Pyrrolizidine alkaloid contents and profiles in Borago officinalis leaves, flowers and microgreens: Implications for safety

Abstract

Borago officinalis (borage) is widely consumed as a herb or vegetable, however, it produces toxic pyrrolizidine alkaloids (PA). In 2020, the European Union (EU) established maximum levels for the PA content in certain foodstuffs, including borage leaves. This study aimed to evaluate PA contents and profiles in borage originating from different cultivation conditions and developmental stages. A total of 106 borage leaf samples, including borage microgreens, leaves from commercial producers, and plants from various home gardens at pre-flowering, flowering and end-of-flower stages, as well as 33 flower samples from plants grown in home gardens, were analyzed. The microgreens exhibited strikingly high PA contents, exceeding the maximum level set by Commission Regulation (EU) 2023/915 by an average factor of 130. PA contents in the leaves of pre-flowering plants exceeded the maximum level by an average factor of 5, whereas PA contents in the leaves of flowering plants were below the maximum level in most cases. The PA contents in flowers were higher than those of the corresponding leaves, suggesting increased accumulation of PA in flowers compared to leaves. Additionally, the occurrence of acetylated PA, especially 7-acetyl-lycopsamine-N-oxide, which are not listed in the EU regulation, was shown to be significant in borage. In summary, our results indicate that the PA contents in borage leaves are highest in emerging plants and decrease with the progression of plant or leaf maturity. The findings suggest that borage microgreens may not be suitable for human consumption and that further regulatory consideration of acetylated PA is warranted.