Antitumor agents. 21. A proposed mechanism for inhibition of cancer growth by tenulin and helenalin and related cyclopentenones

Hall, Iris H.; Lee, Kuo Hsiung̀; Mar, Eng-Chun; Starnes, C.O.; Waddell, Thomas G.

doi:10.1021/jm00213a003

Cited by 147 publications

(45 citation statements)

References 8 publications

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“…Of the four chemicals used in this study the greatest potentiation of cytotoxicity in the presence of BSO was exhibited by helenalin (Table I and Figure 2). GSH may protect against helenalin cytotoxicity by conjugation, prior to alkylation of target molecules, prevent cross linking or restore critical sulphydryl groups (Hall et al, 1977(Hall et al, , 1978. It is of interest to note that in the presence of helenalin (1-10 MM), LoVo cell GSH Was not depleted, suggesting that modulation of GSH may be of importance in determining the toxicity of agents that do not deplete GSH.…”

Section: Discussionmentioning

confidence: 99%

Effects of glutathione depletion on the cytotoxicity of agents toward a human colonic tumour cell line

Jordán¹,

Doherty²,

Cohen³

1987

Br J Cancer

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Summary Levels of glutathione (GSH) in tumour tissue may be important in determining the clinical response to certain anticancer agents. Recent reports have suggested that D,L-buthionine-S,R-sulphoximine (BSO), a specific inhibitor of GSH synthesis, may be used to deplete tumour cell GSH and thus increase the therapeutic ratio of these agents. We have previously shown that 1-naphthol is a potential antitumour agent, and that its possible metabolite 1,4-naphthoquinone is thiol reactive and capable of redox cycling. It was therefore of interest to investigate the effect of pretreatment with BSO, on the toxicity of these agents, to tumour cells. For comparison we included three other cytotoxic agents, melphalan, helenalin and menadione, the toxicities of which are reported to be modulated by intracellular GSH. Depletion of GSH using BSO did not effect the toxicity of 1-naphthol, or 1,4-NQ but did produce slight potentiation of the cytotoxicities of menadione, helanalin and melphalan. The lack of effect of BSO on 1-naphthol and 1,4-NQ is not easily explained but if one also considers the modest potentiation of cytotoxicity achieved with the other agents studied, the potential use of BSO in combined chemotherapy is at best rather modest.Based on our findings that l-naphthol is selectively toxic to short term organ cultures of human colonic tumour tissue compared to normal colonic tissue from the same patients, we suggested the potential use of l-naphthol or related compounds in cancer chemotherapy (Cohen et al., 1983;Wilson et al., 1985). Recently we have also shown an antitumour activity of l-naphthol against Ehrlich ascites tumour cells (Jones et al., 1987) and it therefore is of interest to elucidate its mechanism of toxicity and formation of possible reactive metabolites. l-Naphthol may be metabolised by a microsomal mixed function oxidase to cytotoxic naphthoquinones, primarily 1,4-naphthoquinone (d'Arcy Doherty et al., 1984a, b, 1985). The toxicity of both 1-naphthol and its possible metabolites 1,2-naphthoquinone and 1,4-naphthoquinone, to isolated hepatocytes, is prececed by a rapid depletion of intracellular glutathione (GSH) (d 'Arcy Doherty et al., 1984b).GSH is the major nonprotein thiol in the cell and plays a critical role in cellular defences against oxidative stress, free radicals and alkylating agents (Meister & Anderson, 1979). One of the problems associated with chemotherapy is the wide range of sensitivities to treatment with any or one agent, which is thought to be, in part, due to the differences in sulphydryl levels in tumours. Several recent reports, have therefore considered the potential of modulating intracellular GSH levels in order to increase the chemotherapeutic efficacy of certain antitumour agents, whose toxicity is modulated by GSH (Akman et al., 1985;Arrick et al., 1983;Capranico et al., 1986;Hamilton et al., 1985;Russo et al., 1986;Suzukake et al., 1982Suzukake et al., , 1983.The cytotoxic and antitumour effects of certain quinones e.g. adriamycin and menadione, are thought to be r...

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Section: Discussionmentioning

confidence: 99%

Effects of glutathione depletion on the cytotoxicity of agents toward a human colonic tumour cell line

Jordán¹,

Doherty²,

Cohen³

1987

Br J Cancer

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“…The performance of CWO reported here is similar to results reported by Ghanem and Olama (2014) on the stem methanolic extract from Lebanese Cedar (Cedrus linani) on E. coli, Listeria monocytogenes, and Candida albicans due to the presence ofterpenes, a-and b-pinene, a-and b-cedrene, and cedrol (Adams 1991;Guerrini 2011). According to Hall et al (1977), the proposed mechanism of antimicrobial activity of sesquiterpenes compounds of CWO is in their reaction with thiol groups of enzymes necessary for DNA replication, which greatly hindered the production of bacterial.…”

