Corey Levenson - Academia.edu (original) (raw)
Papers by Corey Levenson
Nucleic Acids Research, 1991
A convenient format for the detection of PCR amplified sequences is the hybridization of the PCR ... more A convenient format for the detection of PCR amplified sequences is the hybridization of the PCR products to oligonucleotide probes which are immobilized on a solid phase. We describe a new method for site-specific attachment of such probe oligonucleotides to nylon membranes. The method is based on the formation of an amide bond between carboxyl groups present on the membranes and amino-linkers situated on the 5' end of the oligonucleotides. The covalent attachment is via a carbodilmide mediated condensation. The single, 5' end attachment of the oligonucleotides to the membrane surface leaves the probe free to interact with complementary sequences, thus increasing the hybridization efficiency relative to methods where heat or ultraviolet light is used for non-specific fixation. Using biotinylated PCR products in hybridization reactions along with a non-radioactive chemiluminescent detection system, high efficiency hybridization is obtained as well as a very good signal to noise ratio. The method has been applied successfully to the detection of RAS point mutations, cystic fibrosis deletion and point mutations and others. The sensitivity, simplicity and reproducibility of this method make it an ideal tool for the diagnosis of infectious and genetic diseases, as well as analysis of mutations in neoplasias, HLA typing and other areas.
Elsevier eBooks, 1990
Publisher Summary Nucleic acid hybridization probes are widely used biochemical reagents with app... more Publisher Summary Nucleic acid hybridization probes are widely used biochemical reagents with applications in research and diagnostics. Nonradioactive labels are preferable owing to their ease of handling and disposal and their long shelf life. One of the preferred labels for non-isotopically labeled probes is biotin. Conjugates of various enzymes with avidin or streptavidin are employed for colorimetric detection. Each probe consists of a single-stranded hybridizing region linked to a double-stranded region containing preferred psoralen-binding sites. The psoralen-derived labeling reagents have three domains: the trimethylpsoralen ring system, a long, flexible, hydrophilic spacer arm, and the nonisotopic label. For the reagent, the psoralen ring system is derived from trimethylpsoralen (trioxsalen), the spacer arm is derived from tetraethylene glycol, and the label is biotin. Partially double-stranded probe constructs are biotinylated by mixing the labeling reagent with the probe DNA at a molar ratio of 2:1 and a DNA concentration of 100/μg/ml in 100 mM NaC1, 10 mM Tris (pH 7.5), and 1 mM ethylenediaminetetraacetic acid (EDTA).
ChemInform, Aug 23, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
PubMed, Dec 1, 2012
Background: A proprietary topical blend of salicylic acid and highly purified sandalwood oil from... more Background: A proprietary topical blend of salicylic acid and highly purified sandalwood oil from Australia was used in this open-label study in adolescents and adults with mild to moderate facial acne. Methods: The investigational regimen consisted of a foaming cleanser, an acne serum, a spot treatment, and a mask. Patients applied the treatment regimen as directed for 8 weeks. The primary efficacy measure was the percentage of patients assessed as improved, much improved, or very much improved according to the Global Aesthetic Improvement Scale (GAIS) ratings at week 8. Severity was rated using the Evaluator's Global Severity Scores (EGSS) at baseline and weeks 2, 4, and 8. Tolerability was assessed at baseline and weeks 2, 4, and 8 by asking patients to rate the severity of itching, scaling, erythema, burning, dryness, and stinging. Patients were also asked to complete an acne questionnaire. Results: 89.4% (42/47) met the primary end point determined by the GAIS of improved (66%), much improved (19%), or very much improved (4%). Notable reductions in lesion counts were observed in patients with more severe or inflamed lesions. Tolerability was queried at all visits. No itching, scaling, or erythema was reported after initial application. Symptoms of intolerability peaked at week 2; however, most events were mild to moderate and were typically reported with use of the mask component. Intolerance decreased by week 4 and by week 8. The treatment regimen was well tolerated by patients. Conclusions: Results from this study support the use of a proprietary investigational regimen in patients with mild to moderate acne and warrant further investigation to determine whether longer-term therapy (ie, beyond 8 weeks) results in enhanced efficacy with minimal side effects, leading to continued patient compliance and skin improvement.
Biochemical Pharmacology, Feb 1, 1980
Recent investigations by Sadee and coworkers on the mechanism of activation of the anti-cancer dr... more Recent investigations by Sadee and coworkers on the mechanism of activation of the anti-cancer drug 5-fluoro-1-(tetrabydrofuran-2-yl)-uracil (ftorafur) in rats and rabbits [I] and in humans [2] have shown the existence of some hydroxylated metabolftes. We now report the total stereospecific synthesis of I-(2-deoxy-S-Pglycero-tetrafuranosy~~-5-fluorwur&c~l (I) and 1-(3-deo~-~~-~lyc~r~-tet~ofuranosyl~-5-fluorouracil (II>, their equivalence with the ftorafur metabolites by ehromatographic and spectral comparison, and the absolute configuration of one of the metabelites.
