Gingko Biloba Treatment Shows Clinical and Genomic Safety in Older Adults

Written by Angeline A. De Leon, Staff Writer. Six months of supplementation with Ginkgoselect®Plus validated its safety as a clinical therapeutic that does not increase cancer risk in a population of older adults.

Of the many different herbal remedies used in Chinese medicine, gingko biloba is one of the oldest and also one of the most powerful ¹. The applications of gingko biloba range from respiratory disorders and sexual dysfunction to bladder infections and alcohol abuse ^2-4. Today, gingko biloba is a commercialized medicinal plant, its primary use relating to the treatment of cognitive dysfunction, particularly memory loss, in older adults ⁵. Despite its proven efficacy in treating conditions such as dementia ⁶, some research suggests that gingko biloba intake is associated with adverse effects ⁷. In a technical report published by the U.S. National Toxicology Program in 2013, investigators reported experimental evidence of potential toxicological and carcinogenic properties associated with gingko biloba, with increased rates of thyroid and liver cancer documented among rodents exposed to high doses of gingko biloba extract ⁸. Subsequent research also indicated an increased expression of genes involved in liver carcinogenesis in gingko biloba-treated mice ⁹. Although the International Agency for Research on Cancer (IARC) concluded in 2016 that evidence of carcinogenic effects associated with gingko biloba intake was insufficient in humans ¹⁰, concerns regarding the clinical safety of gingko biloba supplementation remain. Therefore, in 2018 a research group in Italy aimed to assess the clinical and genomic risks associated with gingko biloba in a population of older adults ¹¹.

A randomized, double-blind, placebo-controlled trial was carried out in a group of 47 older adults (mean age = 80.2 years) who were randomly allocated to receive 120 mg of gingko biloba leaf extract (24.3% flavone glycosides, 6.1% terpene lactones) or matching placebo twice daily for 6 months. At the beginning and end of the study period, blood samples were collected to evaluate liver injury (alanine aminotransferase, ALT; aspartate aminotransferase, AST) and genomic stability (alkaline comet assay and micronucleus assay were used to measure DNA breaks and frequency of micronuclei, containing damaged chromosome fragments). In addition, the expression profiles of three genes associated with early hepatic carcinogenesis (p53, c-myb, ctnnb1) were evaluated in a subgroup of 17 subjects.

Final results indicated the absence of any adverse clinical effects associated with gingko biloba treatment. No specific symptoms or complaints were reported in either treatment group, and no significant elevations in liver enzymes were observed for gingko biloba-treated subjects. No between-group differences were detected for micronuclei frequency (Mean Ratio = 1.01, 95% Confidence Interval: 0.86 to 1.18) or DNA breaks (MR = 0.91, 95% CI: 0.58 to 1.43). Finally, regarding expression levels of genes associated with liver carcinogenesis, no significant differences between treatment groups were detected for p53, c-myb, or ctnnb1.

Findings confirm the safety of using gingko biloba extract as a therapeutic treatment in older adults. Administration of gingko biloba over a period of 6 months was not seen to increase genomic instability or DNA damage, and no increases in the regulation of genes associated with early liver carcinogenesis were apparent. Results stand in contrast to the findings reported by the National Toxicology Program in 2013 and suggest that the therapeutic benefits of gingko biloba supplementation are not offset by an increased risk of cancer. Strengths of the current study include its randomized controlled trial design, multi-endpoint approach, and relatively long follow-up period. Its primary limitation pertains to the large number of participant dropouts during the intervention, leading to a relatively small final sample size.

Source: Bonassi S, Prinzi G, Lamonaca P, et al. Clinical and genomic safety of treatment with Gingko biloba L. leaf extract (IDN 5933/Gingkoselect®Plus) in elderly: a randomized placebo- controlled clinical trial (GiBiEx). BMC Complementary and Alternative Medicine. 2018; 18: 22. DOI: 10.1186/s12906-018-2080-5.

© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0. International License (http://creativecommons.org/licenses/by/4.0/)

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Posted October 20, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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