EVALUATION OF ANTIOXIDANT AND ENZYME INHIBITORY ACTIVITY OF FOUR ECHIUM SPECIES.

Herbal medicine has proven to be effective in the treatment of a variety of disorders and has aided in the development of new medications. The genus Echium belongs to Boraginaceae family1, have been used for different purposes in Turkish Folk Medicine2, however some species have not been examined in detail in terms of enzyme inhibition activity. We aimed to evaluate the antioxidant activity, inhibiting effect on digestive enzymes linked to diabetes and Alzheimer disease related acetylcholinesterase and butyrylcholinesterase, skin whitening effect related enzyme tyrosinase of ethanol extracts obtained from four different Echium species namely E. italicum, E. vulgare, E.angustifolium and E. parviflorum. The antioxidant effect of extracts was investigated with DPPH• (1,1-diphenyl-2-picryl-hydrazil), ABTS•+ (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging and iron chelating tests. Total phenol and flavonoid contents were determined with Folin-Ciocalteu and aluminum chloride colorimetric methodrespectively. The anticholinesterse activity related with Alzheimer's disease wastested with Ellman's methods on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). In a result the highest total phenolic (43.58±3.56mgGAE/g extract) was found in E. italicum herba extract and total flavonoid content (105.59±2.93 mgQE/g extract) was found in E. parviflorum aerial part extract. The highest AChE and BChE inhibitory activity were found in aerial part extract of E. italicum (IC50=46.39±0.35 µg/mL and IC50=11.59±0.52 µg/mL). However, the highest tyrosinase inhibitory activity was found in E. parviflorum aerial part extract (IC50=1.83±1.06 mg/mL). This is the first report that these biological activities investigated in four Echium species and theses are thought that these studies could contribute to the advanced pharmacological activity studies and chemotaxonomy of the genus. [ABSTRACT FROM AUTHOR]