PubMed, Oct 1, 2017
Many skin conditions and diseases are characterized by inflammation, infection, and hyperplasia. ... more Many skin conditions and diseases are characterized by inflammation, infection, and hyperplasia. Safe and effective topical treatment options that can be used long-term are needed. Traditional botanical medicines, which are often complex mixtures that exert their biological activities via multiple mechanisms of action, are being studied as potential new active ingredients in dermatology. Sandalwood album oil (SAO), also known as East Indian sandalwood oil (EISO), is an essential oil distilled from the Santalum album tree and has demonstrated biological activity as an anti-inflammatory, anti-microbial, and anti-proliferative agent. Sandalwood album oil has also shown promise in clinical trials for treatment of acne, psoriasis, eczema, common warts, and molluscum contagiosum. The favorable safety profile, ease of topical use, and recent availability of pharmaceutical-grade sandalwood album oil support its broader use as the basis of novel therapies in dermatology.
RSC Advances, 2018
East Indian Sandalwood Oil (EISO) has diverse beneficial effects and has been used for thousands ... more East Indian Sandalwood Oil (EISO) has diverse beneficial effects and has been used for thousands of years in traditional folk-medicine for treatment of different human ailments. However, there has been no in-depth scientific investigation to decipher the neuroprotective and geroprotective mechanism of EISO and its principle components, aand b-santalol. Hence the current study was undertaken to assess the protective effects of EISO, and aand b-santalol against neurotoxic (6-OHDA/6-hydroxydopamine) and proteotoxic (a-synuclein) stresses in a Caenorhabditis elegans model. Initially, we found that EISO and its principle components exerted an excellent antioxidant and antiapoptotic activity as it was able to extend the lifespan, and inhibit the ROS generation, and germline cell apoptosis in 6-OHDA-intoxicated C. elegans. Further, we showed that supplementation of EISO, and aand b-santalol reduced the 6-OHDA and a-synuclein-induced Parkinson's disease associated pathologies and improved the physiological functions. The genetic and reporter gene expression analysis revealed that an EISO, or aand b-santalolmediated protective effect does not appear to rely on DAF-2/DAF-16, but selectively regulates SKN-1 and its downstream targets involved in antioxidant defense and geroprotective processes. Together, our findings indicated that EISO and its principle components are worth exploring further as a candidate redox-based neuroprotectant for the prevention and management of age-related neurological disorders.
Biochemistry, Jun 25, 1991
We have investigated the structure and physical chemistry of the d(C3T4C3).2[d(G3A4G3)] triple he... more We have investigated the structure and physical chemistry of the d(C3T4C3).2[d(G3A4G3)] triple helix by polyacrylamide gel electrophoresis (PAGE), 1H NMR, and ultraviolet (UV) absorption spectroscopy. The triplex was stabilized with MgCl2 at neutral pH. PAGE studies verify the stoichiometry of the strands comprising the triplex and indicate that the orientation of the third strand in purine-purine-pyrimidine (pur-pur-pyr) triplexes is antiparallel with respect to the purine strand of the underlying duplex. Imino proton NMR spectra provide evidence for the existence of new purine-purine (pur.pur) hydrogen bonds, in addition to those of the Watson-Crick (W-C) base pairs, in the triplex structure. These new hydrogen bonds are likely to correspond to the interaction between third-strand guanine NH1 imino protons and the N7 atoms of guanine residues on the purine strand of the underlying duplex. Thermal denaturation of the triplex proceeds to single strands in one step, under the conditions used in this study. Binding of the third strand appears to enhance the thermal stability of the duplex by 1-3 degrees C, depending on the DNA concentration. The free energy of triplex formation (-26.0 +/- 0.5 kcal/mol) is approximately twice that of duplex formation (-12.6 +/- 0.7 kcal/mol), suggesting that the overall stability of the pur.pur base pairs is similar to that of the W-C base pairs.(ABSTRACT TRUNCATED AT 250 WORDS)
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), May 1, 1986
Structural determinations of oligonucleotides and their complexes using distance measurements bas... more Structural determinations of oligonucleotides and their complexes using distance measurements based on NOE data are limited due to the relatively short distances available from this technique (less than or equal to 5 A). Extension of NMR measurements to longer distances would greatly augment the information currently obtainable. Effects over a range of approx.20 A can be observed by the incorporation of a paramagnetic spin label at a unique site into an oligomer by establishing a linewidth gradient with an r/sup -6/ dependence on the electron-proton distance. They have therefore synthesized a nonpalindromic oligonucleotide duplex with the sequence /sup 5'/CCACGG./sup 5'/CCGTGG as well as the two corresponding oligonucleotides containing 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (TEMPO) attached by a phosphodiester linkage to the 5'terminus. The /sup 1/H NMR spectra obtained at 500 MHz of the spin-labeled duplexes have been analyzed and the resonances assigned. The extent of line broadening for the nucleotide resonances of the labeled duplexes has been measured and correlated to the distance between the label and the average proton position based on the crystal structure of B-DNA. This study suggests that it is feasible to acquire information over longer distances for the determination of solution structures of oligonucleotides and oligonucleotide:ligand complexes by distancemore » geometry algorithms.« less
