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Organochalcogen Substituents in Phenolic Antioxidants
Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi. (Lars Engman)
Vise andre og tillknytning
2010 (engelsk)Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 12, nr 10, s. 2326-2329Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Little is known about the ED/EW character of organochalcogen substituents and their contribution to the O-H bond dissociation enthalpy (BDE) in phenolic compounds. A series of ortho- and para-(S,Se,Te)R-substituted phenols were prepared and investigated by EPR, IR, and computational methods. Substituents lowered the O-H BDE by >3 kcal/mol in the para position, while the ortho-effect was modest due to hydrogen bonding ( approximately 3 kcal/mol) to the O-H group.

sted, utgiver, år, opplag, sider
2010. Vol. 12, nr 10, s. 2326-2329
HSV kategori
Identifikatorer
URN: urn:nbn:se:uu:diva-122483DOI: 10.1021/ol100683uISI: 000277531000040PubMedID: 20405887OAI: oai:DiVA.org:uu-122483DiVA, id: diva2:310244
Tilgjengelig fra: 2010-04-13 Laget: 2010-04-13 Sist oppdatert: 2017-12-12bibliografisk kontrollert
Inngår i avhandling
1. Exploring Novel Catalytic Chalcogenide Antioxidants
Åpne denne publikasjonen i ny fane eller vindu >>Exploring Novel Catalytic Chalcogenide Antioxidants
2010 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis is concerned with the synthesis and evaluation of regenerable chalcogen containing antioxidants. Variously substituted 2,3-dihydrobenzo[b]selenophene-5-ol antioxidants were evaluated in order to gain information about structure/reactivity-relationships. Within the series explored, the most regenerable unsubstituted compound inhibited lipid peroxidation for more than 320 minutes when assayed in a two-phase lipid peroxidation model in the presence of N-acetylcysteine (NAC). α-Tocopherol which could inhibit lipid peroxidation for 90 minutes under similar conditions was therefore easily outperformed. The antioxidant activity of the parent was also documented in an aqueous environment. The best catalyst quenched/inhibited ROS production by neutrophils and PMA-stimulated macrophages more efficiently than Trolox. In addition, over a period of seven days, no disruption in proliferation for the cell lines used was observed when exposed to our synthetic compound or Trolox at a concentration of 60 µM.

3-Pyridinols substituted with alkyltelluro groups in the ortho-position were more regenerable in the two-phase model than their corresponding para-substituted analogues in the presence of NAC and also inhibited autoxidation of styrene in a catalytic fashion in homogenous phase in the presence of N-tert-butoxycarbonyl cysteine methyl ester (LipCys), a lipid-soluble analogue of NAC. The best inhibitors quenched peroxyl radicals more efficiently than α-tocopherol. They could also catalyze reduction of organic hydroperoxides in the presence of thiols and therefore mimic the action of the glutathione peroxidase enzymes. Mechanisms for the catalysis are proposed.

Octylthio, octylseleno and octyltelluro analogues of butylated hydroxyanisole (BHA) were synthesized and evaluated. Among these, the tellurium compound was superior to α-tocopherol in the presence of NAC both when it comes to quenching capacity and regenerability.  Organochalcogen substituent effects in phenolic compounds were studied by using EPR, IR and computational methods.

sted, utgiver, år, opplag, sider
Uppsala: Acta Universitatis Upsaliensis, 2010. s. 71
Serie
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 742
Emneord
antioxidant, tellurium, selenium, catalytic, toxicity, ROS, neutrophil, glutathione peroxidase mimic, macrophage.
HSV kategori
Forskningsprogram
Kemi med inriktning mot organisk kemi
Identifikatorer
urn:nbn:se:uu:diva-122485 (URN)978-91-554-7803-2 (ISBN)
Disputas
2010-06-03, B41, BMC, Husargatan 3, 751 23, Uppsala, 10:15 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2010-05-11 Laget: 2010-04-13 Sist oppdatert: 2010-05-18

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