Ginkgo biloba seeds in human diet: effect of domestic and industrial heating on ginkgotoxin content

Introduction: Gingko biloba seeds are consumed in Asian countries for their nutritional value. However, several cases of G. biloba seed poisoning have been described in literature due to the presence of the neurotoxin 4'-O-methylpyridoxine (MPN) [1]. The risk due to food containing G. biloba seeds has increased gradually in Europe, where there is a progressive diffusion of oriental cuisine. Methods: A High Performance Liquid Chromatography method coupled with fluorimetric detector (HPLC-FLD) was developed and validated in order to quantify MPN in G. biloba seeds. Samples included Japanese raw and Chinese commercial seeds present in the Italian market. The effect of different technological processes (home cooking or industrial treatment) on MPN concentration was evaluated. Results: The HPLC-FLD method was validated according to the FDA guidelines [2]: all criteria were respected. A good linearity as well as a high sensitivity were obtained, as shown by the linear coefficient (R2>0.98) and Limit of Detection and Quantitation (2.80 ng/g and 9.4 ng/g dry weight, respectively). MPN content in G. biloba raw seeds was 294.70±92.0 μg/g, according to literature data, where a range of 170-400 μg/g is reported [3]. Some of the most frequent home cooking treatments were applied and compared with commercial ones. Our preliminary results showed that only the industrial treatment reduced significantly the level of MPN (-98.8%) so that their consume can be considered safe. Among the other thermic treatments, the microwave cooking was the less effective in seed detoxification. Conclusions: Although the temperature and time of heating affected differently the MPN content, only the industrial treatment reduced significantly the toxin concentration. Further thermic treatments will be applied to G. biloba seeds, to evaluate the role of different domestic processes in reducing the ginkgotoxin content in seeds and evaluate their safety for human consumption. References 1. Hori T., Fujisawa M., Shimada K., Oda A., Katsuyama S., Wada K., Biol Pharm Bull, 27, 486-491 (2004). 2. Food and Drug Administration, Guidance for Industry – Bioanalytical Method Validation, (2013). 3. Wada K., Ishigaki S., Ueda K., Sakata M., Haga M., Chem Pharm Bull, 33, 3555-3557 (1985).