Прекаленото количество гинколова киселина причинява тежки кожни алергии
В Германия, Франция, Австрия и Холандия продуктите Гинко Билова не могат да съдържат повече от 0,0005% (5 ppm) гинколова киселина
Ginkgolic acid-rich Ginkgo biloba product causes serious allergic skin reactions !
Ginkgo extracts registered in Germany are not allowed to contain more than 5 ppm (0.0005
%) ginkgolic acids. The German Pharmacopoeia and the Commission E monograph indicate
this limit value which is also valid in other countries such as e.g. France, Austria and the
Netherlands. In its Ginkgo monograph, the World Health Organization (WHO) also requires
adherence to this maximum value.
Chemically ginkgolic acids belong to the alkylphenol group. Among these compounds are a
large number of allergy-inducing plant constituents such as e.g. urushiols from toxicodendron
types or anacardic acids from the seed coat of cashew nuts. Recent results from research
showed that alkylphenols and in particular ginkgolic acids additionally have properties
causing toxic effects on cells, damaging the genetic constitution (induction of DNA-strand
breaks) and promoting cell growth (tumor promotion). The limit value of 5 ppm was chosen
since it complies with the detection limit recordable by routine methods, thus allowing to
assure to a maximum degree removal of these compounds from therapeutically used
In the USA and other countries in which Ginkgo preparations are sold as food supplement,
such binding limit values do not exist. For this reason, it is certainly not surprising to read in a
reputed American specialist journal (Chiu A.E. et al., J. Am. Acad. Dermatol. 46, 2002, 145-146) a report on serious allergic skin reactions in a patient who had taken a non monographconform Ginkgo product. A 66-year-old woman presented with a measles-like eruption
covering most of her body and pin-point red spots caused by intradermal bleeding
developing on her legs after she had taken for one week a Ginkgo dietary supplement sold in
the USA. The authors stress the high allergy-inducing risk related with the ingestion of
Ginkgo products which do not comply with the limit value for ginkgolic acids.
A series of investigations conducted by the company Schwabe and an independent
university laboratory on 10 different batches of the Ginkgo product involved, showed that it
contained concentrations of ginkgolic acids that generally exceeded the permissible limit
value by a factor greater than 100 (!). Similarly disillusioning test results were obtained by the
Hong Kong Consumer Council. The analysis of 14 different Ginkgo preparations showed that
in 13 products levels of ginkgolic acid ranged from 16 to 733 times more than the
recommendation by the WHO (http://www.consumer.org.hk/p289e.htm).
Of course, the Ginkgo special extract EGb 761 manufactured by the company Schwabe
complies with the requirements of the German Pharmacopoeia, the commission E and the
WHO. Because of the health-damaging properties of ginkgolic acids and as demonstrated
impressively by this recently published case, it is urgently recommended not to take ginkgolic
acid-containing products of poor quality.