Abstract

Background

Proanthocyanidins (PAC) are oligomers and polymers of flavan-3-ols with putative health benefits. PAC are prevalent in a wide variety of natural products and dietary supplements.

Objective

An inter-laboratory study was conducted to validate the 4-(dimethylamino)cinnamaldehyde (DMAC) colorimetric assay using a 96-well plate spectrophotometer for the accurate quantification of PAC in cranberry products and to evaluate the comparison of the procyanidin A2 (ProA2) dimer and cranberry PAC (c-PAC) reference standards.

Methods

Four test materials analyzed in this study included cranberry fiber powder, cranberry extract powder, concentrated cranberry juice, and a solution of cranberry PAC (30%, w/v). The samples were homogenized, extracted, sonicated, centrifuged, and analyzed using a 96-well plate spectrophotometer.

Results

Linearity for both the ProA2 and c-PAC standards was determined from 4.053 to 50.666 µg/mL and from 13.520 to 135.95 µg/mL, respectively. The relative standard deviation of repeatability (RSD_r) values for the four materials analyzed, using both ProA2 and c-PAC standards, met the Standard Method Performance Requirements (SMPR^®). Inter-laboratory precision using Horwitz ratio (HorRat) values for the four materials analyzed, using both ProA2 and c-PAC standards, satisfies the acceptance range in Appendix K of the Official Methods of Analysis (2003): Guidelines for Dietary Supplements and Botanicals. The limit of quantification (LOQ) was estimated to be 3.16 µg/mL.

Conclusions

The results produced from this study demonstrate the utility of the c-PAC standard over the ProA2 standard and the advantages of using a 96-well plate spectrophotometer for the accurate quantification of PAC.

Highlights

The use of a 96-well plate reader and c-PAC reference standard in the DMAC method improves accuracy and percision for quantification of soluble proanthocyanidins in cranberry foods and dietary supplements.

中文翻译：

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使用蔓越莓原花青素标准品对蔓越莓食品和膳食补充剂中可溶性原花青素进行定量的4-（二甲基氨基）肉桂醛（DMAC）实验室间验证，第一种行动正式方法SM：2019.06

抽象的

背景

原花青素（PAC）是flavan-3-ols的低聚物和聚合物，具有公认的健康益处。PAC广泛存在于各种天然产品和膳食补充剂中。

客观的

进行了实验室间研究以验证使用96孔板分光光度计对4-（二甲基氨基）肉桂醛（DMAC）比色测定法的准确性，以准确定量蔓越莓产品中的PAC，并评估原花青素A2（ProA2）二聚体的比较和蔓越莓PAC（c-PAC）参考标准。

方法

本研究中分析的四种测试材料包括酸果蔓纤维粉，酸果蔓提取物粉，浓缩酸果蔓汁和酸果蔓PAC溶液（30％，w​​ / v）。将样品均质化，提取，超声处理，离心，并使用96孔板分光光度计进行分析。

结果

ProA2和c-PAC标样的线性分别从4.053至50.666 µg / mL和从13.520至135.95 µg / mL确定。重复性（RSD的相对标准偏差_{- [R} ）值四种材料分析，同时使用ProA2和c-PAC标准，满足的标准方法的性能要求（SMPR ^®）。使用ProA2和c-PAC标准对四种被分析材料使用Horwitz比率（HorRat）值进行的实验室间精密度满足《官方分析方法（2003）：膳食补充剂和植物药指南》附录K中的接受范围。定量限（LOQ）估计为3.16 µg / mL。

结论

这项研究产生的结果证明了c-PAC标准相对于ProA2标准的实用性，以及使用96孔板分光光度计精确定量PAC的优势。

强调

在DMAC方法中使用96孔读板器和c-PAC参考标准品可提高蔓越莓食品和膳食补充剂中可溶性原花青素定量的准确性和准确性。