Furocoumarins
Furocoumarins (also furanocoumarins ) are often found in umbellifers such as hogweed ( giant hogweed , meadow hogweed ) and medicinal angelica , as well as in rhombus plants such as citrus plants (including bergamot , lemon , lime , grapefruit , bitter orange etc.) and in a number of other plants . Furocoumarins belong to the secondary plant substances and serve as phytoalexins (a type of defense substance).
properties
In the basic structure of the furocoumarins, coumarin is fused with a furan ring . Well-known furocoumarins are psoralen , bergapten and xanthotoxin . Chalepensin (xylotensin) was also found in the diamond species Ruta chalepensis .
Like most α, β-unsaturated carbonyl compounds, furocoumarins are very reactive. Furocoumarins are photoactivated when exposed to sunlight ( UVA and UVB radiation). A prominent example is the poisonous juice of the giant hogweed (Hercules shrub). The furocoumarins it contains damage the human organism in two ways:
- Photosensitizing / phototoxic : If furocoumarins get on the skin and are then exposed to sunlight (UV radiation), symptoms similar to burns occur depending on the severity(reddening of the skin, swelling, blistering, lesions, photopigmentation, scarring). See also berloque dermatitis , photodermatitis .
- Carcinogenic : Furocoumarins form covalent bonds with the pyrimidine bases of the DNA under the action of UV, thus irreversibly linking the DNA double strands with one another ( DNA crosslinking ) and thus have a carcinogenic effect.
In medicine, furocoumarins such as bergapten , trioxsalen , xanthotoxin or trimethylpsoralen are used to treat psoriasis as part of phototherapy and photochemotherapy.
Overview
Psoralen type | |||||
image | |||||
Surname | Psoralen | Bergapten | Xanthotoxin | Isopimpinellin | Empress |
R 1 | H | OCH 3 | H | OCH 3 | H |
R 2 | H | H | OCH 3 | OCH 3 | O-CH 2 -CH = C (CH 3 ) 2 |
CAS number | 66-97-7 | 484-20-8 | 298-81-7 | 482-27-9 | 482-44-0 |
PubChem | 6199 | 2355 | 4114 | 68079 | 10212 |
Molecular formula | C 11 H 6 O 3 | C 12 H 8 O 4 | C 12 H 8 O 4 | C 13 H 10 O 5 | C 16 H 14 O 4 |
Molar mass | 186.16 g mol −1 | 216.19 g mol −1 | 216.19 g mol −1 | 246.21 g mol −1 | 270.28 g mol −1 |
Angelicin type | ||||
image | ||||
Surname | Angelicin | Pimpinellin | Isobergapten | Sphondin |
R 1 | H | OCH 3 | H | OCH 3 |
R 2 | H | OCH 3 | OCH 3 | H |
CAS number | 523-50-2 | 131-12-4 | 482-48-4 | 483-66-9 |
PubChem | 10658 | 4825 | 68082 | 108104 |
Molecular formula | C 11 H 6 O 3 | C 13 H 10 O 5 | C 12 H 8 O 4 | C 12 H 8 O 4 |
Molar mass | 186.16 g mol −1 | 246.21 g mol −1 | 216.19 g mol −1 | 216.19 g mol −1 |
Occurrence in nature (selection)
Individual evidence
- ↑ RM Brooker, JN Eble, NA Starkovsky: Chalepensin, chalepin and chalepin acetate, three novel furocoumarins from Ruta chalepensis. In: Lloydia. Volume 30, 1967, p. 73.
- ↑ furanocoumarins as potent chemical defenses .
- ↑ a b Jeannette Aryee-Boi: shower PUVA: An innovative method of local PUVA therapy Clinical and pharmacokinetic results in psoriasis vulgaris. Inaugural dissertation at the Free University of Berlin, 2002.
- ↑ Oskar Schimmer: The mutagenic and carcinogenic potency of furocoumarins. In: Pharmacy in our time. Volume 10, No. 1, 1981, pp. 18-28.
- ↑ Eberhart Teuscher: Biogenic poisons. 1987, p. 233.
- ↑ Andreas Herde: Investigation of the coumarin pattern in fruits of selected Apiaceae. (PDF 2.3 MB) Dissertation University of Hamburg, 2005, p. 29 f.
- ↑ Entry on furocoumarins. In: Römpp Online . Georg Thieme Verlag, accessed on May 19, 2015.