[Food Poisoning by Ginkgo Seeds through Vitamin B6 Depletion].

Overconsumption of Ginkgo biloba seeds induces food poisoning characterized by tonic-clonic convulsions and vomiting. The primary toxic component, 4'-O-methylpyridoxine (MPN), was purified from the seeds in 1985. This review includes the following aspects of ginkgo seed poisoning: 1) toxicity related to the content of MPN and MPN glucoside in G. biloba seeds; 2) the effect of MPN on vitamin B6 analogs, including an increase in pyridoxal and pyridoxic acid and decrease in pyridoxal-5'-phosphate plasma concentrations; 3) case reports of ginkgo seed poisoning in Asia, North America, and Europe, and their effective treatment via vitamin B6 administration. Considering the increase in the use of G. biloba seeds, it is essential to raise global awareness of their potential toxicity.

Ginkgo nut intoxication in a 2-year-old male.

This report describes a case of ginkgo nut intoxication in a 2-year-old male. The patient presented with vomiting and afebrile convulsion 4 hours after eating a large number of roasted gingko nuts. There was a large volume of ginkgo nuts in his vomited matter, and on admission the concentrations of 4-O-methoxypyridoxine in his serum and urine were elevated. The patient was diagnosed as having ginkgo nut intoxication, and diazepam and pyridoxal phosphate were administered intravenously. After the treatment, his symptoms were resolved. The neurotoxicity of ginkgo nuts should be recognized by pediatricians and parents who have infants.

Rapid analysis of 4-O-methylpyridoxine in the serum of patients with Ginkgo biloba seed poisoning by ion-pair high-performance liquid chromatography.

We have established a new method of HPLC analysis for the rapid separation from human serum and the quantification of 4-O-methylpyridoxine (MPN), which is contained in Ginkgo biloba seeds, and which, when consumed in large amounts, causes vomiting and convulsions. As a result of using IPCC-MS3 (GL Science, Tokyo, Japan), an ion-pair reagent, in the mobile phase, we succeeded in separating MPN in the deproteinized serum sample which was introduced directly onto the reverse-phase HPLC column. For the calibration curve of MPN standard solution, prepared with fluorescence detection at an excitation wavelength of 290 nm and an emission wavelength of 400 nm, a good linear relationship was obtained within the HPLC injection range of 10 ng-10 pg (in terms of the injected sample concentration, range: 1.0 microg/ml-1 ng/ml), allowing the detection of minute amounts, with the limit of detection (concentration of injected sample: 500 pg/ml) being 5 pg. In addition, when MPN solution was added to human reference serum to give a concentration of 0.002 microg/ml, the mean recovery rate was 92.5%, with RSD=7.09% (n=5). The time required for one analysis using this method is approximately 30 min, and thus it offers the advantages of greater speed and superior analytical sensitivity over the conventional methods, which require solid-phase extraction. We employed our new method to determine both the serum levels of MPN in 5 patients with Ginkgo biloba seed poisoning and the levels of free-form MPN in such seeds obtained in 8 regions of Japan.

Gas chromatography-mass spectrometry analysis of 4-O-methylpyridoxine (MPN) in the serum of patients with ginkgo seed poisoning.

The 4-O-methylpyridoxine (MPN) present in the seeds of the Ginkgo biloba (maidenhair tree) has anti-vitamin B6 actions, and ginkgo seed poisoning can induce convulsions. We developed a specific quantitative method using gas chromatography-mass spectrometry for the analysis of MPN in human serum. The trifluoroacyl (TFA) derivative of MPN was obtained by treating MPN with trifluoroacetic anhydride at 50 degrees C for 5 min and remained stable for 6 h. The calibration curve of standard MPN obtained in the selective ion mode using the base ion (m/z 343) was linear between 100 pg and 10 ng, and the detection limit was 50 pg. The full mass spectrum of 100 pg of the TFA derivative of MPN was obtained easily. MPN was extracted from the serum with the use of a C18 solid-phase extraction cartridge. The recovery rate of MPN added to the serum at a concentration of 0.1 microg/mL was 90.0%.

Ginkgo seed poisoning.

A 2-year-old girl presented with vomiting and diarrhea 7 hours after eating a large quantity of ginkgo seeds. She exhibited an afebrile convulsion 9 hours after ingestion. The serum concentration of 4-metoxypyridoxine was as high as 360 ng/mL. Although reported cases of ginkgo seed poisoning usually involve children who exhibit repetitive seizures that can be fatal, prompt administration of pyridoxal phosphate (2 mg/kg) may have prevented additional seizures. This is the first English-language case report measuring 4-metoxypyridoxine concentration during ginkgo seed poisoning. Awareness of the potential danger of overconsumption of this traditional food and its prompt treatment with pyridoxal phosphate may hasten recovery.