α-Santalol, one of the primary components of the East Indian sandalwood oil (EISO), has been inve... more α-Santalol, one of the primary components of the East Indian sandalwood oil (EISO), has been investigated for its potential use as a chemopreventive agent in skin cancer. Although there is some evidence that α-santalol could be an effective chemopreventive agent, to date, purified EISO has not been investigated. EISO is widely used for its health benefits in cultures around the world. In the current study, we show for the first time that EISO-treatment of cultured keratinocytes inhibits cell cycle progression and UV-induced AP-1 activity, two major cellular effects known to drive skin carcinogenesis. Unlike many chemopreventive agents, inhibition of signaling upstream of AP-1 was not a primary means of EISO-mediated AP-1 inhibition, as no effect of EISO was observed on UV-induced Akt, ERK, and p38 MAPK activity. EISO induced cell death at low concentrations, although caspase and PARP cleavage were not observed indicating that death was not due to apoptosis. Interestingly, plasma membrane integrity was severely compromised in EISO-treated cells and LC3 cleavage suggests the induction of autophagy. These effects were more pronounced in EISO-treated cells that were stimulated to proliferate than in quiescent cells. Together, these effects suggest that EISO has chemopreventive properties and may be useful as in preventing skin carcinogenesis. Citation Format: Corey Levenson, Erik R. Olson, David S. Alberts, G. Tim Bowden. A novel chemopreventive mechanism for a traditional medicine: East Indian sandalwood oil induces autophagy and cell death in proliferating keratinocytes. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2254. doi:10.1158/1538-7445.AM2013-2254
Journal of Natural Products, May 20, 2015
Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, with no ... more Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, with no major advancements in treatment over the past 40 years. The current study explores the biological effects of East Indian sandalwood oil (EISO) and its two major constituents, αand β-santalol, against a variety of HNSCC lines. All three agents exhibited cytotoxic effects and caused accumulation of cells in the G2/M phases of the cell cycle. Additionally, treatment with these agents caused formation of multipolar mitotic spindles similar to those observed upon treatment of cells with compounds that affect microtubule polymerization. Indeed, the santalols, as well as EISO, inhibited the polymerization of purified tubulin, indicating for the first time that these compounds have the ability to directly bind to tubulin and affect microtubule formation. Modeling studies suggest that the santalols can weakly bind to the colchicine site on tubulin, and topical administration of EISO to a HNSCC xenograft inhibited tumor growth with no observed toxicities. Therefore, santalols can directly interact with tubulin to inhibit the polymerization of microtubules, similarly to established classes of chemotherapeutic agents, albeit with greatly reduced potency that is not associated with the classic toxicity associated with most other compounds that interact directly with tubulin.
Journal of Medicinal Chemistry, Feb 1, 1984
Three new heterocyclic analogues (4-6) of dihydroorotic acid were designed, synthesized, and test... more Three new heterocyclic analogues (4-6) of dihydroorotic acid were designed, synthesized, and tested as inhibitors of dihydroorotase. Each compound possessed a tetrahedral sulfur atom at the position equivalent to carbon 4 in the dihydroorotate ring in an attempt to mimic the presumed tetrahedral transition state in the course of the enzymatic reaction. Additionally, N-carbamyl-3-phosphonoalanine was prepared and evaluated as a dihydroorotase inhibitor. Compounds 4 and 6 were modest inhibitors (Zm's of 0.52 and 0.18 mM, respectively), but the other candidate inhibitors showed little inhibition at 1 mM. Dihydroorotase (EC 3.5.2.3) catalyzes the cyclization of N-carbamylaspartate (1) to dihydroorotate (2), the third Scheme I r-0, +>+OH 12
Journal of Biological Chemistry, Mar 1, 1995
Journal of Medicinal Chemistry, Aug 1, 1988
Reaction of the trimethylsilylated derivative of 1,4-thiazin-3-one with l-O-acetyl-2,3,5-triO -be... more Reaction of the trimethylsilylated derivative of 1,4-thiazin-3-one with l-O-acetyl-2,3,5-triO -benzoyl-~-ribofuranose in the presence of SnC4 gave, after deblocking, 4-P-~-ribofuranosyl-1,4-thiazin-3-one (8). Treatment of 1,4-thiazin-3-one with l-chloro-2-deoxy-3,5-di-O-p-toluoyl-cu-~-erythro-pentofuranose in the presence of sodium hydride provided, after deblocking, the corresponding 2-deoxy-/3-~-ribofuranosyl derivatives (19). Oxidation of 4-(2,3,5-tri-Obenzoyl-~-~-ribofuranosyl)-l,4-thiazin-3-one (7) with 1 equiv of m-chloroperbenzoic acid resulted in 4-(2,3,5-tri-Obenzoyl-~-~-ribofuranosyl)-1,4-thiazine-2,3-dione (9) and 4-(2,3,5-tri-0-benzoyl-~-~-ribofuranosyl)-l,4-thiazin-3-one 1-oxide (10). Evidence is presented that indicates that the oxidation of the thiazine at the 2-position is due to a Pummerer rearrangement. The new compounds failed to show significant activity against tumor cell lines in culture, L1210 cells in vivo, virus cytotoxicity in cell culture, or cytidine deaminase.
