Investigations on Tyrosinase and Cholinesterase Enzyme Inhibitory Potentials of Cistus L. Species Naturally Distributed in Turkey
Project no. 21061 · Status: Kapanmış · 2019
Summary
The genus Cistus (Cistaceae) is represented by 21 taxa in the world and by 5 taxa in the flora of Turkey. These species are Cistus creticus L., Cistus laurifolius L., Cistus monspeliensis L., Cistus parviflorus Lam. and Cistus salviifolius L.. In traditional folk medicine, Cistus species are used various medical purposes such as rheumatism, stomach ache, upper respiratory tract infections, skin diseases, burns and wounds, diabetes. Phytochemical investigations on Cistus species are generally contained flavonoids, terpenic compounds (labdane type diterpene) and essential oil. In this study, %80 ethanol extracts prepared from the leaves of the 5 Cistus species distributed in Turkey and tyrosinase, acetylcholinesterase and butyrylcholinesterase enzyme inhibitor activities of these extracts were investigated. Fractionation and isolation studies were carried out from the most active C. creticus extract by various chromatographic methods. Structures of the isolated compounds are established using spectroscopic methods (1D NMR). In ezyme inhibition experiments, all Cistus extracts were found reasonably active on all enzymes. As a result of tyrosinase, asetylcholinesterase and butyrylcholinesterase enzyme inhibition experiments; extract of C. creticus approached the reference compounds respectively; (Kojic acid, IC50=4.62±0.04 µg/mL) 44.6-times (IC50=206 µg/mL); (Galantamine, IC50=0.23±0.01 µg/mL) 713-times (IC50=164 µg/mL); (Galantamine, IC50=2.29±0.07 µg/mL) 8.3-times (IC50=19 µg/mL) and it showed the strongest effect. As a result of the enzyme inhibition experiments; CCE extract obtained by different polarity fractionation studies, approached the reference compounds respectively; 37-times (IC50=171±1.73 µg/mL), 521-times (IC50=120±10.38 µg/mL) and 37-times (IC50=85±1.73 µg/mL) and it showed the strongest effect. The highest enzyme inhibition showed by the fractions; Fr. 12 against tyrosinase, Fr. 11 against acetylcholinesterase, Fr. 1, Fr. 2 and Fr. 11 against butyrlcholinesterase which are obtained from CCE extract. However, isolation from these fractions could not be achieved. In order to determine the molecules in the most effective Cistus VI extract, Tiliroside and İsoquercitrin were isolated from C. creticus. İsoquercitrin approached the reference compound 52.8-times (IC50=120.83±5.37 µg/mL) and it showed enzyme inhibitor effect against the butyrylcholinesterase enzyme. This is the first study where the tyrosinase, asetylcholinesterase and butyrylcholinesterase inhibitor activities were investigated comparatively of the extracts of 5 Cistus species distributed in Turkey.