Rapid Quantitation of Furanocoumarins and Flavonoids in Grapefruit Juice using Ultra‐Performance Liquid Chromatography

Abstract

Introduction Grapefruit juice can increase or decrease the systemic exposure of myriad oral medications, leading to untoward effects or reduced efficacy. Furanocoumarins in grapefruit juice have been established as inhibitors of cytochrome P450 3A (CYP3A)-mediated metabolism and P-glycoprotein (P-gp)-mediated efflux, while flavonoids have been implicated as inhibitors of organic anion transporting polypeptide (OATP)-mediated absorptive uptake in the intestine. The potential for drug interactions with a food product necessitates an understanding of the expected concentrations of a suite of structurally diverse and potentially bioactive compounds. Objective Develop methods for the rapid quantitation of two furanocoumarins (bergamottin and 6′,7′-dihydroxybergamottin) and four flavonoids (naringin, naringenin, narirutin, and hesperidin) in five grapefruit juice products using ultra performance liquid chromatography (UPLC). Methodology Grapefruit juice products were extracted with ethyl acetate; the concentrated extract was analyzed by UPLC using acetonitrile:water gradients and a C18 column. Analytes were detected using a photodiode array detector, set at 250 nm (furanocoumarins) and 310 nm (flavonoids). Intraday and interday precision and accuracy and limits of detection and quantitation were determined. Results Rapid (<5.0 min) UPLC methods were developed to measure the aforementioned furanocoumarins and flavonoids. R2 values for the calibration curves of all analytes were >0.999. Considerable between-juice variation in the concentrations of these compounds was observed, and the quantities measured were in agreement with the concentrations published in HPLC studies. Conclusion These analytical methods provide an expedient means to quantitate key furanocoumarins and flavonoids in grapefruit juice and other foods used in dietary substance-drug interaction studies.

Identification of Diet-Derived Constituents as Potent Inhibitors of Intestinal Glucuronidation

“…For example, the IC 50 values of silibinin and isolated constituents silybin A and silybin B (,10 mM) were more than 10 times lower than mean colorectal tissue concentrations following oral administration of 1400 mg silibinin to cancer patients (;140 mM) (Hoh et al, 2006). Likewise, the IC 50 values of naringin and naringenin (,10 mM) were at least 30 times lower than concentrations in citrus juices (.300 mM) (Erlund et al, 2001;Vandermolen et al, 2013). Finally, the IC 50 values of kaempferol and quercetin, which are present Fig.…”

Labeled content of two furanocoumarins in dietary supplements correlates with neither actual content nor CYP3A inhibitory activity

“…This method was modified from a study measuring furanocoumarins in teas, fruits and vegetables that reported MeOH to be the most efficient solvent [25]. Grapefruit juice was extracted as described previously [13] by shaking 240-mL aliquots of juice with three consecutive washes of ethyl acetate (EtOAc).…”

“…At least one supplement, SciFit DHB 300, was labeled to contain 300 mg of pure DHB in each capsule and was presumably intended to be taken concomitantly with other products of the consumer's choice. Grapefruit juice contains between 2.5 and 36.3 μM bergamottin and 0.2 and 89.0 μM DHB [11-13], equating to between 0.2 to 2.9 mg bergamottin and 0.02 to 7.4 mg DHB per 8-oz (240-mL) serving. Grapefruit juice containing 2.2 mg bergamottin and 2.7 mg DHB per 240-mL serving doubled median area under the curve of felodipine relative to control [6].…”

“…The quantification method utilized ultra-performance liquid chromatography (UPLC) for rapid (3.0 min) separation of the supplement extracts, coupled to both a photodiode array (PDA) detector and a triple quadrupole mass spectrometer (MS) for quantification. Based on a previously published study [13], this method was refined for rapid analysis and made use of the MS to identify more easily the analyte peaks in the complex extracts. The quantification method was used to evaluate the labeled vs. actual content of bergamottin and DHB in selected supplements.…”

Stability-indicating densitometric high-performance thin-layer chromatographic method for the quantitative analysis of biomarker naringin in the leaves and stems ofRumex vesicariusL.

“…It is reported to be an effective agent to treat breast cancer [8], progression of hyperglycemia [7], and cardiac diseases [9]. Naringin was determined in human plasma, rat plasma, food products, and different herbal formulations by liquid chromatography-mass spectrometry (LC-MS) [10], ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS) [11], LC-MS/MS [12], and ultra high-performance liquid chromatography (UHPLC) [13]. The HPTLC fingerprint profile was reported on R. vesicarius [14], but a complete validated stability-indicating analytical method has not been reported yet for the quantification of naringin in the stems and leaves of R. vesicarius.…”