The Commiphora mukul plant grows in the arid areas of

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1 24 NAGARAJAN ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 84, NO. 1, 2001 DRUGS, COSMETICS, FORENSIC SCIENCES Simultaneous Determination of E- and Z-Guggulsterones in Dietary Supplements Containing Commiphora mukul Extract (Guggulipid) by Liquid Chromatography MYTHILI NAGARAJAN, TED W. WASZKUC, and JIDONG SUN Enzymatic Therapy, 825 Challenger Dr, Green Bay, WI Guggulipid, the standardized product from the extraction of the ole-gum-resin from the Commiphora mukul plant, has been marketed as a hypolipidemic agent. The ketosteroids, cis- and trans-4,17(20)-pregnadiene-3,16-dione, known as E- and Z-guggulsterones, respectively, are the main ingredients in guggulipid. A liquid chromatographic method was developed for simultaneous determination of E- and Z-guggulsterones in guggulipid preparations using synthetic E- and Z-guggulsterone standards. Realtively low amounts of guggulsterones (E and Z) were found in commercial guggulipid preparations in comparison with the manufacturer s claim of 2.5%. The mixture of E- and Z-guggulsterones was extracted and separated on a Symmetry C 18 reversed-phase column, with a mobile phase of acetonitrile water ( , v/v) and detected at 242 nm. The retention times of E- and Z-guggulsterones are approximately 8 and 11 min, respectively. Assay quantitation was based on the calibration curve obtained from a mixture of synthetic standard E- and Z-guggulsterones. Experimental data on selectivity, linearity, accuracy, and recoveries are presented. The Commiphora mukul plant grows in the arid areas of the Rajasthan and Gujarat states of India (1). Guggulipid, an extract from Commiphora mukul, Burseraceae, has been marketed as a hypolipidemic drug in India (2). The gum resin of C. mukul, called guggulipid, has been widely used in Ayurvedic medicine for the treatment of epilepsy, ulcers, obesity, rheumatoid arthritis, and hyperlipemia in Indian medicine; it also exhibits cytotoxic activity against a human lung cancer cell line (3). Various fractions have been investigated experimentally and clinically (4, 5). A standardized fraction containing the guggulsterone with some other steroids, esters, and higher alcohols has been extensively investigated at the Central Drug Research Institute of India, and termed guggulipid. Received October 4, Accepted by JM May 30, The compounds of greatest pharmacological interest are the 2 ketosteroids, E- and Z-guggulsterones, which are the geometrical isomers (cis and trans) of pregna-4,17(20) diene-3,16-dione (6, 7). Administration of a mixture of 2 guggulsterones has led to increasing low density lipoprotein (LDL) receptor sites, enhancing catabolism of LDL through the receptor, and, hence, decreasing cholesterol, phospholipid, and triglyceride levels (8 15). Other components appear to exert synergistic effects with regard to lipid lowering action. The beneficial cardiovascular effects of guggulsterone may also be related to its antioxidant activity and possible role as a scavenger of hydroxyl free radicals (OH-) to protect low density lipoprotein (16 18). The Z-guggulsterone also displays a thyroid stimulating action (19). Both E- and Z-guggulsterones induce an increase in the activity of catecholamines and dopamine-β-hydroxylase enzyme (20). The purified product seems to be neither a mutagen nor a teratogen, and several double blind clinical trials in humans have demonstrated the efficacy of prolonged administration of guggulipid in the treatment of certain types of hyperlipidemia, hypercholesterolemia, and hypertriglyceridemia (21, 22). Because the amount of E- and Z-guggulsterones varies largely in C. mukul, they must be quantitated. Liquid chromatographic (LC) methods for the determination of Z-guggulsterone in plasma and marketed pharmaceutical formulations and serum have been reported (23, 24). Simultaneous quanititation of both E- and Z-guggulsterones necessitated the development of a simple and sensitive assay. This study describes the development and validation of an LC method for simultaneous determination of Z- and E-guggulsterones in guggulipid preparations. The quantitation was based on the calibration curve obtained from synthetic standards of E- and Z-guggulsterones, synthesized by Steraloids, Inc., Wilton, NH (25). Experimental Reagents and Standards Analytical standards of E- and Z-guggulsterones were synthesized by Steraloids, Inc., and the structure was established by Proton nuclear magnetic resonance, ultraviolet, infrared analysis, melting point, and thin-layer chromatography. LC grade acetonitrile was obtained from Fisher Scientific (Chicago, IL). Water was purified by a D4700 Nanopure ana-

