Phenolic Composition of the Leaves of Pyrola rotundifolia L. and Their Antioxidant and Cytotoxic Activity
In our study, we found that the leaves of Pyrola rotundifolia contain large amounts of biologically active compounds. Twenty-three compounds were detected in the UHPLC–DAD–MS analysis. Among them, isoquercitrin, guajaverin, monotropein, galloylglucose isomers, quercetin 2′′-Ogalloylgalactoside and epicatechin gallate were described for the first time in the examined species. From the obtained cytotoxic effect values of the ethanolic extract of P. rotundifolia against five leukemic cell lines, it can be concluded that the viability of cells considerably decreased with increasing doses of the examined extract. Many authors found that aqueous and ethanolic extracts have a major destructive effect on tumor cells as compared with nonpolar extracts [60]. It is known that phenolic compounds such as tannins and flavonoids are soluble in ethanol; therefore, they can be the major group of active components for the destruction of leukemic cells. Moreover, the examined extract had good antioxidant activity and can be considered as a radical inhibitor or scavenger. Although further details regarding the effect of P. rotundifolia leaves and their individual compounds against the leukemic cells examined in our study remain to be investigated, the present results suggest that the ethanolic extract would be beneficial in the chemoprevention of leukemia. Furthermore, as a rich source of phenolic compounds with good antioxidant properties, it can be used as a reliable source of natural antioxidants and may be used for food supplement production and in the pharmaceutical and cosmetic industry.
Pyrola rotundifolia L., which is the subject of our research, is a perennial herbaceous plant commonly known as round-leaved wintergreen [15]. Although the whole dried plant has been used for years in traditional medicine for the treatment of hypertension, rheumatic pain, tuberculosis, cancer and various inflammatory diseases [35], and is listed in Chinese Pharmacopoeia [36], the reports regarding the pharmacological activities of P. rotundifolia are limited