Section: Mechanical Properties Of the Filmsmentioning

confidence: 99%

Antimicrobial activity of sugar beet lignocellulose films containing tung oil and cedarwood essential oil

Shen

Kamdem

2015

Cellulose

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Several studies have been reported on the use of cellulose, lignocellulose, chitin and other biological macromolecules for food packaging. One of the major drawbacks limiting their wide uses is their limited antimicrobial and water vapor barrier properties. In this study, cedarwood (Thuja occidentalis) essential oil (CWO), known to contain terpenes, polyphenols and tung oil, known to contain fatty acids, were used as additives to improve water vapor barrier, antimicrobial, and physical properties of laboratory cast lignocellulose films. Physicochemical and mechanical properties were tested to evaluate the impact of the addition of oils in the films formulations. The addition of 15 % CWO and tung oils improved water vapor permeability by more than 25 % as also evidenced by the increase of contact angle between water and film by 134 % from 38.98°to 89.36°with 15 % tung oil. FTIR was used to monitor the presence of hydrophobic groups at 1463 and 1741 cm -1 from the oil on the film spectra confirming the improvement of film hydrophobicity from oils interactions. However, the addition of 15 % hydrophobic oils promoted a significant decrease in tensile properties of films (p B 0.05) by 40 % for CWO and 32 % for tung oil, respectively, due to a partial incompatibility between hydrophilic lignocellulose and hydrophobic oils. The use of a tailored coupling agent to reduce the incompatibility and to improve the load charge transfer between hydrophobic and hydrophilic group might reduce the decrease of the tensile properties with the addition of hydrophobic compounds. No significant difference (p [ 0.05) was observed on the thermal stability of films using TGA. The antimicrobial effects of lignocellulose films against bacteria namely Listeria innocua, Escherichia coli, and Salmonella enterica was tested by disk inhibition zone method and showed an improvement with the addition of 5 % CWO in the film. The Microbe Growth Index of the lignocellulose cellulosic films containing 20 % w/w of CWO decreases by 80 %. CWO and tung oil are good candidates to control microbial growth and water vapor permeability in flexible films. Future work will focus on the olfactory and tensile properties for applications in food packaging.

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“…2 This reaction also plays also critical roles in the biosynthesis and synthesis of bioactive compounds. 3,4 Besides, the 1,4-addition is a highly atom-efficient, green reaction, in agreement with the second principle of green chemistry, which says that the synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. [5][6][7] In view of these aspects, there are a large number of reported methods for both basic and acidic promoted selective 1,4-additions, including heterogeneous [8][9][10][11][12][13][14][15][16] and homogeneous catalysis, [17][18][19] as well as asymmetric versions.…”

Section: Introductionmentioning

confidence: 81%

Green Michael addition of thiols to electron deficient alkenes using KF/alumina and recyclable solvent or solvent-free conditions

Lenardão¹,

Trecha²,

Ferreira³

et al. 2009

J. Braz. Chem. Soc.

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Um método simples e eficiente foi desenvolvido para a adição conjugada de tióis ao citral na presença de KF/Al 2 O 3 em meio livre de solvente ou usando glicerina como solvente reciclável a temperatura ambiente. O método em meio livre de solvente foi aplicado com sucesso na reação direta do tiofenol com o óleo essencial de capim limão (Cymbopogon citratus), para fornecer diretamente 3,7-dimetil-3-(feniltio)oct-6-enal, um potencial agente bactericida. O método foi estendido a outros alcenos deficientes de elétrons com excelentes resultados. Para o método em meio livre de solvente, o uso de irradiação com microondas facilitou o procedimento e acelerou a reação. O sistema catalítico e a glicerina podem ser reutilizados até três vezes sem tratamento prévio, com atividade comparável.A general, clean and easy method for the conjugated addition of thiols to citral promoted by KF/ Al 2 O 3 under solvent-free or using glycerin as recyclable solvent at room temperature is described. It was found that the solvent-free protocol is applicable to the direct reaction of thiophenol with the essential oil of lemon grass (Cymbopogon citratus) to afford directly 3,7-dimethyl-3-(phenylthio) oct-6-enal, a potential bactericide agent. The method was extended to other electron-poor alkenes with excellent results. For the solvent-free protocol, the use of microwave irradiation facilitated the procedure and accelerates the reaction. The catalytic system and glycerin can be reused up to three times without previous treatment with comparable activity.

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Antitumor agents. 21. A proposed mechanism for inhibition of cancer growth by tenulin and helenalin and related cyclopentenones

Cited by 147 publications

References 8 publications

Effects of glutathione depletion on the cytotoxicity of agents toward a human colonic tumour cell line

Effects of glutathione depletion on the cytotoxicity of agents toward a human colonic tumour cell line

Antimicrobial activity of sugar beet lignocellulose films containing tung oil and cedarwood essential oil

Green Michael addition of thiols to electron deficient alkenes using KF/alumina and recyclable solvent or solvent-free conditions

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