Ginkgo biloba from ginkgolides

These compounds were first isolated in 1932 by Furukawa [176] from the bitter principles of Ginkgo biloba, but their structures have been resolved only recently. In 1967, Nakanishi s group reported their structures and called them Ginkgolides A, B, C and M (25a,b,c,e) [177-181], These are termed BN 52020, BN 52021, BN 52022 and BN 52023, respectively, in IHB nomenclature. A new ginkgolide, J (BN 52024 25d) has been recently identified [182]. All these compounds differ only by the number and the position of hydroxy groups, which may be present on C1 C3 or C7 of the spirononane framework. 

Biber A, Koch E. (1999). Bioavailability of ginkgolides and bilobalide from extracts of Ginkgo biloba using GC/MS. Planta Med. 65(2) 192-93. 

Wada K, Sasaki K, Miura K, Yagi M, Kubota Y, Matsumoto T, Haga M. (1993). Isolation of bilobalide and ginkgolide A from Ginkgo biloba L. shorten the sleeping time induced in mice by anesthetics. Biol Pharm Bull. 16(2) 210-12. 

Figure 2 Plasma concentrations of (ng/mL) of ginkgolide B (A) from day 1 to day 6 and (B) on day 7 after oral administration of 40 and 80 mg tablets of Ginkgo biloba extract. Source From Ref 43.

Ginkgo biloba extract is prepared from the leaves of the ginkgo tree. The most common formulation is prepared by concentrating 50 parts of the crude leaf to prepare one part of extract. The active constituents in ginkgo are flavone glycosides and terpenoids (ie, ginkgolides , , C, J, and bilobalide). 

Bilobalide (40) was isolated from the leaves by Wsinges ef al. [41], and is a sesquiterpene lactone, which has a Cert-butyl group and two hydroxyl groups in its chemical structure [42]. The ginkgo terpenes described above (bilobalide and ginkgolides) seem to be unique constituents to Ginkgo biloba because they have never been found in any other plants. 

MEDICINAL CHEMISTRY OF GINKGOLIDES FROM GINKGO BILOBA... 

Braquet, P. The ginkgolides potent platelet-activating factor antagonists isolated from Ginkgo biloba L. chemistry, pharmacology and clinical applications. Drugs Future, 1987, 12 643-699. 

Raising pressure at a fixed temperature improves the extraction efficiency due to an increased fluid density. In the extraction of bilobalide and ginkgolides, the maximum extraction efficiency was achieved when the density was at least 0.72 g/mL. Because the extraction of bilobalide and ginkgolides is improved at elevated temperature, high pressures are requited to olMain the minimum needed density. At the optimal temperature (100 °C), a density of 0.72 g/mL was obtained at 350 atm pressure. With the qitimized conditions (ethanol/acetic acid as a modifier, 100 °C and 330 atm), quantitative extraction of terpene trilactones from Ig sample of Ginkgo biloba was achieved with 20 min static and 20 min dynamic extraction times (two times of SFE). Under... 

Core-modified ginkgolides, terjjene tiilactones from Ginkgo biloba extract 05H(66)743. 

CijHigOg, Mr 326.30, mp. >300°C, [a]o -64° (acetone), soluble in organic solvents, Sesquiterpene from the ginkgo tree (Ginkgo biloba). It is a C,5 trilactone, similar to the ginkgolides which are hexacyclic diter-penes and, like them, possesses the as yet only naturally occurring rert-butyl groups. For synthesis, see Lit). 

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