| 1. |
- Andersson Dunstan, Christina, et al.
(författare)
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Alphitol, a phenolic substance from Alphitonia zizyphoides which inhibits prostaglandin biosynthesis in vitro
- 1998
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Ingår i: Phytochemistry. - 0031-9422 .- 1873-3700. ; 48:3, s. 495-497
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Tidskriftsartikel (refereegranskat)abstract
- The new phenolic compound, 3,5-dihydroxy-4-methoxy phenethyl alcohol, named alphitol, and betulinic acid were isolated from the bark of Alphitonia zizyphoides. The chemical structure of alphitol was determined by mass spectrometry in combination with one and two dimensional NMR, including HMBC. Both compounds inhibited prostaglandin biosynthesis in vitro, alphitol with an IC50 value of 0.66 mM, which is of the same magnitude as acetyl salicylic acid.
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| 2. |
- Andersson Dunstan, Christina, et al.
(författare)
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Evaluation of some Samoan and Peruvian medicinal plants by prostaglandin biosynthesis and rat ear oedema assays
- 1997
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Ingår i: Journal of Ethnopharmacology. - 0378-8741 .- 1872-7573. ; 57:1, s. 35-56
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Tidskriftsartikel (refereegranskat)abstract
- In our ongoing program to find new anti-inflammatory compounds, 58 extracts from 46 different medicinal plant species, used in treatment of inflammatory disorders - 38 plants from the traditional medicine of Western Samoa and eight originating from the indigenous medicine of the Shipibo-Conibo tribe of Peruvian Amazonia - were evaluated. The ability of all extracts to inhibit cyclooxygenase-1 catalysed prostaglandin biosynthesis in vitro was examined. Of the plant species tested 14 showed moderate to strong inhibition; including 11 Samoan and three Peruvian species. Further, 12 Samoan and all eight Peruvian species were investigated on their inhibitory activity of ethyl phenylpropiolate induced rat ear oedema in vivo Significant activity was shown by 10 of the Samoan and by all eight Peruvian species. An additional evaluation of the most active species was provided through a compilation of existing literature documenting traditional medicinal uses, pharmacological activity and chemical constituents. Several known cyclooxygenase-l inhibitors were reported to which the observed pharmacological activity can be attributed at least partly. The combination of chemical and pharmacological literature data and our experimental data may help to explain the anti-inflammatory use of these species in indigenous medicine.
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| 3. |
- Bohlin, Anna, et al.
(författare)
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Perceived gender inequality in the couple relationship and musculoskeletal pain in middle-aged women and men
- 2013
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Ingår i: Scandinavian Journal of Public Health. - : Sage Publications. - 1403-4948 .- 1651-1905. ; 41:8, s. 825-831
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Musculoskeletal pain is a major health problem, especially in women, and is partially determined by psychosocial factors. The aim of the present study was to investigate whether gender inequality in the couple relationship was related to musculoskeletal pain. Methods: Participants (n=721; 364 women and 357 men) were all individuals living in a couple relationship in the Northern Swedish Cohort, a 26-year Swedish cohort study. Self-administered questionnaire data at age 42 years comprised perceived gender inequality in the couple relationship and musculoskeletal pain (in three locations, summarised into one score and median-split), concurrent demographic factors, psychological distress, and previous musculoskeletal pain at age 30 years. Associations were examined using logistic regression. Results: Gender inequality was positively associated with symptoms of musculoskeletal pain in the total sample, remaining significant after addition of possible confounders and of previous musculoskeletal pain. Separate adjustment for concurrent psychological distress attenuated the association but not below significance. The association was present and of comparable strength in both women and men. Conclusions: Gender inequality in the couple relationship might contribute to the experience of musculoskeletal pain in both women and men. The results highlight the potential adverse bodily consequences of living in unequal relationships.
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| 4. |
- Bohlin, Christina, 1979-, et al.
