The goal of this research was to determine the concentration of hyperforin in St. John’s wort capsules. St. John’s wort is an herbal supplement commonly used as an over-the-counter antidepressant. The active ingredients in the herb include hypericins and hyperforin. While hypericins are frequently quantified by supplement manufacturers and the value listed on the product label, hyperforin is not quantified. Because herbal supplements are not regulated by the Food and Drug Administration (FDA) it is expected that the concentration of hyperforin will vary widely in different St. John’s wort supplements. This research focuses on quantifying the hyperforin concentration in five different herbal supplements. Hyperforin was extracted from the capsule’s herbal contents by sonicating the herb in methanol. The temperature of the bath was kept below 28 °C and the extraction was performed in low light conditions to prevent degradation of the hyperforin. The extract was diluted to 50 mL with methanol and filtered using a 0.45 μm PTFE filter. Ten microliters of the sample was then injected into a High Performance Liquid Chromatograph (HPLC) with UV-VIS absorbance detection (270 nm). The column used was a Phenomenex Luna phenyl-hexyl column (15 cm x 4.6 mm with 3 μm particle size). Isocratic elution was performed with a mobile phase mixture of 90/10 acetonitrile (with 0.3% phosphoric acid)/water at 0.6 mL/min. The hyperforin peak areas were converted into concentrations using a calibration curve constructed from hyperforin standard solutions. Five different St. John’s wort supplements were studied: the organic supplements from Wilde Herb and EarthWise Organics and the conventional supplements from Vitamin Shoppe, Solar Ray, and Solar Ray Guaranteed Potency. Overall, the Vitamin Shoppe brand contained the highest percentage of hyperforin per capsule (0.3694% by mass), while the organic brands Wilde Herb and EarthWise Organics contained the lowest concentrations of hyperforin (0.0215% and 0.0199%, respectively). A price comparison was also made, comparing the cost per gram of herb with the percent by mass content of hyperforin. The two organic supplements studied were the most expensive for the least amount of hyperforin active ingredient while the Vitamin Shoppe brand provided the best overall value for the most hyperforin.

Analysis of hyperforin in St. John's wort capsules

252nd National Meeting (2016)

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