The Acorn Honey Used for a Published Study was Mistakenly Listed as Quercus pyrenaica and Should Be Corrected to Quercus species

A critical review letter ¹ was published concerning the article “Quercus pyrenaica honeydew honey effects on gastric adenocarcinoma cells” published in Integrative Cancer Therapies in 2019. ² According to the letter, the authors reported that the Quercus pyrenaica mentioned in the study was neither found in Mount Ida nor within the borders of Turkey as stated in the study, therefore the results obtained in the study may belong to another Quercus species.

In fact, within the scope of this project, 14 different types of honey obtained from different regions of Turkey were studied. The total phenol and flavonoid contents of each were analyzed. According to the results, 2 honey species with the highest and lowest phenolic content were selected to research other biological activities on cancer cells. One of them was acorn honey which was obtained from Mount Ida, and the other one is a multifloral honey which was obtained from the same region. At that time, unfortunately, we did not have the opportunity to investigate the flora of the region where each honey was produced in detail. When verbally asked about the origin of acorn honey to the producer, they reported that the origin of honey is Quercus pyrenaica. Therefore, this genus was mentioned as Quercus pyrenaica in the article. In fact, our main aim with this study was to compare the total phenolic and flavonoid contents of different honey samples and their cytotoxic, genotoxic, apoptotic, and pro-oxidant activities on cancer cells. Therefore, we focused on the phenolic compounds and biological activities of the honeys rather than the flora of the region where the honeys are produced. After the letter, we focused on the flora of the region where the acorn honey is produced. The genus Quercus, with high diversity and number of species, dominates many regions of temperate, tropical, and subtropical forests of Europe and North America. ³ The genus contains more than 500 species distributed in the temperate zone in the Northern Hemisphere. ⁴ Turkey is among the richest countries in the number of Quercus taxa, with 18 species belonging to 3 sections, Quercus, Cerris, and Ile, ⁵ and 11 of them are known to be distributed in the Mount Ida region. ⁵ When we asked the Forest Regional Directorate of the region where honey is produced with an official letter, they replied that there are 3 different Quercus species, Quercus frainetto, Quercus cerris, and Quercus petraea in the region where honey is produced (letter available from the authors on reasonable request).

In conclusion, our main focus with this study was to investigate the phenolic contents of honeys and the effects of honey with the highest and lowest phenolic content on the genotoxic, cytotoxic, apoptotic, and reactive oxygen species (ROS) production capacities on cancer cells, rather than the characteristics of the flora from which 14 different honey species are produced. Information on the origin of the honey with the highest phenolic content was requested from the producer, and according to the response received, it was incorrectly mentioned as Quercus pyrenaica in the article. Therefore, we think that it would be appropriate to publish a corrigendum to correct the errors in our article.