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Pharmacologic activity of proanthocyanidins (PACs) in Ginkgo biloba leaf extract has recently been reported. The objective of the present study was to screen the PACs content in herbal medicinal products containing Ginkgo extracts. A recently published HPLC method for quantification of PACs in Ginkgo biloba leaf extract EGb 761 was adopted to be also suitable for finished herbal medicinal products. The method was applied to 14 products from the German market. For each product a set of 3 individual batches was purchased and analyzed. Substantial differences in PACs content were found among distinct products ranging from 0.30 % to 5.86 %. The batch-to-batch variability within each product was low. The highest concentrations are in a similar range as for example the amount of Ginkgo terpene trilactones specified in the monograph for Ginkgo biloba leaf extract in the Ph. Eur.. Although it has not yet been established whether and to which extent PACs contribute to the overall pharmacological or clinical efficacy of Ginkgo extracts, a potential impact on the purported benefits of different contents in PACs cannot be ruled out. Quality assessment of different Ginkgo extracts in future may include the PACs., Competing Interests: The authors Stefan Germer and Thomas Ritter are employees of Dr. Willmar Schwabe GmbH & Co. KG. The author Mario Wurglics has received speaker’s honoraria and research grants from Dr. Willmar Schwabe GmbH & Co. KG., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

The Ginkgo extract EGb 761 ® manufactured with leaves of Ginkgo biloba has been continuously produced over decades at a large scale and is used as a clinically proven remedy for, among other things, the improvement of age-associated cognitive impairment and quality of life in patients with mild dementia. It belongs to the class of extracts addressed as quantified extracts according to the European Pharmacopeia. Accordingly, several compounds (e.g., flavone glycosides and terpene trilactones) are acknowledged to contribute to its clinical efficacy. Covering only about 30% of the mass balance, these characterized compounds are accompanied by a larger fraction of additional compounds, which might also contribute to the clinical efficacy and safety of the extract. As part of our systematic research to fully characterize the constituents of Ginkgo extract EGb 761, we focus on the structural class of proanthocyanidins in the present study. Structural insights into the proanthocyanidins present in EGb 761 and a quantitative method for their determination using HPLC are shown. The proanthocyanidins were found to be of oligomeric to polymeric structure, which yield delphinidin and cyanidin as main building blocks after acidic hydrolysis. A validated HPLC method for quantification of the anthocyanidins was developed in which delphinidin and cyanidin were detected after hydrolysis of the proanthocyanidins. The content of proanthocyanidins in Ginkgo extract EGb 761 was found to be approximately 7%., Competing Interests: All authors are employees of Dr. Willmar Schwabe GmbH & Co. KG, Germany., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commecial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Investigation of the benzopyranones from the roots of PELARGONIUM SIDOIDES led to the identification of 15 benzopyranones, among them the novel compounds 12 and 14. Furthermore, benzopyranones 4 and 15 were detected in PELARGONIUM SIDOIDES for the first time. Structure determinations were performed by one- and two-dimensional NMR spectroscopy. An HPLC system for the discrimination of these benzopyranones has been developed., (Copyright Georg Thieme Verlag KG Stuttgart New York.)

Extracts of PELARGONIUM SIDOIDES, commonly known as EPs 7630, are produced by extraction of milled roots with 11 % (w/w) ethanol in water. This solvent leads to a spectrum of constituents which differs significantly from extracts obtained by extraction with non-polar solvents. EPs 7630 is composed of six main groups of constituents, namely unsubstituted and substituted oligomeric prodelphinidins, monomeric and oligomeric carbohydrates, minerals, peptides, purine derivatives and highly substituted benzopyranones. The oligoprodelphinidins, frequently supposed to be compounds with unspecific tanning interactions, show, in contrast to other polyphenols, an amazing variety of substructures and connectivities which results in an uncommon diversity even at a low degree of polymerization. Three distinct purine derivatives, second messengers and probably intermediates of DNA synthesis, were identified and characterized by phytochemical means. The main benzopyranones of EPs 7630 are highly oxygenated at the phenyl moiety (three to four oxygens) and in addition sulfated at distinct positions. A disulfate of 6,7,8-trihydoxybenzopyranone has been identified for the first time in plants. Taken together, these constituents amount to about 70 to 80 % of the total weight of EPs 7630, the active ingredient of the phytopharmaceutical Umckaloabo (Iso Arzneimittel Ettlingen).