In vitro metabolism of rebaudioside B, D, and M under anaerobic conditions: Comparison with rebaudioside A

• Published in: Regulatory toxicology and pharmacology 2014-03, Vol.68 (2), p.259-268
• Main Authors: Purkayastha, Sidd, Pugh, George, Lynch, Barry, Roberts, Ashley, Kwok, David, Tarka, Stanley M.
• Format: Article
• Language: English
• Subjects: Anaerobic; Diterpenes, Kaurane - chemistry; Diterpenes, Kaurane - metabolism; Feces; Female; Glycosides - chemistry; Glycosides - metabolism; Human; Humans; Hydrolysis; In vitro metabolism; In Vitro Techniques; Male; Rebaudiosides; Steviol; Steviolbioside; Sweetening Agents - chemistry; Sweetening Agents - metabolism; Time Factors
• ISSN: 0273-2300; 1096-0295
• DOI: 10.1016/j.yrtph.2013.12.004

•Anaerobic metabolism of rebaudiosides A, B, D, and M was evaluated.•Pooled human fecal homogenates from males and females used as source of metabolism.•Metabolism to steviol of all rebaudiosides was complete after 24h incubation.•Safety data on other steviol glycosides are relevant to rebaudiosides B, D, and M. The hydrolysis of the steviol glycosides rebaudioside A, B, D, and M, as well as of steviolbioside (a metabolic intermediate) to steviol was evaluated in vitro using human fecal homogenates from healthy donors under anaerobic conditions. Incubation of each of the rebaudiosides resulted in rapid hydrolysis to steviol. Metabolism was complete within 24h, with the majority occurring within the first 8h. There were no clear differences in the rate or extent of metabolism of rebaudioside B, D, or M, relative to the comparative control rebaudioside A. The hydrolysis of samples containing 2.0mg/mL of each rebaudioside tended to take slightly longer than solutions containing 0.2mg/mL. There was no apparent gender differences in the amount of metabolism of any of the rebaudiosides, regardless of the concentrations tested. An intermediate in the hydrolysis of rebaudioside M to steviol, steviolbioside, was also found to be rapidly degraded to steviol. The results demonstrate that rebaudiosides B, D, and M are metabolized to steviol in the same manner as rebaudioside A. These data support the use of toxicology data available on steviol, and on steviol glycosides metabolized to steviol (i.e., rebaudioside A) to substantiate the safety of rebaudiosides B, D, and M.