Photooxidation of alkaloids: Considerable quantum yield enhancement by rose bengal-sensitized singlet molecular oxygen generation

Helmut Görner, Z. Miskolczy, Mónika Megyesi, L. Biczók

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The photooxidation of sanguinarine, coralyne and berberine was studied in oxygenated alkaline methanol solutions. Rose bengal as photosensitizer significantly accelerates the process, indicating the importance of singlet molecular oxygen in the reaction mechanism. The quantum yield of sensitized oxidation was found to increase significantly with pH and reaches 0.4 for berberine at pH 13.8. The direct oxidation of alkaloids is less efficient, the quantum yield does not exceed 0.01 even in oxygen-saturated solutions. The photoinduced electron ejection does not play a role in the oxidation. The uncharged pseudobase forms, which are present in alkaline medium, are oxidized much more easily than the alkaloid cations. The quantum yield of rose bengal-sensitized photooxidation of berberine and coralyne alkaloids increases significantly with pH. Singlet molecular oxygen plays an important role in the reaction mechanism.

Original languageEnglish
Pages (from-to)1315-1320
Number of pages6
JournalPhotochemistry and Photobiology
Volume87
Issue number6
DOIs
Publication statusPublished - Nov 2011

Fingerprint

coralyne
Berberine
Rose Bengal
Singlet Oxygen
alkaloids
Photooxidation
Molecular oxygen
photooxidation
Quantum yield
Alkaloids
Oxidation
oxidation
augmentation
Berberine Alkaloids
oxygen
Photosensitizing Agents
ejection
Methanol
Cations
methyl alcohol

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Biochemistry
  • Medicine(all)

Cite this

Photooxidation of alkaloids : Considerable quantum yield enhancement by rose bengal-sensitized singlet molecular oxygen generation. / Görner, Helmut; Miskolczy, Z.; Megyesi, Mónika; Biczók, L.

In: Photochemistry and Photobiology, Vol. 87, No. 6, 11.2011, p. 1315-1320.

Research output: Contribution to journalArticle

@article{526b3c5fe4a840edbe54eb6b15d42d5b,
title = "Photooxidation of alkaloids: Considerable quantum yield enhancement by rose bengal-sensitized singlet molecular oxygen generation",
abstract = "The photooxidation of sanguinarine, coralyne and berberine was studied in oxygenated alkaline methanol solutions. Rose bengal as photosensitizer significantly accelerates the process, indicating the importance of singlet molecular oxygen in the reaction mechanism. The quantum yield of sensitized oxidation was found to increase significantly with pH and reaches 0.4 for berberine at pH 13.8. The direct oxidation of alkaloids is less efficient, the quantum yield does not exceed 0.01 even in oxygen-saturated solutions. The photoinduced electron ejection does not play a role in the oxidation. The uncharged pseudobase forms, which are present in alkaline medium, are oxidized much more easily than the alkaloid cations. The quantum yield of rose bengal-sensitized photooxidation of berberine and coralyne alkaloids increases significantly with pH. Singlet molecular oxygen plays an important role in the reaction mechanism.",
author = "Helmut G{\"o}rner and Z. Miskolczy and M{\'o}nika Megyesi and L. Bicz{\'o}k",
year = "2011",
month = "11",
doi = "10.1111/j.1751-1097.2011.00994.x",
language = "English",
volume = "87",
pages = "1315--1320",
journal = "Photochemistry and Photobiology",
issn = "0031-8655",
publisher = "Wiley-Blackwell",
number = "6",

}

TY - JOUR

T1 - Photooxidation of alkaloids

T2 - Considerable quantum yield enhancement by rose bengal-sensitized singlet molecular oxygen generation

AU - Görner, Helmut

AU - Miskolczy, Z.

AU - Megyesi, Mónika

AU - Biczók, L.

PY - 2011/11

Y1 - 2011/11

N2 - The photooxidation of sanguinarine, coralyne and berberine was studied in oxygenated alkaline methanol solutions. Rose bengal as photosensitizer significantly accelerates the process, indicating the importance of singlet molecular oxygen in the reaction mechanism. The quantum yield of sensitized oxidation was found to increase significantly with pH and reaches 0.4 for berberine at pH 13.8. The direct oxidation of alkaloids is less efficient, the quantum yield does not exceed 0.01 even in oxygen-saturated solutions. The photoinduced electron ejection does not play a role in the oxidation. The uncharged pseudobase forms, which are present in alkaline medium, are oxidized much more easily than the alkaloid cations. The quantum yield of rose bengal-sensitized photooxidation of berberine and coralyne alkaloids increases significantly with pH. Singlet molecular oxygen plays an important role in the reaction mechanism.

AB - The photooxidation of sanguinarine, coralyne and berberine was studied in oxygenated alkaline methanol solutions. Rose bengal as photosensitizer significantly accelerates the process, indicating the importance of singlet molecular oxygen in the reaction mechanism. The quantum yield of sensitized oxidation was found to increase significantly with pH and reaches 0.4 for berberine at pH 13.8. The direct oxidation of alkaloids is less efficient, the quantum yield does not exceed 0.01 even in oxygen-saturated solutions. The photoinduced electron ejection does not play a role in the oxidation. The uncharged pseudobase forms, which are present in alkaline medium, are oxidized much more easily than the alkaloid cations. The quantum yield of rose bengal-sensitized photooxidation of berberine and coralyne alkaloids increases significantly with pH. Singlet molecular oxygen plays an important role in the reaction mechanism.

UR - http://www.scopus.com/inward/record.url?scp=80054969582&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80054969582&partnerID=8YFLogxK

U2 - 10.1111/j.1751-1097.2011.00994.x

DO - 10.1111/j.1751-1097.2011.00994.x

M3 - Article

C2 - 21883246

AN - SCOPUS:80054969582

VL - 87

SP - 1315

EP - 1320

JO - Photochemistry and Photobiology

JF - Photochemistry and Photobiology

SN - 0031-8655

IS - 6

ER -