The American Herbal Products Association (AHPA) today disputed the results of a National Toxicology Program (NTP) report on the supposed carcinogenicity of ginkgo (Ginkgo biloba) because the extract used in the study was not chemically similar to products sold for commercial use.

The report, “NTP Technical Report on the Toxicology and Carcinogenesis Studies of Ginkgo biloba Extract in Rats and Mice,” studied the effects of a unique ginkgo leaf extract on rats and mice to identify potential toxic or cancer-related hazards.

However, in comments made during a review of the draft report in February 2012, Steven Dentali, Ph.D., AHPA's chief science officer, presented a data table that compared the NTP gingko extract to published analyses of commercially available ginkgo products and to recognized pharmacopoeial ginkgo standards, highlighting the unique, uncommon identity of the NTP ginkgo extract. Dr. Dentali's recommendations that the final report make clear these differences in chemical composition and amended to include the word "specific" to properly qualify the test material to avoid confusion with ginkgo products sold commercially in the United States were not incorporated by NTP.

"I'm disappointed that NTP did not adopt AHPA's recommendations to properly qualify the extract that was studied and its relevance to consumers and the marketplace," said Dr. Dentali. "This is in spite of the fact that two of NTP's own peer reviewers agreed with my suggestion to include the data table showing the constituent ratios of the NTP unique test material versus readily available consumer ginkgo products. The assertions and conclusions in the final NTP report are not necessarily relevant to other commercially available ginkgo products."

A synopsis of AHPA's comments to NTP regarding the draft report and the data table created by Dr. Dentali can be found at the AHPA website. Additionally, the documents submitted to NTP by AHPA in response to the draft report, including the AHPA Analysis of the specific Ginkgo biloba extract used in NTP TR 578 and related documents, can be found on the NTP website.