Ginkgo leaves

For centuries, the beneficial effects of crude extracts from the ginkgo tree were well known in China and India. In traditional Chinese medicine, a boiled-down extract of ginkgo leaves is inhaled to alleviate asthmatic symptoms, and, in India, ginkgo extracts constitute a key ingredient of Soma, a mystical liquid that is thought to increase life span.5 The Japanese know it as the Itcho tree and they frequently use its edible fruit, the ginkgo nut, in cooking. 

SC-CO2 was reported for the extraction of sitosterol from dandelion leaves (Simandi and others 2002) flavonoids from ginkgo leaves (Chiu and others 2002) and alkaloids from mate tea leaves (Saldana and others 1999,2000, 2002a). 

Ibataet id. [52] isolated long-chain betulaprenol-type polyprenols containing 14 to 22 isoprene units (41) from the ginkgo leaves and determined their structures by mass spectroscopy, H-... 

NMR and 13C-NMR. The concentrations of these polyprenols increased from 0.04 to 2.0% of dry weight with maturation of the leaves. A supercritical fluid chromatographic procedure for the quantitation of polyprenols in the ginkgo leaves was developed by Huh ef al. [53]. 

Hydroxykynurenic add was isolated from ginkgo leaves the first time it was found in a gymnosperm. The content reached a maximum value of 0.24% in autumn [54]. 

Traditional Chinese physicians used ginkgo leaves to treat asthma and chilblains. Today, G. biloba is used to improve both blood flow to the brain and peripheral circulation (see Chapter 36). 

The SFE technique was compared to the boiling liquid methods performed with the following solvents 1) acetone, 2) ethanol, 3) methanol, 4) water, and 5) water/methanol (70 30 vfv). The SFE method showed the highest extraction efficiency and reproducibility (RSD<5%, n = 3) for removing terpene trilactones from the ginkgo leaves in comparison with the solvent extraction methods. The total efficiencies for recovety of bilobalide and gingkolides (A, B, and C) with the solvent based methods were 60 91% relative to the SFE results (Table I). 

Figure 1 Structures of flavon- and flavonol aglycons found in leaves of Ginkgo biloba (A). Structures of some flavonol glycoside esters with coumaric acid, distinctive compounds of Ginkgo biloba (B). The coumaroyl esters of the quercetin-rhamnoglucoside and of the kaempferol-rhamnoglucoside are most common in Ginkgo leaves.

Ginkgo biloba L. Ginkgo Leaves Dementia, cognitive impairment, mental fatigue Tetpene trilactones (ginkgolides), flavonol glycosides... 

Figure 1 Relevant parts of 200 MHz NMR spectra of (A) a sample of ginkgo leaves and (B) a sample of a pharmaceutical product. Solvent acetone-d6-pyridine-d5-methanol-d4 (18 6 1) internal standard maleic acid 128 scans. (Reproduced with permission from van Beek TA, von Veldhuzen A, Lelyveld QP, Piron I, and Lankhorst PP (1993) Phytochemical Analysis 4 261-268 Wiley.)...

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