Journal of Biomolecular Structure & Dynamics, Apr 1, 1987
The nonexchangeable base and sugar protons of the octanucleotide d(ACCCGGGT)2 have been assigned ... more The nonexchangeable base and sugar protons of the octanucleotide d(ACCCGGGT)2 have been assigned using two dimensional homonuclear Hartmann-Hahn relayed spectroscopy (HOHAHA), double quantum filtered homonuclear correlation spectroscopy (DQFCOSY) and nuclear Overhauser spectroscopy (NOESY) in D2O at 12 degrees C. The observed NOE's between the base protons and their own H2' protons and between the base protons and the H2' protons of the 5' adjacent nucleotide and the observed coupling constants between the deoxyribose 1' and 2',2'' protons indicate that this duplex assumes a right-handed B-type helix conformation in solution.
Elsevier eBooks, 1987
Publisher Summary The development of oligonucleotide-directed site-specific mutagenesis on single... more Publisher Summary The development of oligonucleotide-directed site-specific mutagenesis on single-stranded phage template has provided a powerful new technique in the study of structure-function relationships of proteins. This chapter describes a simplified procedure for oligonucleotide-directed site-specific mutagenesis on M13 single-stranded phage deoxyribo nucleic acid (DNA) templates. The rationale behind this approach is to make use of the DNA repair mechanism present in the E. coli host to repair the gapped M13 phage DNA into the covalently closed circular form before replication of the DNA molecules. The mutagenesis procedure described in this chapter provides a rapid method for the modification of cloned genes. It takes advantage of the ability of E. coli to efficiently repair gapped circular DNA molecules, to shorten the overall time of the mutagenesis, from initiation of the mutagenesis reaction to the identification of the mutant phage plaque. Although this faster method is less efficient in the conversion of parent DNA to mutant DNA molecules, the ability to use the same oligonucleotide primer as a probe to identify the mutant phage plaques effectively compensates for this inefficiency.
Nature Biotechnology, Mar 1, 1989
Industrial Crops and Products, Nov 1, 2019
The East Indian sandalwood oil has been widely used as an Ayurvedic medicine and has multiple pha... more The East Indian sandalwood oil has been widely used as an Ayurvedic medicine and has multiple pharmacological properties. However, antioxidant and antistress potency of East Indian sandalwood oil against oxidative stress-induced damages remain unexplored. Thus, the present study was aimed to investigate the in vitro and in vivo antioxidant and stress-protective properties of essential oil extracted from the heartwood of plantationgrown Santalum album L. (SEO). The SEO was extracted by traditional stream distillation method and the chemical components were determined via gas chromatography-mass spectrometry (GC-MS) analysis. Nineteen chemical compounds were identified by GC-MS, accounting for 96.81% of total oil. The main components were α-santalol (41.77%), β-santalol (18.02%), (Z)-α-trans-bergamotol (8.50%), (Z)-lanceol (6.57%), and epi-β-santalol (5.78%). The in vitro results suggests that SEO possess an excellent antioxidant activity as it was able to inhibits the intracellular reactive oxygen species (ROS) generation, reverse the morphological damages and effectively improves viability of neural cells under oxidative stress conditions. Moreover, SEO markedly increased the antioxidant enzyme activities of superoxide dismutase, catalase, and glutathione peroxidase. Western blotting results further confirmed that SEO protects neural cells against oxidative damages possibly by activating the nuclear factor-erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) antioxidant mechanism. The SEO also exhibited a strong in vivo antioxidant and stress modulatory activity on Caenorhabditis elegans. The SEO not only acts protective against oxidative stress but also prolongs the lifespan of mev-1 mutant C. elegans having shortened lifespan due to the over production of ROS. This data confirmed that SEO exert potent antioxidant and stress modulatory activities possibly by direct scavenging of free radicals and activation of antioxidant defense system, in vitro and in vivo. Together, these findings indicated that SEO has the potency to be utilized as a source of antioxidant for treating several degenerative and disease conditions caused by oxidative stress.
The New England Journal of Medicine, Sep 1, 1988
We have developed a simple and rapid nonradioactive method for detecting genetic variation and ha... more We have developed a simple and rapid nonradioactive method for detecting genetic variation and have applied it to the diagnosis of sickle cell anemia and beta-thalassemia. The procedure involves the selective amplification of a segment of the human beta-globin gene with oligonucleotide primers and a thermostable DNA polymerase, followed by hybridization of the amplified DNA with allele-specific oligonucleotide probes covalently labeled with horseradish peroxidase. The hybridized probes were detected with a simple colorimetric assay. We demonstrated the usefulness of this method in a retrospective analysis of two pregnancies at risk for beta-thalassemia and one at risk for sickle cell anemia, as well as in an analysis of nine DNA samples simulating three family sets.
