Extraction and identification of major polyphenol constituents of Northern Hungarian horsemint (Mentha longifolia L. (L.))

(Mentha longifolia (L.) L.) is a less studied species from the viewpoint of its nonvolatile constituents and this work is the first phytochemical screening of it in Hungary. The aim of the experiments is to elaborate an efficient extraction method of its polyphenolic antioxidants. Thirty-six accessions were sampled. Soxhlet and an ultrasonic extraction were applied, both with methanol (MeOH) and ethanol:water 7:3 (WA). The analysis of the extracts was carried out by HPLCDAD method. Rosmarinic acid, hesperidin, diosmin and cynaroside were observed to be common constituents of all samples. Other major constituents were observed in all of the chromatograms at ca. tR=13.5 min. and tR=19.7 min (unknown A and B). Their identification needs further examination. Regarding antioxidant activity, WA extraction was more efficient than MeOH Soxhlet extraction.