Biological effects of gentian root extracts (gentiana lutea)- enzyme inhibition, antioxidative and antimicrobial activity.

Predmet istraživanja doktorske disertacije je bio usmeren na ispitivanjebioloških efekata ekstrakata korena lincure i određivanje njihovog kvalitativnog ikvantitativnog sastava. Ispitivan je uticaj ekstrakata i konstituenata lincure (G. lutea) naaktivnost enzima mijeloperoksidaze (MPO), acetilholinesteraze (AChE) i ekto-ATPaze(E-NTPDaze) sa membrane sinaptozoma. Takođe, određivana je antioksidativna,antimikrobna, radioprotektivna i antiproliferativna aktivnost ekstrakata lincure i njenihkonstituenata. Najzad, ispitan je i uticaj pojedinih konstituenata lincure na procesapoptoze humanih leukocita.Za proučavanje navedenih bioloških efekata pripremljeni su vodeni, kiseli (4%sirćetna kiselina, v/v) i etanolno vodeni (25, 50, 75 i 96% etanola u vodi, v/v) ekstrakti.Genciopikrozid, loganska kiselina, sverozid, svertiamarin, izoviteksin, amarogentin iizogentizin su izabrani kao konstituenti lincure čija je biološka aktivnost ispitivana.Kvalitativni sastav ekstrakata određivan je primenom tečno-masene hromatografije:HPLC-MS/ESI-TOF, MALDI-TOF i UPLC-PDA. Kvantitativna analiza ekstrakatakojom su određivane koncentracije navedenih konstituenata izvšena je pomoću UPLCTQD-MS/MS. Kvantitativnom analizom je utvrđeno da su genciopikrozid i loganskakiselina najzastupljenija jedinjenja u svim ekstraktima (0,9 do 2,5% genciopikrozid i 0,3do 0,9% loganska kiselina), izogentizin je prisutan samo u etanolno vodenimekstraktima (50- 96% EtOH, v/v) a amarogentin i izoviteksin su prisutni u tragovima.Kao najpotentniji inhibitori enzima MPO, AChE i E-NTPDaze su se pokazali etanolnovodeni ekstrakti. Pri koncentraciji od 100 g/mL, 50% i 75% EtOH ekstrakti inhibiraju100% aktivnosti MPO, a u grupi ispitivanih konstituenata najjači inhibitor jegenciopikrozid sa IC50=0,80,1 g/mL (2,25 M). Najviši stepen inhibicije AChE(54%) postignut je sa 75% EtOH ekstraktom, pri koncentraciji od 50 g/mL a odkonstituenata sa loganskom kiselinom (39%) pri C= 6,77 M. Sposobnost inhibicije ENTPDazesu pokazali svi ispitivani ekstrakti u opsegu od 45 do 53% (vodeni i 50%EtOH) pri koncentraciji od 200 g/mL...The objective of the study of this doctoral thesis was focused towardinvestigation of the biological effects of G. lutea extracts and determination of theirqualitative and quantitative composition. The activity of enzymes, myeloperoxidase(MPO), acetylcholinesterase (AChE) and synaptosomal membrane ecto-ATPase (ENTPDase)were investigated. Also, antioxidative, antimicrobial, radioprotective andantiproliferative activity of Gentian extracts and their constituents were determined.Finally, the influence of the individual G. lutea constituents on apoptosis of humanleukocytes was examined.For the study of the mentioned biological effects water, acidic (4 % acetic acid,v/v) and ethanol-water extracts (25, 50, 75 and 96% ethanol in water, v/v) wereprepared. Gentiopicroside, loganic acid, sweroside, swertiamarin, isovitexin,amarogentin and isogentisine were selected as G. lutea constituents whose biologicalactivity was investigated. The qualitative composition of the extracts was determined byliquid chromatography coupled with mass spectrometry: HPLC-MS/ESI-TOF, MALDITOFand UPLC-PDA. Quantitative analysis of the extracts, which was used for thedetermination of the constituent’s concentration, was performed using UPLC-TQDMS/MS. Quantitative analysis showed that the gentiopicroside and loganic acid are themost abundant compounds in all examined extracts (0.9 to 2.5% and 0.3-0.9% ofgentiopicroside and loganic acid, respectively), while isogentisin is only present in theethanol water extracts (50-96%, v/v) and amarogentin and isovitexin are present only intraces. The ethanol water extracts proved to be the most potent inhibitors of MPO,AChE and E-NTPDase enzymes.At a concentration of 100 μg/ml, 50% and 75% EtOH extracts inhibited 100% ofMPO activity, and in the group of examined constituents the strongest inhibition wasachieved with gentiopicroside with an IC50 = 0.80.1 g/mL (2.25 M). The highestdegree of inhibition of AChE (54%) was obtained with 75% EtOH extract at aconcentration of 50 g/mL while in the group of constituents the highest degree of..