HRESIMS and 1D and 2D NMR experiments. The absolute configurations of the amino acid residues were assigned by the advanced Marfey's method after acid hydrolysis. Trichormamide A (1) is a cyclic undecapeptide containing two d-amino acid residues (d-Tyr and d-Leu) and one β-amino acid residue (β-aminodecanoic acid). Trichormamide B (2) is a cyclic dodecapeptide characterized by the presence of four nonstandard α-amino acid residues (homoserine, N-methylisoleucine, and two 3-hydroxyleucines) and one β-amino acid residue (β-aminodecanoic acid). Trichormamide B (2) was cytotoxic against MDA-MB-435 and HT-29 cancer cell lines with IC50 values of 0.8 and 1.5 μM, respectively.
    Journal of Natural Products 08/2014; 77(8). DOI:10.1021/np5003548 · 3.95 Impact Factor
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    ABSTRACT: GH and/or IGF-I are thought to promote breast cancer based on reports showing circulating IGF-I levels correlate, in epidemiological studies, with breast cancer risk. Also, mouse models with developmental GH/IGF-I deficiency/resistance are less susceptible to genetic- or chemical-induced mammary tumorigenesis. However, given the metabolic properties of GH, medical strategies have been considered to raise GH to improve body composition and metabolic function in elderly and obese patients. Since hyperlipidemia, inflammation, insulin resistance and obesity increase breast cancer risk, elevating GH may serve to exacerbate cancer progression. To better understand the role GH/IGF-I plays in tumor formation, this study used unique mouse models to determine if reducing GH/IGF-I in adults protects against DMBA-induced mammary tumor development, and if moderate elevations in endogenous GH/IGF-I alter DMBA-induced tumorigenesis in mice fed a standard-chow diet or in mice with altered metabolic function due to high-fat feeding. We observed that adult-onset isolated GH deficient (AOiGHD) mice, which also have reduced IGF-I levels, were less susceptible to DMBA-treatment. Specifically, fewer AOiGHD mice developed mammary tumors compared to GH-replete controls. In contrast, chow-fed mice with elevated endogenous GH/IGF-I (HiGH mice) were not more susceptible to DMBA-treatment. However, high-fat-fed, HiGH mice showed reduced tumor latency and increased tumor incidence compared to diet-matched controls. These results further support a role of GH/IGF-I in regulating mammary tumorigenesis but suggest the ultimate consequences of GH/IGF-I on breast tumor development are dependent on the diet and/or metabolic status.
    Carcinogenesis 08/2014; 35(11). DOI:10.1093/carcin/bgu161 · 5.27 Impact Factor
  • A Kaur · SM Swanson · CJ Pearce · NH Oberlies
    Planta Medica 07/2014; 80(10). DOI:10.1055/s-0034-1382416 · 2.34 Impact Factor
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    MM Onakpa · M Zhao · T Gödecke · WL Chen · SM Swanson · AI Uzoma · CT Che
    Planta Medica 07/2014; 80(10). DOI:10.1055/s-0034-1382530 · 2.34 Impact Factor
  • Planta Medica 07/2014; 80(10). DOI:10.1055/s-0034-1382475 · 2.34 Impact Factor
  • WL Chen · SM Swanson
    Planta Medica 07/2014; 80(10). DOI:10.1055/s-0034-1382590 · 2.34 Impact Factor
  • JR Fuchs · JL Woodard · Y Ren · HB Chai · JC Yalowich · J Yu · SM Swanson · AD Kinghorn
    Planta Medica 07/2014; 80(10). DOI:10.1055/s-0034-1382582 · 2.34 Impact Factor
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    ABSTRACT: Abstract Two new (1 and 2) and three known (3–5) carbamidocyclophanes were isolated from a cultured freshwater cyanobacterium Nostoc sp. (UIC 10274) obtained from a sample collected at Des Plaines, Illinois. Their planar structures and stereoconfigurations were determined by extensive spectroscopic analysis including 1D/2D NMR experiments, HRESIMS as well as CD spectroscopy. Carbamidocyclophane F (1) showed potent anti-Mycobacterium tuberculosis activity in the microplate Alamar blue assay and low-oxygen-recovery assay with MIC values of 0.8 and 5.4 μM, respectively. Carbamidocyclophane F (1) also displayed antimicrobial activities against the gram positive bacteria Staphylococcus aureus and Enterococcus faecalis with MIC values of 0.1 and 0.2 μM, respectively. Carbamidocyclophane F (1) and Carbamidocyclophane G (2) both showed antiproliferative activity against MDA-MB-435 and HT-29 human cancer cell lines with IC50 values in the range from 0.5 to 0.7 μM.
    Tetrahedron Letters 07/2014; 55:686 - 689. DOI:10.1016/j.tetlet.2013.11.112 · 2.39 Impact Factor

Publication Stats

2k Citations
465.23 Total Impact Points

Institutions

  • 2015
    • University of Wisconsin–Madison
      Madison, Wisconsin, United States
  • 1986–2015
    • University of Illinois at Chicago
      • • Department of Medicinal Chemistry and Pharmacognosy
      • • Department of Surgical Oncology (Chicago)
      • • College of Pharmacy
      Chicago, Illinois, United States
  • 2013
    • Columbus State University
      Columbus, Georgia, United States
  • 2006–2013
    • The Ohio State University
      • Division of Medicinal Chemistry and Pharmacognosy
      Columbus, Ohio, United States
  • 1992–1999
    • University of California, Berkeley
      • Department of Molecular and Cell Biology
      Berkeley, MO, United States