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Extraction and HPLC of Hypericin. Courtney Arnott Intermediate Lab Fall 2001. Hypericin – Background and Uses. C 30 H 16 O 8 Marker for active compounds in St. Johns Wort Uses: AIDS, cancer, afterbirth pains, cramps, depression, bacterial and viral infections. Purpose.
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Extraction and HPLC of Hypericin Courtney Arnott Intermediate Lab Fall 2001
Hypericin – Background and Uses • C30H16O8 • Marker for active compounds in St. Johns Wort • Uses: AIDS, cancer, afterbirth pains, cramps, depression, bacterial and viral infections
Purpose To determine the amount of hypericin in different lot numbers of brands of St. Johns Wort to see if there is a significant variation from dose to dose.
Extraction of Hypericin • Three lot numbers of three different brands of St. Johns Wort • 750 mg tablet powder in 40 mL methanol • Sonicate for 15 minutes, dilute to volume (50 mL) • Remove 10 mL, centrifuge for 15 minutes • Expose to fluorescent light for 30 minutes
HPLC • High Pressure Liquid Chromatography • Stationary phase and mobile phase • Diodes measure absorbance across broad band of spectra • Can look at complete UV-vis spectra or chromatograph at particular wavelength
HPLC Theory • Molecules move through column, “stick” to chains of carbon (system is under extreme pressure – 2000+ psi) • Retention time based on size of molecule • Column separates molecules by size, reach detector at different times for absorbance readings
HPLC Column C18 column – 18-carbon chains (stationary phase) attached to silica beads on inside of column
Mobile Phase Solution • 66.6% methanol, 17.2% phosphate buffer (pH 2.1), 16.2% ethyl acetate • pH of buffer keeps OH groups from protonating • Can adjust concentration to change retention times of peaks
HPLC Method • Run solvent blank of methanol • Inject samples • 10 minute method • Observe chromatography at 590nm (visible light range)
Problems and Solutions • Pressure problems with Pump C • Small particles in solvents – changed filters • Sonicated frits to remove debris • Changed pre-column
Data Analysis • All sample graphs showed two peaks – one at 2-3 minutes and one at 6 minutes • First peak suspected to be methanol, second peak hypericin (based on standard data) • Confirmed second peak as hypericin by extracting UV-vis spectra on standard and sample at 6 minutes – spectra matched
Further Data Analysis • Millennium Software integrates peak area • More absorbance = larger peak area = more concentrated sample • Unknown area of sample is put into y=mx+b equation from standard curve • Solve equation to find concentration of sample in ppm
Discussion • Generic brands showed less hypericin than stated, name brand showed more • Generic brand (Food Lion) had most consistent dosage • All samples showed some significant variation between dosages • Most were still within recommended daily dosage amounts
Conclusion • Recommended safe daily dosage for humans is 90 ppm – anywhere from 2.34 to 3.92 300 mg tablets • Data on lethal human dosage unavailable • FDA regulations necessary to ensure safe and consistent dosages
Further Research • Compare results with an FDA regulated medication to further quantify data • Research into properties/uses of hypericin
References • DialogueWeb – Hypericin www.dialogueweb.com • Dictionary of Organic Compounds – Hypericin (p. 3270) • Featured Herb Review – St. John’s Wort www.viable-herbal.com • Institute for Nutraceutical Advancement – Methods “Hypericin and Pseudohypericin by HPLC” www.nutraceuticalinstitute.com • Planta Natural Products – Hypericin (structure and HPLC graph) http://www.planta.at/hyper/hyper.htm