Nucleic Acids Research, 1991
A convenient format for the detection of PCR amplified sequences is the hybridization of the PCR ... more A convenient format for the detection of PCR amplified sequences is the hybridization of the PCR products to oligonucleotide probes which are immobilized on a solid phase. We describe a new method for site-specific attachment of such probe oligonucleotides to nylon membranes. The method is based on the formation of an amide bond between carboxyl groups present on the membranes and amino-linkers situated on the 5' end of the oligonucleotides. The covalent attachment is via a carbodilmide mediated condensation. The single, 5' end attachment of the oligonucleotides to the membrane surface leaves the probe free to interact with complementary sequences, thus increasing the hybridization efficiency relative to methods where heat or ultraviolet light is used for non-specific fixation. Using biotinylated PCR products in hybridization reactions along with a non-radioactive chemiluminescent detection system, high efficiency hybridization is obtained as well as a very good signal to noise ratio. The method has been applied successfully to the detection of RAS point mutations, cystic fibrosis deletion and point mutations and others. The sensitivity, simplicity and reproducibility of this method make it an ideal tool for the diagnosis of infectious and genetic diseases, as well as analysis of mutations in neoplasias, HLA typing and other areas.
Elsevier eBooks, 1990
Publisher Summary Nucleic acid hybridization probes are widely used biochemical reagents with app... more Publisher Summary Nucleic acid hybridization probes are widely used biochemical reagents with applications in research and diagnostics. Nonradioactive labels are preferable owing to their ease of handling and disposal and their long shelf life. One of the preferred labels for non-isotopically labeled probes is biotin. Conjugates of various enzymes with avidin or streptavidin are employed for colorimetric detection. Each probe consists of a single-stranded hybridizing region linked to a double-stranded region containing preferred psoralen-binding sites. The psoralen-derived labeling reagents have three domains: the trimethylpsoralen ring system, a long, flexible, hydrophilic spacer arm, and the nonisotopic label. For the reagent, the psoralen ring system is derived from trimethylpsoralen (trioxsalen), the spacer arm is derived from tetraethylene glycol, and the label is biotin. Partially double-stranded probe constructs are biotinylated by mixing the labeling reagent with the probe DNA at a molar ratio of 2:1 and a DNA concentration of 100/μg/ml in 100 mM NaC1, 10 mM Tris (pH 7.5), and 1 mM ethylenediaminetetraacetic acid (EDTA).
ChemInform, Aug 23, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
PubMed, Dec 1, 2012
Background: A proprietary topical blend of salicylic acid and highly purified sandalwood oil from... more Background: A proprietary topical blend of salicylic acid and highly purified sandalwood oil from Australia was used in this open-label study in adolescents and adults with mild to moderate facial acne. Methods: The investigational regimen consisted of a foaming cleanser, an acne serum, a spot treatment, and a mask. Patients applied the treatment regimen as directed for 8 weeks. The primary efficacy measure was the percentage of patients assessed as improved, much improved, or very much improved according to the Global Aesthetic Improvement Scale (GAIS) ratings at week 8. Severity was rated using the Evaluator's Global Severity Scores (EGSS) at baseline and weeks 2, 4, and 8. Tolerability was assessed at baseline and weeks 2, 4, and 8 by asking patients to rate the severity of itching, scaling, erythema, burning, dryness, and stinging. Patients were also asked to complete an acne questionnaire. Results: 89.4% (42/47) met the primary end point determined by the GAIS of improved (66%), much improved (19%), or very much improved (4%). Notable reductions in lesion counts were observed in patients with more severe or inflamed lesions. Tolerability was queried at all visits. No itching, scaling, or erythema was reported after initial application. Symptoms of intolerability peaked at week 2; however, most events were mild to moderate and were typically reported with use of the mask component. Intolerance decreased by week 4 and by week 8. The treatment regimen was well tolerated by patients. Conclusions: Results from this study support the use of a proprietary investigational regimen in patients with mild to moderate acne and warrant further investigation to determine whether longer-term therapy (ie, beyond 8 weeks) results in enhanced efficacy with minimal side effects, leading to continued patient compliance and skin improvement.
Biochemical Pharmacology, Feb 1, 1980
Recent investigations by Sadee and coworkers on the mechanism of activation of the anti-cancer dr... more Recent investigations by Sadee and coworkers on the mechanism of activation of the anti-cancer drug 5-fluoro-1-(tetrabydrofuran-2-yl)-uracil (ftorafur) in rats and rabbits [I] and in humans [2] have shown the existence of some hydroxylated metabolftes. We now report the total stereospecific synthesis of I-(2-deoxy-S-Pglycero-tetrafuranosy~~-5-fluorwur&c~l (I) and 1-(3-deo~-~~-~lyc~r~-tet~ofuranosyl~-5-fluorouracil (II>, their equivalence with the ftorafur metabolites by ehromatographic and spectral comparison, and the absolute configuration of one of the metabelites.
