The authors try to re-evaluate the role of microsomal epoxide hydrolase (mEH) as 2-AG hydrolase, which has been previously published. They present the hypothesis of a contamination being the cause of the results already published, and therefore a better purification could help to solve the controversy.
Publishing contradictory results is very useful for the advancement of Science. This can save time and money to others trying to replicate the original results or basing their experiments on data that can be proved later to be wrong.
However, their claims are not supported by the data presented here. They need to show all the data they have collected (Coomassie stained gel, HPLC-MS chromatograms) if they want to convince the readers that their experiments have been done properly and are therefore more reliable than the previously published. Instead, they present only a bar graph, without the raw data behind it.