(författare)
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Diastereomer selectivity in the degradation of a lignin model compound of the arylglycerol β-aryl ether type by white-rot fungi
- 2008
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Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229 .- 1879-0909. ; 43:2, s. 199-204
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Tidskriftsartikel (refereegranskat)abstract
- Mixtures of about equal amounts of the diastereomers of arylglycerol β-aryl ether 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (1) were added to cultures of Trametes versicolor, Phanerochaete chrysosporium, and Pycnoporus cinnabarinus. Samples taken from the fungal cultures were analyzed with respect to the fraction of 1 degraded, the erythro:threo ratio in the remaining 1, and the product profile, using HPLC and UV-diode array detector. The P. cinnabarinus cultures exhibited laccase activity and partially decolorized Remazol Brilliant Blue R (RBBR), but they did not degrade 1 under the conditions studied. Cultures of T. versicolor and P. chrysosporium preferentially degraded the threo isomer of 1. This is consistent with the fact that the product profiles showed larger amounts of threo- than erythro-veratrylglycerol. The results can be discussed in relation to the diastereomer selectivity of various oxidants implicated in lignin degradation by white-rot fungi. Preferential degradation of the threo isomer of arylglycerol β-aryl ethers is not in agreement with the action of Fenton's reagent, since this reagent does not exhibit any stereopreference.
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| 5. |
- Bohlin, Christina, et al.
(författare)
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Differences in stereo-preference in the oxidative degradation of diastereomers of the lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol with enzymic and non-enzymic oxidants
- 2007
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Ingår i: Journal of Molecular Catalysis - B Enzymatic. - : Elsevier BV. - 1381-1177 .- 1873-3158. ; 45:1-2, s. 21-26
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Tidskriftsartikel (refereegranskat)abstract
- Mixtures of equal amounts of the erythro and the threo forms of the β-O-4 lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol were oxidized with different ligninolytic enzymes and non-enzymic oxidants. The oxidants included cerium(IV)ammonium nitrate (CAN), Fenton’s reagent, lead(IV) tetraacetate (LTA), laccase, laccase–mediator systems (based on the mediators ABTS, HBT,TEMPO, and VLA), and lignin peroxidase. The stereo-preference of the different oxidants was compared based on analyses of remaining substrateusing HPLC and UV-diode array detector or 1H NMR spectroscopy. Fenton’s reagent was the only oxidant tested that did not show preferentialdegradation of either the erythro or the threo form. CAN, LTA and lignin peroxidase preferentially oxidized the threo form. The stereo-preferenceof the laccase–mediator systems depended on the mediator. Oxidation mediated by HBT, TEMPO or VLA resulted in a preferential degradationof the threo form. Laccase/ABTS was the only system tested that showed preferential oxidation of the erythro form. The stereo-preference of theoxidants is discussed based on their redox potentials and their classification as outer-sphere and inner-sphere oxidants.
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| 6. |
- Bohlin, Christina
(författare)
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In vitro and in vivo oxidation of diastereomers of lignin models of arylgylcerol b-aryl ether type and heterologous expression of laccase
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Enzymic and non-enzymic oxidation of lignin models of the arylglycerol β-aryl ether type was investigated in experiments aimed at providing a better understanding of the initial phase of biological lignin degradation. Product profiles and diasteromer selectivity were determined to gain knowledge of the properties of the oxidants and pave the way for evaluation of the presence of the oxidants in ligninolytic fungal cultures. Diastereomers of the non-phenolic lignin model 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (1) were oxidized in vitro with lignin peroxidase (LP), laccase-mediator systems, Fenton's reagent, cerium(IV) ammonium nitrate (CAN) and lead(IV) tetraacetate. The product profiles were found to be distinctive for the different oxidants, except for LP and CAN, which generated the same products in similar proportions. The reactions resulted in preferential degradation of the threo isomer, except for the Fenton's reagent reaction, which showed no stereo-preference, and the laccase reaction mediated by ABTS, which preferentially degraded the erythro isomer. Cultures of the white-rot fungi Trametes versicolor and Phanerochaete chrysosporium preferentially degraded the threo isomer of 1. This is not in agreement with the action of Fenton's reagent, since this oxidant does not exhibit any stereo-preference. Laccase from T. versicolor was expressed in Pichia pastoris and Aspergillus niger. Production of catalytically active T. versicolor laccase was achieved in both P. pastoris and A. niger using glyceraldehyde-3-phosphate dehydrogenase promoters. The level of laccase activity obtained with P. pastoris was significantly lower than that obtained with A. niger, but speed and convenience make the P. pastoris system attractive for screening purposes. A. niger produced high yields of heterologous laccase with properties similar to those of the native enzyme. A method was devised to purify laccase from cultures of A. niger. The method gave a 250-fold purification and a yield of >50%.