PubMed, Oct 1, 2017
Many skin conditions and diseases are characterized by inflammation, infection, and hyperplasia. ... more Many skin conditions and diseases are characterized by inflammation, infection, and hyperplasia. Safe and effective topical treatment options that can be used long-term are needed. Traditional botanical medicines, which are often complex mixtures that exert their biological activities via multiple mechanisms of action, are being studied as potential new active ingredients in dermatology. Sandalwood album oil (SAO), also known as East Indian sandalwood oil (EISO), is an essential oil distilled from the Santalum album tree and has demonstrated biological activity as an anti-inflammatory, anti-microbial, and anti-proliferative agent. Sandalwood album oil has also shown promise in clinical trials for treatment of acne, psoriasis, eczema, common warts, and molluscum contagiosum. The favorable safety profile, ease of topical use, and recent availability of pharmaceutical-grade sandalwood album oil support its broader use as the basis of novel therapies in dermatology.
RSC Advances, 2018
East Indian Sandalwood Oil (EISO) has diverse beneficial effects and has been used for thousands ... more East Indian Sandalwood Oil (EISO) has diverse beneficial effects and has been used for thousands of years in traditional folk-medicine for treatment of different human ailments. However, there has been no in-depth scientific investigation to decipher the neuroprotective and geroprotective mechanism of EISO and its principle components, aand b-santalol. Hence the current study was undertaken to assess the protective effects of EISO, and aand b-santalol against neurotoxic (6-OHDA/6-hydroxydopamine) and proteotoxic (a-synuclein) stresses in a Caenorhabditis elegans model. Initially, we found that EISO and its principle components exerted an excellent antioxidant and antiapoptotic activity as it was able to extend the lifespan, and inhibit the ROS generation, and germline cell apoptosis in 6-OHDA-intoxicated C. elegans. Further, we showed that supplementation of EISO, and aand b-santalol reduced the 6-OHDA and a-synuclein-induced Parkinson's disease associated pathologies and improved the physiological functions. The genetic and reporter gene expression analysis revealed that an EISO, or aand b-santalolmediated protective effect does not appear to rely on DAF-2/DAF-16, but selectively regulates SKN-1 and its downstream targets involved in antioxidant defense and geroprotective processes. Together, our findings indicated that EISO and its principle components are worth exploring further as a candidate redox-based neuroprotectant for the prevention and management of age-related neurological disorders.
Biochemistry, Jun 25, 1991
We have investigated the structure and physical chemistry of the d(C3T4C3).2[d(G3A4G3)] triple he... more We have investigated the structure and physical chemistry of the d(C3T4C3).2[d(G3A4G3)] triple helix by polyacrylamide gel electrophoresis (PAGE), 1H NMR, and ultraviolet (UV) absorption spectroscopy. The triplex was stabilized with MgCl2 at neutral pH. PAGE studies verify the stoichiometry of the strands comprising the triplex and indicate that the orientation of the third strand in purine-purine-pyrimidine (pur-pur-pyr) triplexes is antiparallel with respect to the purine strand of the underlying duplex. Imino proton NMR spectra provide evidence for the existence of new purine-purine (pur.pur) hydrogen bonds, in addition to those of the Watson-Crick (W-C) base pairs, in the triplex structure. These new hydrogen bonds are likely to correspond to the interaction between third-strand guanine NH1 imino protons and the N7 atoms of guanine residues on the purine strand of the underlying duplex. Thermal denaturation of the triplex proceeds to single strands in one step, under the conditions used in this study. Binding of the third strand appears to enhance the thermal stability of the duplex by 1-3 degrees C, depending on the DNA concentration. The free energy of triplex formation (-26.0 +/- 0.5 kcal/mol) is approximately twice that of duplex formation (-12.6 +/- 0.7 kcal/mol), suggesting that the overall stability of the pur.pur base pairs is similar to that of the W-C base pairs.(ABSTRACT TRUNCATED AT 250 WORDS)
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), May 1, 1986
Structural determinations of oligonucleotides and their complexes using distance measurements bas... more Structural determinations of oligonucleotides and their complexes using distance measurements based on NOE data are limited due to the relatively short distances available from this technique (less than or equal to 5 A). Extension of NMR measurements to longer distances would greatly augment the information currently obtainable. Effects over a range of approx.20 A can be observed by the incorporation of a paramagnetic spin label at a unique site into an oligomer by establishing a linewidth gradient with an r/sup -6/ dependence on the electron-proton distance. They have therefore synthesized a nonpalindromic oligonucleotide duplex with the sequence /sup 5'/CCACGG./sup 5'/CCGTGG as well as the two corresponding oligonucleotides containing 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (TEMPO) attached by a phosphodiester linkage to the 5'terminus. The /sup 1/H NMR spectra obtained at 500 MHz of the spin-labeled duplexes have been analyzed and the resonances assigned. The extent of line broadening for the nucleotide resonances of the labeled duplexes has been measured and correlated to the distance between the label and the average proton position based on the crystal structure of B-DNA. This study suggests that it is feasible to acquire information over longer distances for the determination of solution structures of oligonucleotides and oligonucleotide:ligand complexes by distancemore » geometry algorithms.« less
