135 Bulgarian Chemical Communications, Volume 47, Number 1 (pp. 135 – 143) 2015 Simultaneous analysis of glycyrrhizic acid and preservatives in licorice aqueous extract by HPLC/PDA detection K. Abu-Shandi 1 , A. R. Halawah 2 , AlSayed Sallam 3 , Gh. Al-Edwan 4 , A. R. Al-Tawaha 5 , Sh. A. Albajawi 2 , E. S. M. Abu-Nameh 2* 1 Department of Chemistry, Faculty of Science, Tafila Technical University, Tafila, Jordan 2 Department of Chemistry, Faculty of Science, Al-Balqa Applied University, Al-Salt, Jordan. 3 Al-Taqaddom Pharmaceutical Industries, Amman, Jordan. 4 DAD Industries, Amman, Jordan. 5 Department of Biological Sciences, Al Hussein Bin Talal University, Maan, Jordan. Received January 29, 2014; Revised March 13, 2014 A high performance liquid chromatographic (HPLC) analytical method for the assay of glycyrrhizic acid (GLY), sodium benzoate (SB), methyl 4-hydroxybenzoate (MP), and propyl 4-hydroxybenzoate (PP) in licorice aqueous extract was developed. The method employed Lichro CART® Purospher STAR, C18, 5 µm (250 × 4.6 mm) analytical column with a simple mobile phase of potassium acetate buffer: acetonitrile (68.8: 31.2) v:v ratio. The detection was achieved by PDA detector at a wavelength of 254 nm. The developed method was considered linear within the specified range at concentrations of 80%, 90%, 100%, 110% and 120%. The method was found to be accurate, repeatable and precise. Upon storage in 0.1N HCl for 24 h, 0.1N NaOH for 24 h, and 3% H2O2 with exposure to UV for 24 h and heating in water bath at 90 ºC for 24 h, methyl paraben (MP) was stable upon changing conditions. The other tested components exhibited different stability properties upon changing conditions. Keywords: glycyrrhizic acid (GLY), sodium benzoate (SB), methyl 4-hydroxybenzoate (MP), propyl 4- hydroxybenzoate (PP), validation, Arrhenius plots. INTRODUCTION Liquorice or licorice [1, 2] is the root of Glycyrrhiza glabra from which a somewhat sweet flavor can be extracted. Licorice extract is produced by boiling licorice root and subsequently evaporating most of the water, and is traded both in solid and syrup forms [3, 4, 5]. Its active component is glycyrrhizin known as glycyrrhizic acid (GLY) (Figure 1), a sweetener from 30 to 50 times sweeter than sucrose, which also has pharmaceutical effects [6]. Fig. 1. The chemical structure of glycyrrhizic acid (GLY), the major active component in licorice. Several studies have investigated the main components in licorice root extract for anti- inflammatory activity [7-10]. The effects of the aqueous extract of Glycyrrhiza glabra on the depression in mice using forced swim test (FST) and tail suspension test (TST) have been investigated [11]. Ethanolic extracts of the dried roots of Glycyrrhiza glabra were analyzed for their phytochemical constituents. The analysis showed the presence of various phytochemicals like alkaloids, cardiac glycosides, flavonoids, HCN, indoles, juglones, phenols, saponins, steroids, tannins and terpenoids [12]. An ionic liquid based single-drop microextraction procedure followed by HPLC has been developed and validated for the determination of the components of licorice tablets [13]. Several research studies have been conducted and reported in the literature on the analysis of licorice and its extract. For example, Qiao Xue and coworkers investigated the regulatory effects of licorice on bile acid metabonome in rats using liquid chromatography coupled with tandem mass spectrometry [14]. Also, Farag and coworkers utilized multi-targeted metabolic profiling and fingerprinting techniques to study the Glycyrrhiza species components [15]. Moreover, licorice and its extract were quantitatively determined by two- dimensional liquid chromatography [16], inductively coupled plasma atomic emission spectrometry [17], HPLC-ESI-MS/MS [18], high- performance thin-layer chromatography (HPTLC) [19,20], HPLC-UV detector with external standard * To whom all correspondence should be sent: E-mail: eyadchem@yahoo.com © 2015 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria