Anticholinesterase and antityrosinase activities of endemic <i>Prangos heyniae</i> H. Duman & M. F. Watson and its metabolites

Background and Aims: Prangos Lindl. ( Apiaceae) are abundant in coumarins. Previously, along with n-hexane(HEX), chloroform(CHCl3), and methanol(MeOH) extracts, 8 molecules named osthol(1), isoimperatorin(2), oxypeucedanin(3), 7-methoxy-isoarnottinin-4'-O-beta-D-glucopyranoside(4), 7-methoxy-isoarnottinin-4'-O-rutinoside(5), oxypeucedanin hydrate-3'-O-beta-D-glucopyranoside(6), 1-methylethyl-6-O-D-apio-beta-D-furanosyl-beta-D-glucopyranoside(7), and cnidioside A(8) were obtained from the roots of endemic Prangos heyniae H. Duman & M. F. Watson. 4 and 5 were reported as novel compounds. Coumarins are known for their neuroprotective properties. Tyrosinase and cholinesterase enzymes play a key role in the course of neurodegenerative diseases such as Parkinson's and Alzheimer's disease(AD), respectively. Therefore, we aimed to evaluate the antityrosinase and anticholinesterase effects of the extracts and compounds 1-8 from Prangos heyniae roots.

Methods: Tyrosinase and acetylcholinesterase-butyrylcholinesterase(AChE-BChE) inhibitory activities of the samples were evaluated spectrophotometrically. The screening of the samples was carried on at 1000 mu g/mL.

Results of triplicate analyses of the samples were given as IC50 values obtained through linear regression analysis. Kojic acid and galantamine were used as positive controls for antityrosinase and anticholinesterase experiments, respectively. Results: Only MeOH extract showed antityrosinase activity with an IC50 value of 543.37 +/- 7.45 mu g/mL. CHCl3 extract exhibited both AChE and BChE inhibitory activities with IC50 values of 273.92 +/- 32.07 and 38.68 +/- 2.56 mu g/mL, respectively. Among tested compounds, 6 showed a weak BChE-specific inhibitory activity (IC50= 91.93 +/- 3.86 mu g/mL) and managed to possess 40 times inferior activity than galantamine(IC50= 2.25 +/- 0.05 mu g/mL).

Conclusion: The CHCl3 extract displayed a good BChE inhibitory activity. These findings suggested that Prangos heyniae could be a valuable natural source to develop novel BChE inhibitors with further studies against AD.