Investigation of Ursolic Acid Supplement Purity

Ursolic acid (UA) is a phytochemical found in the waxy coat of a variety of fruits including apples and cherries, and in herbs like rosemary and thyme. A multitude of studies have shown UA administered to rodents provide health benefits in diseases like cancer, cardiovascular disease, diabetes, obesity, liver disease, kidney disease, and neurodegenerative diseases, but the therapeutic effects in humans has yet to be investigated. A high purity UA supplement with a known quantity of UA would be required to conduct valid studies exploring the potential positive health benefits of UA in humans. Therefore, we investigated the dissolution, theoretical weight, and purity of UA supplements available for purchase in this study. METHODS Four oral UA dietary supplements containing UA from rosemary extract and one topical use UA spray were purchased from the internet for analysis. Oral UA dietary supplements were tested for disintegration using 37°C water and agitation for 45 minutes while observations were collected every 30 seconds. Percent of theoretical weight was determined by weighing the dietary supplement capsule and powder independently for comparison to the serving size listed on the Supplement Facts Panel. Purity of UA dietary supplements were tested by high performance liquid chromatography–electrospray ionization mass spectrometry (HPLC‐ESI‐MS). Data‐dependent analyses were conducted using one full MS scan followed by six tandem MS scans with electrospray negative ion detection. UA dietary supplements were dissolved in either methanol or dimethyl sulfoxide (DMSO). Quantitative results were obtained by reference of the experimental peak area ratios to the standard curve. UA from Sigma‐Aldrich was used to create the standard curve. RESULTS/FINDINGS Based on capsule weight, all UA dietary supplement capsules disintegrated within 6 to 7 minutes, meeting the dietary supplement disintegration requirements for rupture in less than 30 minutes. All capsulated supplements averaged 100% of the theoretical weight. When quantifying the amount of UA in the supplements by mass spectrometry, the supplements ranged from 14–49% UA and the topical spray contained 0.4% UA. CONCLUSIONS/IMPLICATIONS All tested UA dietary supplements passed the disintegration test, and thus are likely accessible for absorption when ingested orally, and provide the serving amount stated on the Supplement Facts Panel. The bioavailability of UA from these supplements needs further investigation. The highest dietary supplement UA content was 49%, but to study the effect of UA in humans, a more pure UA extract needs to be utilized in human studies to determine the therapeutic effects and mechanism of action of UA. Support or Funding Information Funding provided by UTSA College of Education and Human Development Faculty Research Award 2014–2015