Commercial peppermint (Mentha x piperita L.) teas: Antichlamydial effect and polyphenolic composition

The qualitative and quantitative polyphenolic contents in the infusions of the commercial peppermint tea (Mentha x piperita L.) samples (n = 27) from different countries were studied using HPLC-UV-MS/MS analysis. The most abundant polyphenolics in the peppermint infusion were eriocitrin, 12-hydroxyjasmonate sulfate, luteolin-O-rutinoside and rosmarinic acid. In order to evaluate the content of samples by finding chemosystematic markers, the essential oil composition was studied by GC. The analyses showed that the 24 (89%) peppermint tea samples contained peppermint, whereas three samples may contain Mentha spicata, different from that claimed on the package. The effects of seven peppermint tea extracts against respiratory tract pathogen Chlamydia pneumoniae were investigated in vitro. All seven selected tea extracts were active against C pneumoniae, the growth inhibition ranging from 20.7% to 69.5% at extract concentration of 250 mu g/ml. In most cases, the antichlamydial activity was related to the peppermint teas having also high content of luteolin and apigenin glycosides. This study supports the consumption of peppermint tea to potentially elicit beneficial health effects on acute respiratory tract infections. (C) 2013 Elsevier Ltd. All rights reserved.