Towards Botanical Authentication of Ginkgo Food Supplements: A Holistic Approach Based on Phytochemical and Genomic Markers

<i>Ginkgo biloba</i> is one of the most consumed medicinal plants and broadly included as an ingredient in plant food supplements (PFS) and herbal infusions, being potential targets for economically motivated adulteration. This work aimed at comparing the use of DNA and phytochemical markers to authenticate the botanical origin of ginkgo-leaf extracts and PFS. Quantitative real-time PCR was used to detect ginkgo DNA, while ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS) determined its main phytochemicals (terpene lactones and flavonol aglycones). DNA was detected in all ginkgo leaf extracts, mainly water, while the highest levels of phytochemicals were obtained using ethanol or acetone as solvents. The results suggested that 4 out of a total of 19 PFS samples were adulterated, with two samples evidencing the addition of quercetin from sources other than ginkgo. The other two samples showed low amounts of ginkgo phytochemicals, which was corroborated by low DNA content, suggesting the use of reduced amounts of <i>G. biloba</i> leaf material.