The use of DNA-based methods to authenticate botanical dietary supplements has been vigorously debated for a variety of reasons. More comparisons of DNA-based and chemical methods are needed, and concordant evaluation of orthogonal approaches on the same products will provide data to better understand the strengths and weaknesses of both approaches. The overall application of DNA-based methods is already firmly integrated into a wide array of continually modernizing stand alone and complementary authentication protocols. Recently, the use of full-length chloroplast genome sequences provided enhanced discriminatory capacity for closely related species of Echinacea compared to traditional DNA barcoding approaches (matK and rbcL). Here, two next-generation sequencing approaches were used: (1) genome skimming and (2) PCR amplicon (metabarcoding). The two genetic approaches were then combined with HPLC-UV to evaluate 20 commercially available dietary supplements of Echinacea representing "finished" products. The trade-offs involved in different DNA approaches were discussed, with a focus on how DNA methods support existing, accepted chemical methods. In most of the products (19/20), HPLC-UV suggested the presence of Echinacea spp. While metabarcoding was not useful with this genus and instead only resolved 7 products to the family level, genome skimming was able to resolve to species (9) or genus (1) with the 10/20 products where it was successful. Additional ingredients that HPLC-UV was unable to identify were also found in four products along with the relative sequence proportion of the constituents. Additionally, genome skimming was able to identify one product that was a different Echinacea species entirely.

中文翻译：

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植物膳食补充剂的 HPLC-UV、Metabarcoding 和基因组脱脂：紫锥菊案例研究

出于各种原因，使用基于 DNA 的方法来验证植物性膳食补充剂已经引起了激烈的争论。需要对基于 DNA 的方法和化学方法进行更多比较，对相同产品的正交方法进行一致评估将提供数据，以更好地了解两种方法的优缺点。基于 DNA 的方法的整体应用已经牢固地集成到各种不断现代化的独立和补充身份验证协议中。最近，与传统的 DNA 条形码方法（matK 和 rbcL）相比，全长叶绿体基因组序列的使用增强了对紫锥菊密切相关物种的区分能力。在这里，使用了两种下一代测序方法：(1) 基因组撇取和 (2) PCR 扩增子（元条形码）。然后将这两种遗传方法与 HPLC-UV 相结合，以评估代表“成品”的 20 种市售紫锥菊膳食补充剂。讨论了不同 DNA 方法所涉及的权衡，重点是 DNA 方法如何支持现有的、公认的化学方法。在大多数产品 (19/20) 中，HPLC-UV 表明存在紫锥菊属。虽然元条形码对这个属没有用，而是只能将 7 个产品解析到家族级别，但基因组略读能够成功解析 10/20 产品的物种 (9) 或属 (1)。在四种产品中还发现了 HPLC-UV 无法识别的其他成分以及成分的相对序列比例。此外，