2 NAGARAJAN ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 84, NO. 1, Figure 1. Chromatogram of E- and Z-guggulsterones in the standard mixture. lytical deionization system (Barnstead Thermodyne Co., Dubuque, IA) capable of delivering 18 MΩ water. Apparatus and Chromatographic Conditions The LC system was equipped with Waters 600S controller, 616 pump, 717 autoinjector, and 996 photodiode array detector. Separation was accomplished on a Symmetry C 18 steel column, mm id, 4 µm particle size, with a Sentry C 18 guard column, mm id, 4 µm (Waters Associates, Milford, MA). Chromatographic data were processed with Waters Millenium software version The mobile phase was acetonitrile water ( , v/v), degassed under vaccum using an in-line degasser. The system was operated at ambient temperature (ca 25 C) and a flow rate of 1.0 ml/min with UV detection at 242 nm. Preparation of Standard and Sample Solutions (a) Stock standard solution, 1 mg/ml. Prepared by dissolving each 10 mg E- and Z-guggulsterone in 10.0 ml acetonitrile separately. (b) Working standard solution for calibration. Calibration standard solutions were prepared by dilution of stock standard solution of ca 0.01, 0.02, 0.05, 0.1, 0.15, and 0.2 mg/ml Figure 2. Chromatogram of E- and Z-guggulsterones in the commercial formulation sample.

3 26 NAGARAJAN ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 84, NO. 1, 2001 Figure 3. Contour plot of E- and Z-guggulsterones. with acetonitrile. All standard solutions were filtered through 0.45 µm disposable nylon filters before injection. (c) Working sample solution. Prepared by transferring sample, equivalent to 3.0 mg E- and Z-guggulsterones, into 50 ml volumetric flask, sonicating with acetonitrile for 30 min, and diluting to 50.0 ml with acetonitrile. A portion of it was filtered through a 0.45 µm nylon filter before injection into the LC system. (d) LC injection volume. 20 µl. Method Validation (a) Linearity and range. Linearity is the measure of a test method s ability to obtain test results directly proportional to the concentration of analyte in the sample. To examine the linearity of the absorbance as a function of the concentration, 6 standard solutions of ca 0.01, 0.02, 0.05, 0.1, 0.15, and 0.2 mg/ml of total E- and Z-guggulsterones were prepared and injected. Linearity was established by plotting the peak areas vs concentration. The slope, intercept, and correlation coeffecient were calculated by linear regression analysis. (b) Limit of detection (LOD) and limit of quantitation (LOQ). LOD is the lowest concentration of the analyte in a sample that can be detected, but not necessarily quantitated. It is measured by determining the concentration of the standard solution of the analyte that can give a signal-to-noise ratio of 3:1. LOQ is the injected amount which results in a reproducible measurement of peak areas. It is measured by determining the concentration of the standard solution of the analyte that can give a signal-to-noise ratio of 10:1. The average base line noise (BLN) was measured on 6 chromatograms of sample solutions. From the average noise signal, LOD and LOQ were extrapolated from the linearity plot. (c) System precision. Precision is defined as the agreement of 2 or more measurements that are obtained under identical conditions using the same test method. System precision should be routinely assessed on a daily basis as part of the system suitability studies (tailing factor, reproducibility of the re- Table 1. Concn expected, mg System precision for E- and Z-guggulsterones E - and Z-guggulsterones Concn found, mg (mean ± SD) CV, % Recovery, % ± ± ± ±

