Ginkgolide

Ginkgo tree ( Ginkgo biloba )

Ginkgo leaves in close-up

Ginkgolide are hexacyclic terpenes with three γ- lactone rings, 2-3 hydroxy and one tert. -Butyl group. So far, five representatives of the substance group are known (ginkgolid A, B, C, J, M). The tert- butyl group has so far only been detected in extracts from ginkgo leaves. So also in the ginkgolides in its constitution closely related bilobalide .

biosynthesis

Nakanishi was able to show that the ginkgo tree incorporates radioactive ¹⁴ C from the labeled compounds sodium acetate , mevalonic acid and methionine into ginkgolides. This provided proof of the terpenoid origin of the polycyclic hydroxylactones from Ginkgo biloba. The exact biosynthesis has not yet been clarified in detail.

Occurrence

In 1967 Sakabe and Masao Maruyama isolated hydroxylactones of unknown constitution for the first time from Ginkgo biloba extracts. The elucidation of the structures by Weinges and others lasted until the end of the 20th century.

Structures

Ginkgolide and their substitution pattern
Ginkgolide	R ¹	R ²	R ³	CAS
Ginkgolide A	−H	−OH	−H	15291-75-5
Ginkgolide B	−H	−OH	−OH	15291-77-7
Ginkgolide C	−OH	−OH	−OH	15291-76-6
Ginkgolide J.	−OH	−OH	−H	15291-79-9
Ginkgolide M.	−OH	−OH	−H	15291-78-8

use

In addition to flavonoids, ginkgolides are the ingredients of ginkgo preparations that determine the effectiveness .

Web links

Commons : Ginkgolides - collection of images, videos and audio files

Individual evidence

↑ K. Nakanishi et al .: J. Am. Chem. Soc. 1971 , 93; P. 3546.
↑ Sakabe, N. et al .: J. Chem. Soc., Chem. Commun. 1967 ; 259.
↑ Maruyama, M. et al. Tetrahedron Lett. 1967 ; 299
^ Weinges, K. et al .: Justus Liebigs Ann. Chem 1986 ; 1057, structure & partial synthesis of ginkgolide B & C.
↑ Weinges, K. et al .: ibid 1987 ; 521, Ginkgolid J.
↑ Weinges, K. et al .: ibid 1991 ; 81, structure & partial synthesis.
↑ Crimmins, MT et al .: J. Am. Chem. Soc. 2000 ; 8453, synthesis of ginkgolide B.
↑ Rudolf Hänsel, Otto Sticher (ed.): Pharmakognosie. Phytopharmacy . 9th edition, Springer Medizin Verlag, Heidelberg 2009, ISBN 978-3-642-00962-4 , p. 1134.

[1] K. Nakanishi et al .: J. Am. Chem. Soc. 1971 , 93; P. 3546.

[2] Sakabe, N. et al .: J. Chem. Soc., Chem. Commun. 1967 ; 259.

[3] Maruyama, M. et al. Tetrahedron Lett. 1967 ; 299

[4] Weinges, K. et al .: Justus Liebigs Ann. Chem 1986 ; 1057, structure & partial synthesis of ginkgolide B & C.

[5] Weinges, K. et al .: ibid 1987 ; 521, Ginkgolid J.

[6] Weinges, K. et al .: ibid 1991 ; 81, structure & partial synthesis.

[7] Crimmins, MT et al .: J. Am. Chem. Soc. 2000 ; 8453, synthesis of ginkgolide B.

[8] Rudolf Hänsel, Otto Sticher (ed.): Pharmakognosie. Phytopharmacy . 9th edition, Springer Medizin Verlag, Heidelberg 2009, ISBN 978-3-642-00962-4 , p. 1134.