α-Santalol, one of the primary components of the East Indian sandalwood oil (EISO), has been inve... more α-Santalol, one of the primary components of the East Indian sandalwood oil (EISO), has been investigated for its potential use as a chemopreventive agent in skin cancer. Although there is some evidence that α-santalol could be an effective chemopreventive agent, to date, purified EISO has not been investigated. EISO is widely used for its health benefits in cultures around the world. In the current study, we show for the first time that EISO-treatment of cultured keratinocytes inhibits cell cycle progression and UV-induced AP-1 activity, two major cellular effects known to drive skin carcinogenesis. Unlike many chemopreventive agents, inhibition of signaling upstream of AP-1 was not a primary means of EISO-mediated AP-1 inhibition, as no effect of EISO was observed on UV-induced Akt, ERK, and p38 MAPK activity. EISO induced cell death at low concentrations, although caspase and PARP cleavage were not observed indicating that death was not due to apoptosis. Interestingly, plasma membrane integrity was severely compromised in EISO-treated cells and LC3 cleavage suggests the induction of autophagy. These effects were more pronounced in EISO-treated cells that were stimulated to proliferate than in quiescent cells. Together, these effects suggest that EISO has chemopreventive properties and may be useful as in preventing skin carcinogenesis. Citation Format: Corey Levenson, Erik R. Olson, David S. Alberts, G. Tim Bowden. A novel chemopreventive mechanism for a traditional medicine: East Indian sandalwood oil induces autophagy and cell death in proliferating keratinocytes. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2254. doi:10.1158/1538-7445.AM2013-2254
Journal of Natural Products, May 20, 2015
Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, with no ... more Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, with no major advancements in treatment over the past 40 years. The current study explores the biological effects of East Indian sandalwood oil (EISO) and its two major constituents, αand β-santalol, against a variety of HNSCC lines. All three agents exhibited cytotoxic effects and caused accumulation of cells in the G2/M phases of the cell cycle. Additionally, treatment with these agents caused formation of multipolar mitotic spindles similar to those observed upon treatment of cells with compounds that affect microtubule polymerization. Indeed, the santalols, as well as EISO, inhibited the polymerization of purified tubulin, indicating for the first time that these compounds have the ability to directly bind to tubulin and affect microtubule formation. Modeling studies suggest that the santalols can weakly bind to the colchicine site on tubulin, and topical administration of EISO to a HNSCC xenograft inhibited tumor growth with no observed toxicities. Therefore, santalols can directly interact with tubulin to inhibit the polymerization of microtubules, similarly to established classes of chemotherapeutic agents, albeit with greatly reduced potency that is not associated with the classic toxicity associated with most other compounds that interact directly with tubulin.
Journal of Medicinal Chemistry, Feb 1, 1984
Three new heterocyclic analogues (4-6) of dihydroorotic acid were designed, synthesized, and test... more Three new heterocyclic analogues (4-6) of dihydroorotic acid were designed, synthesized, and tested as inhibitors of dihydroorotase. Each compound possessed a tetrahedral sulfur atom at the position equivalent to carbon 4 in the dihydroorotate ring in an attempt to mimic the presumed tetrahedral transition state in the course of the enzymatic reaction. Additionally, N-carbamyl-3-phosphonoalanine was prepared and evaluated as a dihydroorotase inhibitor. Compounds 4 and 6 were modest inhibitors (Zm's of 0.52 and 0.18 mM, respectively), but the other candidate inhibitors showed little inhibition at 1 mM. Dihydroorotase (EC 3.5.2.3) catalyzes the cyclization of N-carbamylaspartate (1) to dihydroorotate (2), the third Scheme I r-0, +>+OH 12
Journal of Biological Chemistry, Mar 1, 1995
Journal of Medicinal Chemistry, Aug 1, 1988
Reaction of the trimethylsilylated derivative of 1,4-thiazin-3-one with l-O-acetyl-2,3,5-triO -be... more Reaction of the trimethylsilylated derivative of 1,4-thiazin-3-one with l-O-acetyl-2,3,5-triO -benzoyl-~-ribofuranose in the presence of SnC4 gave, after deblocking, 4-P-~-ribofuranosyl-1,4-thiazin-3-one (8). Treatment of 1,4-thiazin-3-one with l-chloro-2-deoxy-3,5-di-O-p-toluoyl-cu-~-erythro-pentofuranose in the presence of sodium hydride provided, after deblocking, the corresponding 2-deoxy-/3-~-ribofuranosyl derivatives (19). Oxidation of 4-(2,3,5-tri-Obenzoyl-~-~-ribofuranosyl)-l,4-thiazin-3-one (7) with 1 equiv of m-chloroperbenzoic acid resulted in 4-(2,3,5-tri-Obenzoyl-~-~-ribofuranosyl)-1,4-thiazine-2,3-dione (9) and 4-(2,3,5-tri-0-benzoyl-~-~-ribofuranosyl)-l,4-thiazin-3-one 1-oxide (10). Evidence is presented that indicates that the oxidation of the thiazine at the 2-position is due to a Pummerer rearrangement. The new compounds failed to show significant activity against tumor cell lines in culture, L1210 cells in vivo, virus cytotoxicity in cell culture, or cytidine deaminase.
