INHIBITION OF AMYLIN FIBRIL FORMATION AND PROTECTION OF ISLET β-CELLS BY MEDICINAL PLANTSAbstract
Misfolding of some proteins, their self-assembly into insoluble amyloid structures underlies many diseases, constituting a group of amyloid-related pathology. Fibrillation of peptide hormone of the pancreas, amylin, is considered as one of the causes of death of β-cells in type 2 diabetes. In this work we studied in-vitro protection of islet β-cells from death in the presence of aggregated amylin by ethanol extracts of rose petals (Rosa damascena), melilot (Melilotus officinalis), leaves of grape (Vitis vinifera), sorrel (Rumex confertus) and blackberry (Rubus caesius), and by eleven fractions, isolated from these plants (Coumarin, phenol glycoside, flavonoid and anthracene derivative). A rather low IC50 values in protection of β-cells were estimated for the extracts (0.03-1.5 µg/ml) and their fractions (0.04-3.9 µg/ml). The inhibition of amylin aggregation by several plant extracts and fractions in-vitro was studied using ThT fluorescence method. The IC50 values in deceleration of the peptide aggregation were between 1.76-7.24 µg/ml. A strong correlation (r = 0.99, p=0.0005) was observed between IC50 values in the protection of β-cells and amylin aggregation. Probably, both of these processes are conditioned by prevention of amylin aggregation and decomposition of its preformed aggregates by plant preparations. These results allow recommending frequent use of effective plants by persons at risk group and considering these plants as sources for anti-diabetic agents.
S. G. Sharoyan*, A. A. Antonyan, H. A. Harutyunyan and S. S. Mardanyan
H. Buniatyan Institute of Biochemistry of Armenian National Academy of Sciences, Republic of Armenia
17 January 2015
19 March 2015
27 April 2015
01 May 2015