Two-photon-induced cycloreversion reaction of coumarin photodimers

Kim, H. C.; Kreiling, Stefan; Greiner, Andreas; Hampp, Norbert

doi:10.1016/s0009-2614(03)00535-9

Cited by 70 publications

(52 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While they were able to quantitatively cleave the dimers, the dose necessary for the reaction was approximately 9.0 kJ at 532 nm, whereas for the same unit area less than 500 mJ was necessary to cleave the dimer at 266 nm. 89 …”

Section: Photodimerization and Photocleavagementioning

confidence: 99%

Coumarins in Polymers: From Light Harvesting to Photo-Cross-Linkable Tissue Scaffolds

et al. 2004

View full text Add to dashboard Cite

Section: Photodimerization and Photocleavagementioning

confidence: 99%

Coumarins in Polymers: From Light Harvesting to Photo-Cross-Linkable Tissue Scaffolds

et al. 2004

View full text Add to dashboard Cite

“…Kim and colleagues had shown 23 that the optical spectrum of coumarin changes with its dimerization. Based on this publication, we named the dimeric; we named the dimeric form of the compound (λ max <300 nm) as Cm1 and its monomer form (λ max = 310 nm) as Cm2.…”

Section: The Influence Of Plant Fractions On the Viability Of β-Cellsmentioning

confidence: 99%

Untitled

2015

IJPSR

View full text Add to dashboard Cite

Misfolding of some proteins, their self-assembly into insoluble amyloid structures underlies many diseases, constituting a group of amyloid-related pathology. Fibrillation of peptide hormone of the pancreas, amylin, is considered as one of the causes of death of β-cells in type 2 diabetes. In this work we studied in-vitro protection of islet β-cells from death in the presence of aggregated amylin by ethanol extracts of rose petals (Rosa damascena), melilot (Melilotus officinalis), leaves of grape (Vitis vinifera), sorrel (Rumex confertus) and blackberry (Rubus caesius), and by eleven fractions, isolated from these plants (Coumarin, phenol glycoside, flavonoid and anthracene derivative). A rather low IC 50 values in protection of β-cells were estimated for the extracts (0.03-1.5 µg/ml) and their fractions (0.04-3.9 µg/ml). The inhibition of amylin aggregation by several plant extracts and fractions in-vitro was studied using ThT fluorescence method. The IC 50 values in deceleration of the peptide aggregation were between 1.76-7.24 µg/ml. A strong correlation (r = 0.99, p=0.0005) was observed between IC 50 values in the protection of β-cells and amylin aggregation. Probably, both of these processes are conditioned by prevention of amylin aggregation and decomposition of its preformed aggregates by plant preparations. These results allow recommending frequent use of effective plants by persons at risk group and considering these plants as sources for anti-diabetic agents.

show abstract

“…No significant release was observed until the ratio increased to 1:0.1, where the release degree increased up to 25% for 60 min. It is well known that coumarin and its derivatives are dimerized by a UV light [8][9][10][11][12]. EPC residues of HmPVA-EPC conjugate immobilized on the surface of liposome could have been photo-dimerized, and subsequently HmPVA could have taken a contracted form due to the dimerization.…”

Section: Photo-responsive Release From Egg Pc Liposomes Incorporatingmentioning

confidence: 99%

“…Under the irradiation of l > 310 nm, coumarin and its derivative are dimerized through the formation of cyclobutane bridges. The dimers are reversibly cleaved to monomers by the irradiation of l < 254 nm [9][10][11][12]. Coumarins in liposomal membranes also can be dimerized and de-dimerized, and perturb the membranes, leading to a photo-triggered release.…”

Section: Introductionmentioning

confidence: 99%