88-4 |
Instability of St. John's wort in fruit drink |
C. Y. W. ANG1, L. Hu1, Y. Cui1, W. Luo1, T. Heinze1, A. Mattia2, and M. J. Dinovi2. (1) National Center for Toxicological Research, U.S. Food & Drug Administration, Division of Chemistry, 3900 NCTR Rd., HFT-230, Jefferson, AR 72079-9501, (2) Center for Food Safety & Applied Nutrition, U.S. Food & Drug Administration, Office of Food Additive Safety, 5100 Paint Branch Pkwy., HFS-255, College Park, MD 20740-3835 Botanical dietary supplements have been promoted as natural remedies. Recently, some top-selling bioactive botanicals including St. John's wort (Hypericum perforatum L.) were used in conventional foods and marketed as functional foods. However, no information is available regarding the stability and safety of these ingredients in various food matrices. We hypothesize that some bioactive compounds undergo chemical changes during food processing and storage. The objective was to investigate the stability of selected active compounds of St. John's wort, i.e., hyperforin (HF), hypericin (HP) and pseudohypericin (PSP), as affected by pH and light exposure in non-carbonated, fruit-flavored drinks. Known amounts of standard solutions or St. John's wort extracts were added to water, as a model system, and fruit-flavored drink samples at different pHs. The solutions were stored in dark or under laboratory light for various periods. The retention of active compounds was determined by reversed phase HPLC with UV detection. The data showed that at pH 2.8, these compounds were not stable in water especially under light exposure. The loss was less sever in drink samples, probably due to the presence of antioxidants in fruit drinks, but it was still significant. The retention values of active compounds were <50% after 48 hrs in dark and <10% under light. At higher pH, the stability of these compounds was improved in drink but varied somewhat in water. These results suggest that St. John's wort active components (HF, HP and PHP) are not stable at low pH aqueous solutions such as fruit-flavored drinks. The decrease is accelerated when the solution is stored in clear glass bottle under normal lighting conditions. These changes may result in the formation of degradation products, which could be of safety concern, as they are not intended to be found in fruit-flavored drinks.
Session 88, Nutraceuticals & Functional Foods: General
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