Protection of hippocampal and islet beta cells in vitro by emodin from leaves of Rumex confertus

The natural anthracene derivative emodin (1,3,8-trihydroxy-6-methylanthraquinone) is known as an anticancer agent. In the present work it was isolated for the first time from the ethanol extract of Rumex confertus leaves, widely used in Armenia as a vegetable. It was purified in two-step low pressure liquid chromatography – a significantly easier and inexpensive procedure compared with those used for emodin purification. The purified preparation was characterized by chemical and TLC analyses, NMR, UV-Vis and fluorescence spectra. A rather high cytotoxicity toward cultivated primary cells of mice Ehrlich ascites carcinoma was demonstrated for both the ethanol extract (IC50 = 0.3 ± 0.04 μg/ml) and emodin (IC50 = 40 ± 10 ng/ml) from Rumex confertus leaves. Along with the anticancer activity, these preparations protected a) hippocampal cells against toxic action of aggregated amyloid Aβ (1-40) and Aβ (1-42) peptides, and b) the islet β-cells against death in the presence of aggregated pancreas peptide hormone amylin. The obtained results provide a rationale for developing anticancer, neuroprotective and antidiabetic remedies from the leaves of Rumex confertus