Herbal Monograph
Herb; Ginkgo (Ginkgo Biloba; Coniferales)
Distinctions between Green and Gold Leafs
Active Constituents: Flavonoids: incl. monosides, biosides and triosides of quercetin, isorhamnetins, 3′-O-methylmyristicins, kaempferol, to some extent estered with p-cumaric acid; Bioflavonoids: incl. ametoflavone, bilobetin, 5-methoxybilobetin, ginkgetin, isoginkgetin; Proanthocyanidins; Trilactonic diterpenes: ginkgolide A, B, C; Trilactonic sesquiterpenes (bilabolide). (2)
Flavone glycosides (including ginkgolide), bioflavones, sitosterol, lactones, anthocyanin (15)
The principal constituents found in a leaf extract are three flavone glycosides (quercetin, isorhamnetin and luteolin) and bioflavones (ginkgetin, isoginkgetin and bilobetin). In addition the leaves contain two lactones, sitosterol and an anthocyanin. As in the case of crataegus and many other medicinal plants, a mixture of active principles is present, with flavonoids predominating. (16)
Synopsis:
Green leaf – high in ginkgolides and bilobalides (improves circulation to brain
Gold leaf – high in flavonoids and proanthocyanidins (toning effect on blood vessels)
Levels of active principles differ in yellow/gold leaves, as compared to pre-autumn green leaves; in the gold, the anti-oxidant flavonoids reach their highest levels, but the ginkgolides and bilobalides reach highest levels just before the color change, and drop off to lowest levels when the leaves have turned yellow and are falling from the tree (cf. Cayuga Botanicals R.D. note, below, in Actions). (63)
Flavonoids act as free radical scavengers. Both free radical formation and PAF can disrupt vascular membranes, resulting in increased vascular permeability. (64)
Cayuga Botanicals R.D. Note: [The flavonoids and proanthocyanidins have a toning effect on blood vessels, whereas the ginkgolides alleviate peripheral arterial occlusion (via a blood-thinning effect), improving circulation in the brain (and elsewhere) with resultant effects on concentration and memory. Yet the ginkgolides also inhibit platelet aggregation, which can exacerbate bleeding disorders. Therefore, given the variation in the levels of these respective principles in pre- and post- autumn leaves, harvesting practices should reflect their desired use. For patients with bleeding disorders or currently taking anti-thrombotic or similar medications, whose side effects can be exacerbated by the PAF-inhibiting principle in ginkgo leaf, extracts should be from leaves harvested late; also for maximum effectiveness in treatment of varicose veins or other vascular disorders. On the other hand, if there is little danger of resulting bleeding disorder, the pre-autumn leaves are most effective for improving cognitive brain functions.
Therefore, Cayuga Botanicals utilizes green-leaf ginkgo in Brain Tonic and golf-leaf ginkgo in Circulation Tonic]–note derived largely from (63).
Cayuga Botanicalsl Monograph…footnotes
(2) PDR for Herbal Medicines (Medical Economics Co., 1998), pgs. 871-72
(15) The Complete Medicinal Herbal by Penelope Ody, pgs. 64, 151
(16) Herbal Medicine by Rudolf Weiss, M.D., pgs. 178-179
(63) Ginkgo, Elixir of Youth by Christopher Hobbs, p. 56
(64) Ginkgo Biloba, The Amazing 200-Million Year-Old Healer by Frank Murray, p. 12
PHOTO: Wikipedia