Quantitative analysis of isoorientin in several Turkish Gentiana species by High Performance Liquid Chromatography
 Gülnur TOKER*^,°, Mustafa EDİS**, Erdem YEŞİLADA***
 * Gazi University, Faculty of Pharmacy, Department of Pharmacognosy, Etiler, 06330 Ankara, TURKEY
 ** Edis Eczanesi, 13 Şubat Cad. 2/C 24040 Erzincan, TURKEY
 *** Yeditepe University, Faculty of Pharmacy, Department of Pharmacognosy, Ataşehir, 34755, İstanbul, TURKEY
 ° Corresponding Author E-mail: gulnur@gazi.edu.tr

Summary

Gentiana olivieri Griseb. (Afat, Gentianaceae) is used in Turkish folk medicine to reduce high blood glucose level in Southeastern Turkey. Through in vivo bioassay-guided fractionation procedures, the methanolic extract of G. olivieri yielded isoorientin as the active antidiabetic component. Same molecule has also exerted potent anti-inflammatory, antinociceptive, antioxidant and antihepatotoxic activities in rats and mice. Due to the wide range bioactivity profile of isoorientin, it has become important to find alternative herbal sources for this compound to analyze several Gentiana species (G. olivieri Griseb., G. asclepiadea L., G. cruciata L., G. gelida Bieb. and G. septemfida Pallas) for their isoorientin contents. In this study, an HPLC-UV method was used for determination of isoorientin contents in five Gentiana species. The precision of the analytical method was determined by applying the standard and test samples for five times. Standard deviation and relative standard deviation were determined for each sample by using “Instat” as the statistical program. The leaves of all Gentiana species, except G. gelida, were found to have isoorientin at higher concentration levels compared to their flowers and stems, whereas the isoorientin content of G. gelida flowers was higher than the other parts of this species. According to the results of current HPLC analysis, the highest isoorientin content was found in the leaves (3.70%) and flowers of G. olivieri (3.28%), the flowers of G. gelida (3.52%), and the leaves of G. asclepiadea (3.07%), while in lesser amounts in the flowers of G. asclepiadea (1.84%) and the leaves of G. cruciata (2.27%).

Key Words :
Gentiana, G. asclepiadea, G. cruciata, G. gelida, G. olivieri, G. septemfida, HPLC, isoorientin.