• Phytotherapy

Ginkgo special extract with patented production process

Ginkgo biloba (G. biloba) is one of the best-studied medicinal plants in phytotherapy. Extracts from G. biloba leavesare used in medicine to treat cognitive impairment, dizziness and tinnitus. In a review published in 2022, the product-by-process conceptof a G. biloba special extractrecommended in national and international guidelines for the treatment of dementia is examined. The pharmacologically relevant ingredients (especially flavonoids and ginkgolipids) are extracted and prepared in a complex standardized production process.

Ginkgo biloba (G. biloba) is a medicinal plant with a long tradition. There are numerous different methods for extracting G. biloba leaves. Extracts obtained from one and the same plant can have very different phytochemical compositions [1]. This should be borne in mind when interpreting pharmacological, toxicological and clinical studies carried out with extracts produced using different manufacturing processes. The medically important substances of EGb 761® (trade name CH: Tebokan®) include flavonol glycosides, ginkgolides and bilobalide as well as other valuable active ingredients (e.g. delphinidin and cyanidin) [1,3]. EGb 761® is one of the G. biloba preparations that meets the high requirements of the monograph published by the Committee on Herbal Medicinal Products (HMPC) of the European Medicines Agency (EMA) [2]. In addition, the flavonol glycosides and terpene lactones (ginkgolides and bilobalide) contained in the special extract EGb 761® were detected in animal models in relevant concentrations in the hippocampus, striatum, frontal and cerebellum, which indicates good bioavailability [15, 16].

The special ginkgo extract EGb 761® (trade name CH: Tebokan®) is considered to be one of the best-studied plant extracts in the world. A PubMed search for EGb 761® results in over 2000 articles** and EGb 761® was described as “the most studied extract in clinical research” [9]. EGb 761® has been shown to improve microcirculation and blood flow properties both in animal experiments and in humans [3]. EGb 761® is approved by health insurance companies in Switzerland for the symptomatic treatment of impaired mental performance [3].
** As of July 2022

EGb 761® results from a unique extraction process

In the review published in the journal Frontiers in Pharmacology by Kulić et al. explains in detail how the region of cultivation, further processing of the plant material, the drying process, the extraction process and details of the subsequent production steps influence the quality and the degree of standardization of the high-quality end product EGb 761® [1]. Particular attention is paid to the regulation of the active ingredient content and the consistent reduction of undesirable substances in plant extracts. This is ensured by a controlled manufacturing process and corresponding analytical specifications [1]. EGb 761® is extracted from the leaves of the G. biloba tree in a complex process. The plant material used for production comes from three different continents: Asia (China), North America (USA) and Europe (France) [4]. Here, the plant-based starting material is not simply ground and mixed with a solvent, but rather a number of refinement steps follow the initial extraction – a complex, time-consuming process that lasts for many days and is monitored for quality [1]. Around 110 different flavonoids have been identified in the leaves of G. biloba [5].

EGb 761® for the treatment of dementia
In the current German guideline on dementia treatment, G. biloba extractEGb 761® is specifically recommended with the highest level of evidence for the treatment of mild to moderate dementia$ [10]. EGb 761® is also mentioned as an evidence-based treatment option in the guidelines of the World Federation of Societies of Biological Psychiatry and the Swiss guidelines for the diagnosis and treatment of behavioral and psychological symptoms in dementia [11,12]. The neuroprotective effects can be explained, among other things, by an improvement in blood flow in the area of the small vessels and an increased oxygen supply to the cells [13,14].
$ vascular dementia or Alzheimer’s dementia

Depending on the extraction process (e.g. polarity of the solvents used), the individual flavonoid glycosides may be present in different proportions. Most extraction processes are aimed at enriching flavonol glycosides, terpene trilactones or other beneficial components, while the ginkgolic acids in the final product are decimated. For this purpose, the liquid primary extract must be processed in further steps in order to break down the phytochemicals into the desired product [6]. The extract EGb 761® is described in the literature by independent research groups as the “gold standard”, as it consistently meets the specifications of previous and current pharmacopoeias [7].

Flavonoids are a group of secondary plant substances that are said to have antioxidant properties. In addition to flavonol glycosides, terpene lactones and other components, the flavonoids contained in EGb 761® also include proanthocyanidins (PACs). Due to heterogeneous production processes, the content of PACs in ginkgo products from different manufacturers can vary considerably. PACs make up about 4-19% of EGb 761®, with a high consistency from batch to batch (Table 1) [8].

Literature:

  1. Kulić Ž, Lehner MD, Dietz GPH: Ginkgo biloba leaf extract EGb 761® as a paragon of the product by process concept. Front Pharmacol. 2022; 13: 1007746. Published 2022 Oct 11.
  2. European Union herbal monograph on Ginkgo biloba L., folium, EMA/HMPC/321097/2012, 28.01.2015.
  3. Swissmedic: Medicinal product information, www.swissmedicinfo.ch,(last accessed 07.05.2024)
  4. Schmid W, Balz JP: Cultivation of Ginkgo biloba L. On three continents. Acta Hortic 2005; 676: 177-180.
  5. Liu L, et al: Advances in the chemical constituents and chemical analysis of Ginkgo biloba leaf, extract, and phytopharmaceuticals. J Pharm Biomed Anal 2021; 193: 113704.
  6. Boateng I D: A critical review of ginkgolic acid in Ginkgo biloba leaves extract (egb). Toxicity, technologies to remove the ginkgolic acids and its promising bioactivities. Netherlands: Food & Function, 2022.
  7. Wohlmuth H, et al: Adulteration of Ginkgo biloba products and a simple method to improve its detection. Phytomedicine 2014; 21, 912-918.
  8. Kulić Ž, et al: A detailed view on the proanthocyanidins in Ginkgo extract EGb 761®. Planta Med 2021b; 88, 398-404.
  9. Martinez-Solis I, et al: Neuroprotective potential of Ginkgo biloba in retinal diseases. Planta Med 2019; 85, 1292-1303.
  10. Deuschl G, Maier W: S3-Guideline Dementia, in: DGN (ed.): Diagnostik und Therapie in der Neurologie. 2016, www.dgn.org,(last accessed 07.05.2024)
  11. Ihl R, et al: World federation of Societies of biological Psychiatry guidelines for the pharmacological treatment of dementias in primary care. Int J Psychiatry Clin Pract 2015; 19: 2-7.
  12. Savaskan E, et al: Recommendations for the diagnosis and treatment of the behavioral and psychological symptoms of dementia. Practice 2014; 103, 737-738.
  13. EMA: www.ema.europa.eu/en/documents/herbal-summary/ginkgo-leaf-summary-public_de.pdf,(last accessed 07.05.2024)
  14. Pharmawiki: www.pharmawiki.ch/wiki,(last accessed 07.05.2024).
  15. Ude C, et al: Plasma and brain levels of terpene trilactones in rats after an oral single dose of standardized Ginkgo biloba extract EGb 761(R). Planta medica 2011; 77: 259-264.
  16. Rangel-Ordóñez L, et al: Plasma levels and distribution of flavonoids in rat brain after single and repeated doses of standardized Ginkgo biloba extract EGb 761®. Planta medica 2010; 15: 1683-1690.

FAMILY PHYSICIAN PRACTICE 2024; 19(5): 28-29

Autoren
  • Mirjam Peter, M.Sc.
Publikation
  • HAUSARZT PRAXIS
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