Journal of Biomolecular Structure & Dynamics, Apr 1, 1987
The nonexchangeable base and sugar protons of the octanucleotide d(ACCCGGGT)2 have been assigned ... more The nonexchangeable base and sugar protons of the octanucleotide d(ACCCGGGT)2 have been assigned using two dimensional homonuclear Hartmann-Hahn relayed spectroscopy (HOHAHA), double quantum filtered homonuclear correlation spectroscopy (DQFCOSY) and nuclear Overhauser spectroscopy (NOESY) in D2O at 12 degrees C. The observed NOE's between the base protons and their own H2' protons and between the base protons and the H2' protons of the 5' adjacent nucleotide and the observed coupling constants between the deoxyribose 1' and 2',2'' protons indicate that this duplex assumes a right-handed B-type helix conformation in solution.
Elsevier eBooks, 1987
Publisher Summary The development of oligonucleotide-directed site-specific mutagenesis on single... more Publisher Summary The development of oligonucleotide-directed site-specific mutagenesis on single-stranded phage template has provided a powerful new technique in the study of structure-function relationships of proteins. This chapter describes a simplified procedure for oligonucleotide-directed site-specific mutagenesis on M13 single-stranded phage deoxyribo nucleic acid (DNA) templates. The rationale behind this approach is to make use of the DNA repair mechanism present in the E. coli host to repair the gapped M13 phage DNA into the covalently closed circular form before replication of the DNA molecules. The mutagenesis procedure described in this chapter provides a rapid method for the modification of cloned genes. It takes advantage of the ability of E. coli to efficiently repair gapped circular DNA molecules, to shorten the overall time of the mutagenesis, from initiation of the mutagenesis reaction to the identification of the mutant phage plaque. Although this faster method is less efficient in the conversion of parent DNA to mutant DNA molecules, the ability to use the same oligonucleotide primer as a probe to identify the mutant phage plaques effectively compensates for this inefficiency.
Nature Biotechnology, Mar 1, 1989
Industrial Crops and Products, Nov 1, 2019
The East Indian sandalwood oil has been widely used as an Ayurvedic medicine and has multiple pha... more The East Indian sandalwood oil has been widely used as an Ayurvedic medicine and has multiple pharmacological properties. However, antioxidant and antistress potency of East Indian sandalwood oil against oxidative stress-induced damages remain unexplored. Thus, the present study was aimed to investigate the in vitro and in vivo antioxidant and stress-protective properties of essential oil extracted from the heartwood of plantationgrown Santalum album L. (SEO). The SEO was extracted by traditional stream distillation method and the chemical components were determined via gas chromatography-mass spectrometry (GC-MS) analysis. Nineteen chemical compounds were identified by GC-MS, accounting for 96.81% of total oil. The main components were α-santalol (41.77%), β-santalol (18.02%), (Z)-α-trans-bergamotol (8.50%), (Z)-lanceol (6.57%), and epi-β-santalol (5.78%). The in vitro results suggests that SEO possess an excellent antioxidant activity as it was able to inhibits the intracellular reactive oxygen species (ROS) generation, reverse the morphological damages and effectively improves viability of neural cells under oxidative stress conditions. Moreover, SEO markedly increased the antioxidant enzyme activities of superoxide dismutase, catalase, and glutathione peroxidase. Western blotting results further confirmed that SEO protects neural cells against oxidative damages possibly by activating the nuclear factor-erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) antioxidant mechanism. The SEO also exhibited a strong in vivo antioxidant and stress modulatory activity on Caenorhabditis elegans. The SEO not only acts protective against oxidative stress but also prolongs the lifespan of mev-1 mutant C. elegans having shortened lifespan due to the over production of ROS. This data confirmed that SEO exert potent antioxidant and stress modulatory activities possibly by direct scavenging of free radicals and activation of antioxidant defense system, in vitro and in vivo. Together, these findings indicated that SEO has the potency to be utilized as a source of antioxidant for treating several degenerative and disease conditions caused by oxidative stress.
The New England Journal of Medicine, Sep 1, 1988
We have developed a simple and rapid nonradioactive method for detecting genetic variation and ha... more We have developed a simple and rapid nonradioactive method for detecting genetic variation and have applied it to the diagnosis of sickle cell anemia and beta-thalassemia. The procedure involves the selective amplification of a segment of the human beta-globin gene with oligonucleotide primers and a thermostable DNA polymerase, followed by hybridization of the amplified DNA with allele-specific oligonucleotide probes covalently labeled with horseradish peroxidase. The hybridized probes were detected with a simple colorimetric assay. We demonstrated the usefulness of this method in a retrospective analysis of two pregnancies at risk for beta-thalassemia and one at risk for sickle cell anemia, as well as in an analysis of nine DNA samples simulating three family sets.