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Effect of light on hypericins contents in fresh flowering top parts and in an extract of St. John's Wort (Hypericum perforatum).
Planta Med. 2001 Apr; 67(3):254-9.PM

Abstract

St. John's Wort is a medicinal plant increasingly used for its antidepressive activity. Hypericins are considered as one of the compounds contributing to the activity of the extract. These naphthodianthrones exist in various forms in Hyperici herba. Protopseudohypericin and protohypericin (protopigments) are converted into pseudohypericin and hypericin (pigments) under the action of light. The aim of this work is to study the influence of light on the phototransformation of protopigments into pigments. Two experiments were carried out. The studies were performed on one hand, on plant material in order to know the proportion of these substances in various plant parts and the possibility of transforming the protopigments into pigments under the action of sunlight; on the other hand, in the extract to determine the optimal wavelength allowing this transformation. Three parts of the fresh plant (buds, flowers, leaves) were treated with sunlight on three levels of exposure. Liquid extracts were exposed to various types of light with wavelengths ranging between 480 and 660 nm by means of diodes. The flowering tops of St. John's Wort contain a share of approximately 30% hypericins in the form of protopseudohypericin and protohypericin: buds (48%), flowers (30%), leaves (17%). After an exposure of fresh buds to sunlight for 16 hours the share of protopigments was then 32%. In the extract, the transformation of the protopigments is total and requires less energy than in the plant material. The optimal wavelength for the transformation of the protopigments in the extract is around 515 nm (green), close to the optimum absorption level of protopigments.

Authors+Show Affiliations

National Institute of Agronomic Research, Colmar, France. poutarau@colmar.inra.frNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

11345698

Citation

Poutaraud, A, et al. "Effect of Light On Hypericins Contents in Fresh Flowering Top Parts and in an Extract of St. John's Wort (Hypericum Perforatum)." Planta Medica, vol. 67, no. 3, 2001, pp. 254-9.
Poutaraud A, Di Gregorio F, Tin VC, et al. Effect of light on hypericins contents in fresh flowering top parts and in an extract of St. John's Wort (Hypericum perforatum). Planta Med. 2001;67(3):254-9.
Poutaraud, A., Di Gregorio, F., Tin, V. C., & Girardin, P. (2001). Effect of light on hypericins contents in fresh flowering top parts and in an extract of St. John's Wort (Hypericum perforatum). Planta Medica, 67(3), 254-9.
Poutaraud A, et al. Effect of Light On Hypericins Contents in Fresh Flowering Top Parts and in an Extract of St. John's Wort (Hypericum Perforatum). Planta Med. 2001;67(3):254-9. PubMed PMID: 11345698.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of light on hypericins contents in fresh flowering top parts and in an extract of St. John's Wort (Hypericum perforatum). AU - Poutaraud,A, AU - Di Gregorio,F, AU - Tin,V C, AU - Girardin,P, PY - 2001/5/11/pubmed PY - 2001/7/28/medline PY - 2001/5/11/entrez SP - 254 EP - 9 JF - Planta medica JO - Planta Med. VL - 67 IS - 3 N2 - St. John's Wort is a medicinal plant increasingly used for its antidepressive activity. Hypericins are considered as one of the compounds contributing to the activity of the extract. These naphthodianthrones exist in various forms in Hyperici herba. Protopseudohypericin and protohypericin (protopigments) are converted into pseudohypericin and hypericin (pigments) under the action of light. The aim of this work is to study the influence of light on the phototransformation of protopigments into pigments. Two experiments were carried out. The studies were performed on one hand, on plant material in order to know the proportion of these substances in various plant parts and the possibility of transforming the protopigments into pigments under the action of sunlight; on the other hand, in the extract to determine the optimal wavelength allowing this transformation. Three parts of the fresh plant (buds, flowers, leaves) were treated with sunlight on three levels of exposure. Liquid extracts were exposed to various types of light with wavelengths ranging between 480 and 660 nm by means of diodes. The flowering tops of St. John's Wort contain a share of approximately 30% hypericins in the form of protopseudohypericin and protohypericin: buds (48%), flowers (30%), leaves (17%). After an exposure of fresh buds to sunlight for 16 hours the share of protopigments was then 32%. In the extract, the transformation of the protopigments is total and requires less energy than in the plant material. The optimal wavelength for the transformation of the protopigments in the extract is around 515 nm (green), close to the optimum absorption level of protopigments. SN - 0032-0943 UR - https://www.unboundmedicine.com/medline/citation/11345698/Effect_of_light_on_hypericins_contents_in_fresh_flowering_top_parts_and_in_an_extract_of_St__John's_Wort__Hypericum_perforatum__ L2 - http://www.thieme-connect.com/DOI/DOI?10.1055/s-2001-12003 DB - PRIME DP - Unbound Medicine ER -