Passionflower (Passiflora incarnata): Quality of Food Supplements Versus Registered Herbal Medicinal Products

The above-ground plant material from <i>Passiflora incarnata</i> is used for relief of symptoms of mental stress and to aid sleep. In Europe, passionflower products are marketed either as registered herbal medicinal products or as food supplements. Passionflower products for sleep disorders are increasingly recommended to patients by physicians or by social advertisement, but the potential consumers are in most cases not able to differentiate between food supplements or licensed herbal medicinal products. Analytical investigations by validated protocols on passionflower food supplements and registered medicinal products from different sources were performed to obtain an insight into the actual quality situation. TLC fingerprinting revealed the non-identity of five food supplements, while six products met the specification (five registered herbal medicinal products and one food supplement). A validated UHPLC method confirmed this result. LC-MS identified one food supplement containing only hyperoside and lacking other passionflower-related compounds. Quantitative determination of flavones by photometric protocol, as well as by a calibrated UHPLC, indicated that five out of six food supplements did not meet the specified content and identity, suggesting instances of food fraud. All registered herbal medicinal products conformed to the specification. As this analytical investigation is in line with other reports on the low quality of food supplements, transparent and intensified quality control is recommended. In addition, routine analyses of every batch using validated procedures by manufacturers on a batch-by-batch basis should provide a secure basis for improved product quality and for the safety of the consumer.