Metadata review of variation in published chemical compositions of Mentha piperita essential oils

In this review, we have sampled articles from the literature on Mentha piperita with the purpose of evaluating the magnitude of natural variation in the chemical composition of essential oils. Thus, 26 articles about Mentha piperita essential oil collected from those including complete gas chromatographic profiles and recently published, accounting for ca. 10% of total published literature on the topic, were analyzed. First of all, we found that none of the 26 reported profiles met all 12 chemical ranges set in the AFNOR standard for Mentha piperita essential oil. In terms of chemical diversity, we found 85 compounds reported only in one publication, and one single report had up to 13 single-handed. A total of 171 different compounds were described in these 26 publications, with some questionable practices in terms of identification. Beyond natural variability, the selection appeared too heterogeneous in quality and good analytical practices to account for the qualitative and quantitative diversity of results observed.