4 NAGARAJAN ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 84, NO. 1, Table 2. Method precision and accuracy for E- and Z-guggulsterones E- and Z-guggulsterones Spiking level, % Sample concn, Spike amount added, Nominated concn, Actual concn, CV, % Error, % Recovery, % ± ± ± sponse, etc.). System precision was determined by analyzing 3 concentrations of standard mixtures of E- and Z-guggulsterones ranging from 0.08 to 0.2 mg/ml in 5 replicates on the same day. Mean, standard deviation, and percent coefficient of variation were calculated. (d) Method precision and accuracy. Accuracy is defined as the agreement between a measured value and true value. Accuracy can be examined by comparison with another method or by the standard addition method when dealing with plant preparations. We preferred to determine the accuracy by the standard addition method. Both precision and accuracy were determined by spiking a product (tablet) containing E- and Z-guggulsterones and a matrix of vitamins, minerals, and other herbal extracts with the standard mixture of E- and Z-guggulsterones at 50, 100, and 150% levels (0.025, 0.52, and mg; n = 4 for each level). The following equations (26) were used to calculate precision and accuracy: Precision is expressed as the coefficient of variation (CV): CV,%= Standard deviation Mean 100 Accuracy was determined by the percent difference of the mean concentration from the known concentration: Error, % = Mean concentration nominal concentration 100 Nominal concentration (e) Robustness. Robustness of a method is a measure of its capacity to remain unaffected by small but deliberate variations in method parameters. It was determined through 2 experimental procedures: several times extraction vs single extraction; continuous extraction with acetonitrile in a Soxhlet apparatus for several hours. One of the formulations in tablet form was used for this and the final results of both experiments were compared with the repeatability data. (f) Selectivity. An analytical determination of a compound is defined as selective, when, with a certain probability and accuracy, the determined compound can be distinguished from related substances, impurities, etc. An important tool in the evaluation of the selectivity is contour plot by photodiode array detector. In a contour plot, the data are presented as concentric isoabsorptive lines in the (absorption, time) plane, so that all the data can be observed simultaneously. Major coeluting peaks with different UV spectrum will disturb the normally symmetrical concentric lines of a peak. Application Nine different commercial formulations were purchased in the United States and analyzed by this method. Among the 9 formulations, the first 6 contained only guggulipid extract and the remaining 3 were 2 capsules (Nutrition Warehouse, Mineola, NY and Nature s Plus, Melville, NY; both capsules were purchased from local health food stores) and one tablet. The capsules and the tablet contained complex matrixes consisting of vitamins, minerals, and other herbal extracts in addition to guggulipid extract. Results and Discussion The guggulsterone peaks E and and Z were identified at 242 nm by coelution with a spike of standard guggulsterones. E- and Z-guggulsterones were eluted at 8 and 11 min, respectively (Figures 1 and 2). The tailing factor for E- and Z-guggulsterone peaks was <1.0. Using the photodiode array detector, a contour plot was developed. In the contour plot, data are presented as concentric isoabsorptive lines in the (absorption, time) plane, so that all the data can be observed simultaneously. Major coeluting peaks with different UV spectrum disturb the normally symmetrical concentric lines of a peak. The contour plot of E- and Z-guggulsterones showed no major impurity (Figure 3). A linear relationship existed between peak areas and guggulsterone concentrations. Linear regression analysis of the standard curve yielded a correlation coefficient of 0.999, which is indicative of proper method performance. The LOD was estimated as mg/ml and the LOQ was mg/ml. System precision study using the mixture of standard E- and Z-guggulsterones on 4 different concentrations yielded a CV <2%, and recovery was >96% (Table 1). Method precision and accuracy study using one of the formulations in tablet form yielded a CV <2% and percent recovery >97. Good recoveries of spiked samples in the range of % demonstrate that the method has no significant matrix interference (Table 2). Robustness of the method was measured by using the formulation in the tablet form, and the percent recovery was cal-

