Anthocyanin Composition of Açaí Dietary Supplement and Conventional Food Products

Reviewed: Lee J. Anthocyanins of açaí products in the United States. NSF Journal. 2019;14-15:14-21.

Keywords: Açaí, anthocyanins, Euterpe oleracea, HPLC-UV/Vis

Continuing her research into the quality of anthocyanin-containing commercial products,^1-3 Jungmin Lee determined the composition and concentrations of anthocyanins in 37 dietary supplement and 19 conventional food products labeled to contain açaí (Euterpe oleracea, Arecaceae) fruit. Products were purchased online on amazon.com, or at local markets in Boise, ID.

Samples were analyzed using high-performance liquid chromatography (HPLC) with detection at 520 nm. Açaí is known to contain two major anthocyanins, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside. Cyanidin-3-O-sambubioside, peonidin-3-O-glucoside and peonidin-3-O-rutinoside have been reported as minor compounds.^4,5 The majority of commercial samples contained three (n = 25), or two (n = 17) anthocyanins. In these samples, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside were consistently present, while cyanidin-3-O-sambubioside was not detected in any of the samples. Of the 37 dietary supplements, seven samples (19%) did not contain any anthocyanins, and two showed an unusual anthocyanin fingerprint, suggesting that these products contained undeclared additional ingredients.

Comment: Using the anthocyanin fingerprint to authenticate botanical ingredients has been applied successfully in the past, e.g., in case of bilberry (Vaccinium myrtillus, Ericaceae) fruit or cranberry (V. macrocarpon) fruit. The task has proven more difficult with açaí, since the anthocyanin composition does not seem to be as consistent as for bilberry and cranberry.^6,7 For example, Mulabagal et al. published the results of an anthocyanin analysis of three açai powders and one capsule. While cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside were consistently present, the concentration ratios of cyanidin-3-O-glucoside to cyanidin-3-O-rutinoside varied from 1:0.17 to 1:2.75. Cyanidin-3-O-sambubioside was absent in one powder, but present at similar concentrations as cyanidin-3-O-glucoside in one powder and the capsule.⁸ An additional challenge is the known instability of anthocyanins, which oxidize readily, especially in liquid form. Due to the rapid degradation of anthocyanins in liquid formulations, it may not be surprising that the majority of the dietary supplements that lacked anthocyanins were liquid preparations. As such, the study underscores the need to include a diverse number of samples so the natural variation in the chemical composition of açaí can be determined to a meaningful degree.

References

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5. Schauss AG, Wu X, Prior RL, Ou B, Patel D, Huang D, Kababick JP. Phytochemical and nutrient composition of the freeze-dried Amazonian palm berry, Euterpe oleracea Maert. (açaí). J Agric Food Chem. 2006;54(22):8598-8603.
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7. Brown PN, Shipley PR. Determination of anthocyanins in cranberry fruit and cranberry fruit products by high-performance liquid chromatography with ultraviolet detection: single-laboratory validation. J AOAC Int. 2011;94(2):459-466.
8. Mulabagal V, Keller WJ, Calderón AI. Quantitative analysis of anthocyanins in Euterpe oleracea (açaí) dietary supplement raw materials and capsules by Q-TOF liquid chromatography/mass spectrometry. Pharm Biol. 2012;50(10):1289-1296.