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| 7. |
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| 8. |
- Bohlin, Christina, et al.
(författare)
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Oxidation of the erythro and threo forms of the phenolic lignin model compound 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol by laccases and model oxidants
- 2009
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Ingår i: Bioorganic chemistry (Print). - : Elsevier. - 0045-2068 .- 1090-2120. ; 37:5, s. 143-148
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Tidskriftsartikel (refereegranskat)abstract
- Mixtures of equal amounts of the erythro and threo forms of the phenolic arylglycerol β-aryl ether 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol were oxidized (i) with laccases from Trametes versicolor, Agaricus bisporus, Myceliophthora thermophila and Rhus vernicifera, (ii) with laccase-mediator systems consisting of T. versicolor laccase and ABTS or HBT, and (iii) with various model oxidants including cerium(IV) ammonium nitrate (CAN), lignin peroxidase, Fenton’s reagent, and lead(IV) tetraacetate (LTA). All the laccases exhibited a similar preferential degradation of the threo form. The mediator ABTS counteracted the threo preference of laccase, but the mediator HBT did not affect it. The outer-sphere model oxidants CAN and lignin peroxidase showed a preferential degradation of the threo form. LTA and Fenton’s reagent did not exhibit any stereo-preference. The results suggest that laccases of different origin, primary structure, and redox potential behave as typical outer-sphere oxidants in their interaction with the diastereomers of the arylglycerol β-aryl ether
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| 9. |
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| 10. |
- Bohlin, Christina, et al.
(författare)
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Product profiles in enzymic and non-enzymic oxidations of the lignin model compound erythro-1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol
- 2005
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Ingår i: Journal of Molecular Catalysis - B Enzymatic. - : Elsevier BV. - 1381-1177 .- 1873-3158. ; 35:4-6, s. 100-107
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Tidskriftsartikel (refereegranskat)abstract
- The erythro form of the lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (1) was oxidized with laccase/ABTS, lead(IV) tetraacetate (LTA), lignin peroxidase/H2O2, cerium(IV) ammonium nitrate (CAN) and Fenton's reagent. The product profiles obtained with the different oxidants were compared after separation, identification and quantification of the products using HPLC, UV-diode array detector and electrospray ionization mass spectrometry in positive ionization mode. The oxidants generated different product profiles that reflected their different properties. Oxidation with laccase/ABTS resulted almost exclusively in formation of 1-(3,4-dimethoxyphenyl)-3-hydroxy-2-(2-methoxyphenoxy)-1-propanone (2). Oxidation with LTA resulted in more 3,4-dimethoxybenzaldehyde (3) than ketone 2. Lignin peroxidase and CAN gave similar product profiles and aldehyde 3 was the predominant product (only small amounts of ketone 2 were formed). Oxidation with Fenton's reagent resulted in the formation of more aldehyde 3 than ketone 2 but the yields were very low. CAN served as an excellent model for the lignin peroxidase-catalyzed oxidation, while the laccase-mediator system, LTA and Fenton's reagent provided distinctly different product profiles. Erythro-1-(3,4-dimethoxyphenyl)-1,2,3-propanetriol was present among the products obtained on oxidation with LTA, lignin peroxidase, CAN and Fenton's reagent. The differences in redox potential between the oxidants afford an explanation of the diverse product patterns but other factors may also be of importance. The reactions leading to cleavage of the β-ether bond with formation of 1-(3,4-dimethoxyphenyl)-1,2,3-propanetriol (veratrylglycerol) were found to proceed without affecting the configuration at the β-carbon atom.
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