5 28 NAGARAJAN ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 84, NO. 1, 2001 Table 3. E- and Z-guggulsterones in commercial formulations Product Type Total E- and Z-guggulsterones, % (w/w) Label claim, % (w/w) Recovery, % 1 Extract Extract Extract Extract Extract Extract Capsule Tablet Capsule culated and compared with the percent recovery of the single extraction procedure. Both Soxhlet extraction and multiple extraction procedures yielded percent recovery values >97%, very similar to that by single extraction. This finding shows that the effeciency of the sample preparation by single extraction procedure is as good as multiple extractions and continuous extraction in a Soxhlet apparatus for several hours. This method was also used to determine the amount of E- and Z-guggulsterones in 9 commercial formulations. The total amount of E- and Z-guggulsterones claimed for each formulation was 2.5%; however, the amount detected varied from 0.33 to 2.23% (Table 3). Conclusion The proposed LC method for determining the sum of E- and Z-guggulsterones is simple, accurate, and selective. The assay quantitation is based on the calibration curve obtained with pure standards of E- and Z-guggulsterones, which are now readily available and inexpensive. Acknowledgments The project was supported by Enzymatic Therapy, Inc., Green Bay, WI. We thank Terry Lemerond and Matt Schueller for their encouragement and continuous support. References (1) Chopra, R.N., Chopra, I.C., Handa, K.L., & Kapur, L.D. (1958) Indigenous Drugs of India, U.N. Dhur & Sons, Pvt. Ltd., Calcutta, India (2) Singh, V., Kaul, R., Chandar, R., & Kapoor, N.K. (1990) Pharmacol. Res. 22, (3) Perspectives in Natural Product Chemistry (1989) A.U. Rehaman (Ed.), Elsevier Science Publishers, Amsterdam, The Netherlands, Vol. 5, p. 715 (4) Malhotra, C.L., Agarwal, Y.K., Mehta, V.L., & Prasad, S. (1977) Indian J. Med. Res. 65, 390 (5) Ahuja, M.M.S., Malhotra, S.C., & Tandon, H.D. (1977) Indian J. Exp. Biol. 15, 143 (6) Bajaj, A., & Dev, S. (1982) Tetrahedron 38, (7) Nityanand, S., & Kapoor, N.K. (1975) Indian J. Pharmacol. 7, 160 (8) Satyavati, G.V. (1988) Indian J. Med. Res. 87, (9) Dey, A.C. (1980) Indian Medicinal Plants Used in Ayurvedic Preparations,54 (10) Patil, V.D., Nayak, R.U., & Dev, S. (1992) Tetrahedron. 28, (11) Duwiejua, M., Zeitlin, J.I., Wateramn, P.G., Chapman, J., Mhango, J.G., & Provan, J.G. (1993) Plant. Med. 59, (12) Arya, P.V. (1988) Drugs of the Future 13, 618 (13) Kotial, J.P., Bisht, D.B., & Singh, D.S. (1979) J. Res. Indian Med. Yoga. Homeo. 14,11 (14) Nityanand, S., & Kapoor, N.K. (1973) Indian J. Exp. Biol. 11, 395 (15) Satyavati, G.V., Dwarakanath, C., & Tripathi, S.N. (1950) Indian. J. Med. Res. 51, 800 (16) Singh, K., Chander, R., & Kapoor, N.K. (1997) Phytother. Res. 11, (17) Mester, L., & Nityanand, S. (1979) Plant. Med. 37, 367 (18) Bordia, A., & Chuttani, S.K. (1979) Indian J. Med. Res. 70, 992 (19) Tripathi, Y.B., Tripathi, P., Malhotra, O.P., & Tripathi, N. (1984) Plant. Med. 50,78 (20) Srivastava, S., & Kapoor, N.K. (1984) Curr. Sci. 53, 1131 (21) Nityanand, S., & Kapoor, N.K. (1975) Indian. J. Pharmacol. 7, 106 (22) Nityanand, S., Asthana, O.P., Gupta, P.P., & Kapoor, N.K. (1981) Indian. J. Pharmacol. 13, 59 (23) Sane, T.R., Bhate, R.V., Malkar, B.V., Nayak, G.V., & Kothurkar, M.R. (1990) Indian Drugs 28, (24) Singh, K.S., Verma, N., & Gupta, C.R. (1995) J. Chromatogr. B. 670, (25) Benn, R.W., & Dodson, M.R. (1963) J. Org. Chem. 29, (26) Gordon, B.H., Bakes, D.M., Bennett, P., LeBras, B., Walther, B., Lucas, C., Marc, S., & Gouyette, A. (1994) J. Chromatogr. B. 657,

Application Note. Commiphora mukul; Balsamodendron mukul; Commiphora wightii. Treatment of hyperlipidemia, reduction of lipid and cholesterol levels

Application Note. Commiphora mukul; Balsamodendron mukul; Commiphora wightii. Treatment of hyperlipidemia, reduction of lipid and cholesterol levels Application Note 0053 - Guggul for Guggulsterones by HPLC As published in The Handbook of Analytical Methods for Dietary Supplements Botanical Name: Common Names: Commiphora mukul; Balsamodendron mukul;